Access to guns and firearms is third in the top five health concerns of people in the US. What gets reported in the news media about gun violence gives the impression that most deaths from gun violence are murders and mass shootings. The actual data give a substantially different story. In this post I will write about the statistics on death from gun violence in the US as well as comparing it to that in some other countries.
Total deaths vs death rates
The number of gun violence deaths has been increasing in the US, but so has the population. The best way to know whether gun violence deaths are increasing, decreasing or staying the same is to look at death rates from gun violence per 100,000 people. The news media never report it that way.
Suicide
The most recent year for which we have complete data is 2021. In 2021, as in previous years a large majority of firearm deaths were suicides (54%). The rate of firearm suicides was 7.5 per 100,000 people. This essentially equals the peak gun suicide rate of 7.7 per 100,000 people which occurred in 1977.
Firearm suicides vary considerably by state. The states with the highest firearm suicide rates are Wyoming (22.8 per 100,000 people), Montana (21.1), Alaska (19.9), New Mexico (13.9) and Oklahoma (13.7).
The states with the lowest firearm suicide rates are Massachusetts (1.7 per 100,000 people), New Jersey (1.9), New York (2.0), Hawaii (2.8) and Connecticut (2.9).
For people with depression, access to a gun in the home increases the risk of suicide death by 300%. Suicide attempts by firearm result in death 90% of the time, while suicide attempts by other methods have a much higher survival. Of those who survive suicide attempts, 70% do not attempt suicide again. Men are much more likely to commit suicide by firearm than women, but a substantial number of women commit firearm suicides as well. Physicians, therapists and or family members should try to see that guns are removed from the home of any person who has major depression. Despite best efforts, that is not always possible.
Murder
In 2021 43% of the firearm deaths were murders. The firearm murder rate in the US was 6.7 per 100,000. It rose sharply to this value during the pandemic, but was still lower than the peak gun murder rate of 7.2 per 100,000 in 1974.
The firearm murder rate also varies markedly by state. The states with the highest firearm murder rates are District of Columbia (22.3 per 100,000 people), Mississippi (21.2), Louisiana (18.4), Alabama (13.9) and New Mexico (11.7).
The states with the lowest firearm murder rates are Massachusetts (1.5 per 100,000), Idaho (1.5), Hawaii (1.6), Utah (2.1) and Iowa (2.2).
Medical Response to Gunshot Wounds
People with gunshot wounds who make it to a level 1 trauma center within an hour have a significantly higher survival rate. Level 1 trauma centers are rarely located in poor neighborhoods where most of the gun violence happens. Murder rates therefore are affected by how well the medical system can get gunshot wounds to level 1 trauma centers. To really understand the level of gun violence, we need to know the total number of gunshot wounds, not only those who die from them. Unfortunately, no agency keeps those statistics. They are included under aggravated assault, which the FBI defines as an unlawful attack by one person upon another for the purpose of inflicting severe or aggravated bodily injury. That could include fist fights, knocking someone down, threatening someone with a knife or inflicting a gunshot wound. If the medical system is doing a good job, then the murder rate will be lower, despite the fact the gunshot wounds may be increasing. We currently have no way to measure this.
Change in gun violence deaths over time
Below is a graph showing firearm suicide and murder rates in the US since 1968.
Mass Murder
The CDC defines mass murder by firearm as 4 or more people killed or injured in an attack. Although mass murders are widely reported in the media, they account for only a tiny sliver of total deaths from firearms. Using this definition 706 people were killed in mass shooting incidents in 2021 compared to total firearm deaths in 2021 of 48,830. In other words mass shootings account for about 1% of total firearm deaths. That does not make them any less horrific, but the chance of any individual being killed in a mass shooting is not zero but is very tiny. The number of mass shooting incidents has increased, however, from 3 in 2000 to 61 in 2021.
Who is at risk of dying by firearm murder?
Black people and particularly black men are at markedly increased risk of being murdered by firearms. People of Hispanic origin and native Americans are also at increased risk. This is almost certainly partly due to inadequate access of these communities to prompt treatment at a level 1 trauma center. Below is a graph from the CDC showing gun murder by racial group and gender.
Firearm deaths in children
In 2021, firearms continued to be the leading cause of death among US children. From 2018 to 2021, there was a 41.6% increase in the firearm death rate in children. Over 3,000 children and adolescents ages 0 to 19 die each year in the U.S. from a firearm injury. In children and adolescents ages 10-19, approximately 4 in 10 of those deaths are suicides.
Firearm deaths in the US compared to other countries
Compared to other high income countries, the US has the highest rate of homicides from firearms. Below is a chart showing firearm homicide deaths for high income countries with populations over 10 million.
The US is also an outlier compared to other high income countries in firearm deaths of children. Below is a chart showing this.
Gun violence in Latin America is very high, due in part to the prevalence of criminal gangs and a vibrant drug trafficking industry. Countries that have a higher firearm death rate than the US are in the table below.
Nearly three fourths (72%) of gun owners say their guns are for protection. A little less than a third (32%) say they own a gun for hunting. Other smaller percentages reasons are gun collecting, sport shooting, or for their job. Among gun owners with only one gun, handguns are by far the most common type of gun: 62% say this is the type of gun they own, while 22% own a rifle and 16% own a shotgun.
Bottom Line
Most deaths from firearms in the US are suicides, about 54%. About 43% of firearm deaths are murders, of which a disproportionate proportion are black men and to a lesser extent black women. Mass murders make up 1% of deaths from firearms. The rest are accidental, involve law enforcement or are of undetermined cause.
Prompt access (within the first hour) to level 1 trauma centers substantially reduces the death rate from gunshot wounds. Poor communities, especially black communities tend to live far from a level 1 trauma center.
Firearm suicide and firearm murder rates vary markedly by state. Firearms are the leading cause of death in children in the US. The US has vastly more firearm deaths of both adults and children than all other high income countries.
The total number of firearm deaths in the US in 2021 was 48,830. Anything else that killed nearly 49,000 people in the US in 1 year would be considered a national health emergency. We could markedly reduce this death toll if we had the political will to do so. Just banning assault weapons is not an adequate response. That would barely make a dent in the total death rate from firearms. It would not reduce gun suicides (the major cause of firearm deaths). Hospitals who treat gunshot wounds would not notice any measurable difference.
Some of the information in this post comes from Malcolm Gladwell’s podcast, Revisionist History. He did a six part series on gun violence in the US this past August. It is tremendously informative, though not comfortable to listen to. If you have any interest in this topic (as everyone in the US should) I highly recommend listening to it.
It is expected that in 2024, 144 million people in the US will be using artificial sweeteners daily. The rationale for using non caloric or low caloric artificial sweeteners is of course to be able “to have your cake and eat it too.” That is, the sweet tooth can be satisfied without the known ill effects of sugar consumption. You can reduce your calories and therefore lose weight while still getting all the sweetness you crave. Is this true? Are artificial sweeteners safe? Do they help people lose weight? Are there ill effects from consuming artificial sweeteners over a long time? The answers to some of these questions are far from clear, but there is evidence to answer some of them.
There are six different sweetener compounds approved as food additives by the FDA. The FDA also approves the use of three plant and fruit based sweeteners as safe. To complicate things further, there are six FDA approved sugar alcohols (which have slightly less calories than sugar, but are metabolized differently). Below is a table listing all these sweeteners and their brand names. Scroll to the right to see the nutritive sweeteners in the table. Here is a link to the article containing the table
Used as an ingredient in food and beverage products
Stevia®, Truvia™, Sun Crystals®, PureVia™, Sweetleaf Sweetener™
Used as ingredient in food products.
XyloSweet
Used as ingredient in food products.
Zerose
The only thing all these compounds have in common is that they stimulate the human sweet taste receptor. Some are absorbed in the small intestine and some are not absorbed. They have (or may have) different effects on metabolism. Some of them are 2000 times as sweet as sugar and some (the sugar alcohols) are as sweet or half as sweet as sugar.
In this post I’m going to write about the pro and con evidence for each of these different classes of sweeteners. I’m also going to write about the effects of using honey, maple syrup and agave as sweeteners.
Human Taste
Humans have only five kinds of taste buds, mostly on the tongue, but some on the roof of the mouth and the throat. They are sweet, sour, bitter, salt and umami (spicy). All tastes are combinations of activity of these five kinds of receptors. Artificial sweeteners stimulate primarily the sweet taste buds. A few of them in larger quantities stimulate the bitter taste buds as well.
Do artificial sweeteners increase the risk of cancer?
The answer to this question is almost certainly no. There were some early studies of aspartame in rats that showed an increased incidence of bladder cancer. This turned out to be related to physiology specific to rats and not humans. There is no evidence at present to suggest that any artificial sweeteners increase the risk of cancer in humans. Obesity does increase the risk of cancer and many overweight people use artificial sweeteners. There is no evidence that the sweeteners themselves increase the risk of cancer.
Do artificial sweeteners help with weight loss?
The answer to this question is no. Almost all human and animal studies to date show no effect on weight loss or weight gain for any of the artificial sweeteners.
Do artificial sweeteners increase the risk of cardiovascular disease?
The answer to this question is probably yes. A large study in France showed that consumption of artificial sweeteners was associated with cardiovascular disease. The main ones consumed were aspartame, acesulfime potassium and sucralose. Apartame was associated with increased risk of stroke. Consumption of acesulfame potassium and sucralose was associated with an increased risk of coronary disease. Here is a link to that study in the British Medical Journal.
Do artificial sweeteners increase the risk of type 2 diabetes?
The answer to this question is complicated. The large study in France did show some increase in type 2 diabetes in the group that took the largest amount of artificial sweeteners. Some studies suggest that this effect may be due to the artificial sweeteners’ effect on the microbiome. Only sucralose, saccharine, and the sugar alcohols seem to affect the composition of the gut microbiome. It appears that people with certain kinds of composition of their microbiome are at risk of developing diabetes.
Other side effects of artificial sweeteners
People with irritable bowel syndrome may have increased symptoms from artificial sweeteners. People with inflammatory bowel disease (such as ulcerative colitis or crohn’s disease may have exacerbation of their symptoms from artificial sweeteners.
What about using honey, maple syrup, or agave as sweeteners?
Honey and maple syrup have some antioxidants that may be good for you, but they also have as much sugar as regular table sugar. Agave has mostly fructose as opposed to glucose, so it tends to make your blood sugar higher for longer. It also is only metabolized in the liver, and too much fructose can lead to fatty liver. Any of these in small amounts not too frequently is fine. The same is true for sugar.
Bottom Line
There are no health benefits to using any of the artificial sweeteners, including the ones derived from plants and fruits, and including the sugar alcohols. Evidence is accumulating that many of them may cause harm by increasing the risk of cardiovascular disease and adversely affecting the microbiome. You are much better off to use small amounts of sugar, honey, or maple syrup no more than a few times a week. You should avoid foods advertised as sugar free if any of the artificial sweeteners are listed on the label. Refer to the table at the beginning of this post to see what they are called.
There is a new treatment for early Alzheimer’s disease that has been approved by the FDA. The trade name is Lequimbi and the generic name is Lecanemab. It is a monoclonal antibody (all of this class of medicines end in “mab) that targets the protein called amyloid-beta that accumulates in the brain of many patients with dementia due to Alzheimer’s disease. The press has been full of articles about this treatment, but it is important to understand the evidence for how well it works and in what kind of patients. I will go through that evidence in this post.
Who does Lecanemab work for?
The study that led to the FDA approval was done in people with early Alzheimer’s disease or what is called mild cognitive impairment. People with mild cognitive impairment often progress to dementia from Alzheimer’s disease. All of the people in the study had confirmed amyloid-beta deposition in the brain documented by PET scan or spinal fluid from a spinal tap. Not everyone one who has dementia has amyloid. There are many other kinds of dementia including vascular dementia, Lewy body dementia, frontotemporal dementia, mixed dementia (more than one type), dementia from Parkinson’s disease, dementia from Huntington’s disease, dementia related to alcoholism, and dementia from posterior cortical atrophy. Lecanemab only works for people who have documented excessive amyloid, not for any other type of dementia. In order to be able to take the drug, amyloid has to be documented either by a PET scan or a spinal tap. It has only been used in early Alzheimer’s disease. It does not work in people who already have more severe dementia from Alzheimer’ disease.
How well does Lecanemab work?
The study that established the effectiveness of Lecanemab was a placebo controlled double blind randomized trial. That is the gold standard for a clinical trial, so the results should be very reliable.
To measure the degree of cognitive impairment, the investigators used a test called the Clinical Dementia Rating–Sum of Boxes (CDR-SB).
The CDR-SB is measured by semistructured interviews of patients and informants, and cognitive functioning is rated in 6 domains of functioning: memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care. Each domain is rated on a 5-point scale of functioning as follows: 0, no impairment; 0.5, questionable impairment; 1, mild impairment; 2, moderate impairment; and 3, severe impairment (personal care is scored on a 4-point scale without a 0.5 rating available). The range of scores is from 0 (no cognitive impairment) to 18 (severe impairment).
Patients were randomized to be in the treatment group or the control group. There were about equal numbers in both groups. The average baseline CDR-SB score for both treatment and control groups was about 3.2. out of 18 possible, so both groups had very mild impairment at baseline.
Results of the clinical trial of Lecanemab
The trial took place over 18 months. Lecanemab has to be administered through intravenous infusion every two weeks. The control group also got intravenous infusions, but only got a placebo and not the Lecanemab. Both treatment and control groups got slightly worse over the 18 months with increasing CDR-SB scores.
At the end of the 18 months, the CDR-SB score in the control group was 4.86, an increase of 1.66. The CDR-SB score in the Lecanemab group was 4.41, an increase of 1.21. That means that people who got Lecanemab progressed in their cognitive impairment somewhat more slowly than the people who got placebo. Although the difference was modest, it was highly statistically significant. The absolute risk decrease was 9%. The formula to calculate the absolute risk reduction (ARD) is 1-(4.41/4.86)=.09. The number needed to treat to benefit one person (NNT) is 1/.09 = 11. That number means that one out of 11 people with mild cognitive impairment from amyloid deposition will benefit from taking Lecanemab.
Adverse effects
Unfortunately the major adverse effects of Lecanemab are brain swelling and bleeding in the brain. In the clinical trial 12.6% of the treatment group had brain swelling or bleeding compared to almost zero in the control group. The Lecanemab group also had 26% more infusion reactions than the control group. We can calculate the number needed to harm (NNH) for one person to get brain swelling or bleeding. That formula is 1/0.126=7.9. That means that one out of every 8 patients who get Lecanemab will have brain swelling or bleeding. When the number needed to harm is less than the number needed to treat, that is not a good thing! Fortunately most of the people who had these abnormalities on scans did not have any symptoms. Nonetheless, potentially serious adverse effects from Lecanemab are common enough to be concerning.
Because of the risk of bleeding in the brain, anyone who is on any blood thinner including aspirin is not eligible for Lecanemab, nor is anyone else who may be pre-disposed to bleeding.
Cost
A one year supply of Lecanemab costs $26,500. Your Medicare part D, which pays for medicines, or your Medicare Advantage plan may or may not cover the cost of this drug. That cost does not include the cost of the PET scan or the spinal tap that needs to be done before anyone is eligible to to take Lecanemab.
Bottom Line
Lecanemab is the first drug that shows clear benefit in slowing the progression of Alzheimers’s disease related to amyloid-beta deposition in the brain. At this point the effects of Lecanemab on the progression of early Alzheimer’s disease are modest at best, at the cost of significant side effects. This research is promising, but at this point I think that the modest benefits may be outweighed by the very significant and sometimes dangerous side effects.
Most people know these new effective weight loss drugs by their trade names: Ozempic, Wegovy and Mounjaro. Ozempic and Wegovy are different names for semaglutide. Mounjaro is the trade name for tirzepatide. All of these drugs are in the same class. They are called GL-P1 agonists. They mimic the action of a hormone called glucagon-like peptide. These drugs were developed to treat type 2 diabetes. They lower blood sugar by causing insulin release and also by delaying stomach emptying, which delivers less glucose to the bloodstream. The slowing of emptying from the stomach decreases appetite and causes an increased feeling of fullness. People on these drugs tend to reduce their calorie intake fairly markedly and that is how they work for weight loss.
Common Side Effects
The most common side effects of all these long acting medicines are nausea, vomiting, abdominal pain and diarrhea. These side effects usually disappear within a few weeks, and are less likely to happen if they are started at a low dose and increased gradually. Occasionally they are persistent. Some somewhat less common side effects include headache, fatigue, dizziness, constipation, heartburn, bloating, belching and flatulence (passing gas). People with diabetes can sometimes get low blood sugar. Again, most of these side effects usually go away within a week or two. Occasionally they can be persistent.
Rare Side Effects
These side effects are rare, but much more serious and can result in hospitalization. They include severe allergic reaction, acute pancreatitis, gall stones, acute kidney injury, suicidal thinking, and cancer of the thyroid.
Long Term Effects
The evidence so far is that stopping these medicines results in weight gain back to the original weight. That means that people are likely to have to stay on these medicines to maintain the weight loss. We know that the medicines are relatively safe when taken for two years, but we have no idea what long term side effects might be, or even if the medicines will continue to work past two years.
How well do they work?
The medicines are given by injection once a week and they work very well. These are the most effective medicines for weight loss that we have ever had, and there are some new ones in the pipeline that may even work better. As with any medicine, there are risks as I have documented above as well as benefits. You would not want to take one of these medicines unless the benefit exceeds the risk.
Who should take these medicines and who should not?
Obesity increases the risk of diabetes, heart disease and cancer, especially colorectal cancer. The best predictor of risk of disease from obesity is the waist circumference. Just take a tape measure and measure your waist at the level of the belly button. If you are female your risk of cancer starts to increase if your waist circumference is more than 31.5 inches. Your risk of cancer, especially colorectal cancer increases 5% for every inch above 31.5 inches. Above 35 inches the risk of diabetes, and cardiovascular disease starts to go up. For men the numbers are 37 inches for the risk of cancer going up and 40 inches for the risk of diabetes and cardiovascular disease.
The best treatment for obesity is prevention. That means eating unprocessed foods and regular exercise. If you are already overweight or especially if you are obese, it is very hard to lose weight and keep it off. Once you lose weight, your body thinks it is starving and all kinds of hormones and body changes kick in to try to get the weight back.
If your waist circumference is over 31.5 if your are female and 35 if you are male, then you are a candidate for one of these new weight loss medicines. For you the benefit likely outweighs the risk. If your waist circumference is less than those values, then the risk of taking these medicines is much higher than the potential benefit.
Cost
If your insurance does not cover medicines for weight loss the cost of these medicines may be prohibitive.
Wegovy costs $1,349.00 a month without insurance.
Ozempic costs $892.00 a month without insurance.
Muanjaro costs $1,300 a month without insurance.
Unfortunately many insurance plans do not cover weight loss medicines.
In this post I will write about how the evidence for how well medicines work, and the risk of side effects are not always what they seem. I’m going to show that relative risk reduction (or relative risk increase) always looks a lot bigger than absolute risk reduction or absolute risk increase. Journals and advertisements always report relative risk reduction for medicines or other treatments because they look more impressive. On the other hand, side effects are almost always reported as absolute risk increase because that looks a lot smaller. I will show you how to calculate both kinds of risk reduction and increase. I will argue that absolute risk reduction or increase is what you really want to know before deciding to take a medicine or other treatment.
Any study of a medicine or treatment always has a group that gets the treatment and a group that gets a placebo. That is the only way to know if the medicine or treatment really works. There is always a placebo effect for any medicine. That is, a certain portion of the people who get a placebo get better. If the number of people who get better from the actual treatment is higher than the number of people who get better from the placebo, then the treatment works.
People who participate in a study know that they might get the treatment or a placebo, but they don’t know which one they got until the end of the study. In medical terminology, they are blinded from knowing whether they got treatment or placebo. If the study is double blind (the most reliable kind) then neither the investigators who administer the treatment nor the participants know which study participants got the study treatment or the placebo until the end of the study.
If the treatment works better than the placebo, that result can be reported in several different ways
Relative Risk Reduction or Increase
Relative risk is the proportion of people who have the disease or condition being studied in the treatment group divided by the proportion of people who have the condition in the placebo group.
For example, let’s say we are testing a treatment to prevent diabetes. The control group and the treatment group each have 100 people. 30 people get diabetes in the control group and only 10 people get diabetes in the treatment group. The risk in the treatment group is 10/100 = 0.1 The risk in the placebo group is 30/100 = 0.3 To compare those risks we divide the risk in the treatment group by the risk in the control group. 0.1/0.3= .33. That means that the relative risk of diabetes in the treatment group is 1/3 of the risk in the placebo group. To change that to the relative risk reduction percentage we use the formula 100(1- Relative Risk). Plugging our values into that formula gives 100(1-.33)= 67%. In other words, the treatment reduces the risk of diabetes by 67% relative to the risk of diabetes in the placebo group. That sounds like a big treatment effect!
All medicines or treatments have some side effects. Placebos can have side effects too, especially if people are told (as they must be) what are the possible side effects of the treatment. Placebo side effects are called “nocebo” effects.
In the hypothetical diabetes study described above, let’s say that a side effect of the treatment is bladder infection. Let’s suppose that 5 out of the 100 people in the treatment group get a bladder infection while only 1 out of 100 in the control group get a bladder infection. The relative risk of a bladder infection in the placebo group is 1/100=0.01. The risk of bladder infection in the treatment group is 5/100=.05. The relative risk of getting a bladder infection in the placebo group compared to the treatment group is .01/.05=0.2. To change that to a relative percentage increase, we use our formula again. 100(1-.2)=80%, This means that the risk of the side effect of bladder infection is 80% more likely in the treatment group compared to the risk of bladder infection in the placebo group.
Absolute Risk Reduction or Increase
Relative risk reduction or increase does not take into account the baseline risk of getting the disease or condition. Absolute risk reduction does take into account the baseline risk.
In our example above the absolute risk reduction is 30% (risk of diabetes in the control group) minus 10% (risk of getting diabetes in the treatment group) = 20%. That means that treatment reduces risk of diabetes by 20%. Notice that this is a much smaller number than the 67% relative risk reduction, but it more accurately reflects how much the treatment would reduce your risk of diabetes.
In our example the absolute risk increase of getting a bladder infection with treatment is 5% (the risk of bladder infection in the treatment group) minus 1% (the risk of getting bladder infection in the control group) = 4%. That means that the risk of getting a bladder infection from the treatment is 4% more than no treatment. Again, a much smaller number than relative risk increase of 80%.
Number Needed to Treat (or Harm)
Another way to look at how well a medicine or treatment works compared to placebo is the number of people that need to be treated in order to help one person. This is called Number Needed to Treat, abbreviated as NNT. The NNT = 1 divided by the absolute risk reduction. In our example the absolute risk reduction of getting diabetes in the treatment group was 20%. 1 divided by 0.20 = 5. That means you would need to treat 5 people to prevent 1 case of diabetes with this hypothetical treatment.
Number Needed to Harm, abbreviated as NNH is 1 divided by absolute risk increase. In our hypothetical example NNH = 1 divided by .04 = 25. This means that you would need to treat 25 people for one person to get a bladder infection
A Real World Example: Fosamax to prevent hip fracture in women with osteoporosis
In the real world, we rarely see a treatment effect as big as in our hypothetical example. Let’s look at a real study on a real medicine. Here are some numbers from a big four year study on using Fosamax (generic name alendronate) to prevent hip fracture in women with osteoporosis (thinning of bones). This study was reported in the Journal of the American Medical Association (JAMA) in 1988. It was the first large study to show that alendronate reduced hip fractures in women with osteoporosis. The study included over 4000 women with osteoporosis (shown by a type of bone scan called a DEXA scan). There were 2,218 women in the placebo group and 2,214 women in the treatment group. In the placebo group 812 women (36.6%) had severe bone thinning in the hips by Dexa scan. In the treatment group 819 (37%) women had severe bone thinning in the hips by Dexa scan. Over the four years there were 18 hip fractures in the placebo group (2.2%) and there were 8 hip fractures in the treatment group (1%)
Now lets do our calculations:
Relative Risk = .01 divided by .022 = .45. Relative Risk Reduction = 100(1-.45)= 55%. . This large relative risk reduction is what the article describing the study reported.
Absolute Risk Reduction = 2.2% – 1% = 1.2%. As you can see, the absolute risk reduction is tiny. Taking alendronate for 4 years reduced hip fracture by only about 1%.
Number Needed to Treat = 1/1.2% = 83.3. That means you would need to treat 83 women for four years to prevent one hip fracture.
Side Effects
Muscle or bone pain
In other studies, muscle or bone pain, sometimes severe was reported by 4% in the treatment group and 2.5% in the placebo group.
Relative Risk = .025 divided by .04 = .625. Relative Risk Increase = 100(1-.625)=37.5%. That means that bone and muscle pain are 37.5% more likely in the treatment group relative to the risk in the placebo group.
Absolute Risk Increase = 4% – 2.5% = 1.5%. This means that there is only a 1.5% increase in risk of muscle or bone pain when taking alendronate.
Number Needed to Harm = 1 divided by 1.5% = 67. That means you would need to treat 67 people for one person to have muscle or joint pain. Notice that the number needed to harm is less than the number needed to treat to prevent 1 hip fracture!
Osteonecrosis of the jaw
This is a rare but very serious side effect of alendronate. Assuming treatment group effect of .01% versus placebo of essentially zero let’s do our calculations.
Relative Risk Increase: since this complication is so rare, there are no trials comparing it with placebo.
Absolute Risk Increase: .01 %.
Number Needed to Harm: 1 divided by .01 % = 1000. This means that 1000 people would be treated before you would see one person with this serious complication.
Bottom Line
Journal articles and advertisements almost always report relative risk reduction for medicines or treatments because it makes the effect of the medicine or treatment look bigger. Side effects are almost always reported as absolute risk increases because it makes them look smaller.
Absolute Risk Reduction or Increase is what you really want to know when you are considering taking a medicine or treatment. Most of the time you will not be able to calculate absolute risk reduction, because you won’t have the actual percentages from the placebo and the treatment groups. Don’t despair though. Dr. Google is there to help. Using the following Google search will usually give you the absolute risk reduction. Type in “absolute risk reduction for (name of medicine or treatment).
Once you have the Absolute Risk Reduction (ARR) or Absolute Risk Increase (ARI)you can calculate for yourself the Number Needed to Treat or the Number Needed to Harm. Just divide 1 by either ARR or ARI.
Medical care in the US is the most expensive in the world, but almost all our health outcomes are worse than other industrialized countries. We talk a lot about US populations that don’t have enough access to medical care, but this post is about people who get more medical care and procedures than they need. It turns out that too much medical care not only adds to costs, but is actually as bad for you as not getting enough medical care. I’m going to write about both diagnostic and surgical procedures that are unnecessary at best, and dangerous at worst.
Unnecessary Diagnostic Tests
Routine lab work at your annual preventive care visit
It is common for doctors to order “routine” lab work at preventive care visits. This often includes a complete blood count (CBC), a comprehensive metabolic panel (CMP), a lipid panel and a hemoglobin A1C (a long term blood sugar test).
Healthy people who are not overweight and have no symptoms don’t need any of these, except perhaps the lipid panel to screen for high cholesterol but not even that every year. If you are overweight and sedentary, then it makes sense to screen for diabetes or pre-diabetes with an annual hemoglobin A1C. If you have high blood pressure then it makes sense to do a basic metabolic panel, which includes a measure of kidney function once a year. Other lab work should be based on symptoms and risk factors.
One reason that doing unnecessary lab work is dangerous as well as costly is that the more tests you do on someone, the greater the statistical chance that at least one of them will be abnormal. That can lead to a cascade of further tests and even dangerous procedures.
Imaging for low back pain
There is no reason to do x-rays. CT scans or MRI scans for acute low back pain unless it lasts for more than 6 weeks. Imaging should be done sooner if “red flag” symptoms are present such as:
Fever or chills
Recent illness or surgery
Recent severe back injury
History of cancer
Unexplained weight loss
Night pain or pain at rest
Urinary or fecal Incontinence
Saddle anesthesia (loss of feeling in the buttocks and inner thighs)
Weak, numb, or painful leg muscles
Abnormalities on imaging, especially CT and MRI are often present in people who have no back pain. Imaging without red flags, could lead to unnecessary surgery or back injections.
CT or MRI scan for headache with no findings on neurologic physical exam
Headaches are common and the vast majority do not have a serious cause. Headaches without any other symptoms or history of head injury do not need any imaging. Headache in people who have a history of migraine headaches also do not need imaging. There are certain “red flag” symptoms that do require an immediate CT or MRI scan. These include:
Signs of systemic illness (e.g., fever, stiff neck, rash).
Worst headache ever.
Progression in frequency and severity of headaches.
New headache in patients older than 50 years.
Sudden onset of headache – “thunderclap headache.”
New-onset headache in an immunocompromised or cancer patient.
Headache after head trauma.
Headache worsening with Valsalva (straining like you do to have a bowel movement).
DEXA scan for osteoporosis in low risk women before age 65 and in low risk men before age 70
The risk of fractures due to osteoporosis is extremely low in women under 65 and men under 70 who have none of the high risk factors outlined below. DEXA scans in people in this low risk population are not only unnecessary but also result in unnecessary radiation exposure. Radiation exposure is cumulative and can increase the risk of cancer.
Risk factors for osteoporosis include: a family history of osteoporosis, previous fractures, dementia, poor nutrition, cigarette smoking, alcoholism, low weight and body mass index, estrogen deficiency, early menopause (i.e., before age 45) or prolonged lack of menstrual periods in premenopausal women, long-term low calorie intake, history of falls, and inadequate physical activity.
Ultrasound of carotid arteries (carotid dopplers) in people who have no symptoms
People who have no symptoms are unlikely to benefit from carotid stents or surgery even if they have partial obstruction of the carotid arteries. They are much more likely to be harmed by surgery including risk of stroke, heart attack, or even death.
Carotid dopplers are only indicated for people who have symptoms suggestive of a stroke or mini stroke (TIA)
Routine PSA screening for prostate cancer in men
Although a few men’s lives will be saved by routine PSA testing, many, many more will have surgery for slow growing prostate cancer that would never affect their health, resulting in urinary incontinence and sexual dysfunction for a good portion of those.
PSA screening for prostate cancer should always involve shared decision making with the patient. Some people who have a strong family history of prostate cancer or other risk factors may opt for screening. It should never be routine.
Prostate cancer screening should not be done at all in men over 70. The chance of finding anything other than low grade prostate cancer that does not need treatment in men over 70 is very low.
Annual EKG’s (or any other heart screening test) in low risk people without symptoms
Heart screening tests, including resting EKG and exercise stress testing in people in a low risk population have a much higher false positive rate than true positives. This can result in unnecessary invasive procedures including cardiac catheterization and unnecessary heart surgery.
People with multiple risk factors might benefit from screening tests. Here is a link to a heart disease risk calculator: CV Risk Calculator. You will need to know your LDL and HDL levels to use this calculator. If your 10 year risk is over 10%, you might benefit from one of the heart disease screening tests.
Pap smears under age 21 and over age 65
A pap smear is a screening test for cervical cancer, which is caused by chronic infection with the HPV (wart) virus. Women under 21 who are infected with HPV most often clear it without treatment. It therefore makes no sense to screen women under 21 for cervical cancer. Women over 65 whose last pap smear or HPV test was normal have almost zero risk of contracting HPV, so no longer need pap smears.
Annual pap smears are no longer needed for anyone. Pap smears are recommended every 3 years for women age 21-29 and every 5 years from age 30-65 as long as an HPV test is done also.
Unnecessary Procedures
Stents for stable angina
Stents in the coronary arteries can be life saving for heart attack or unstable angina (heart pain that is getting progressively worse). Many people, however have stable coronary disease. They get pain with a predictable amount of exercise that goes away when they rest. It stays the same and does not get worse with time. People with this kind of stable heart disease do just fine when treated with medicines and lifestyle changes. They do not need stents. In fact, stents do not decrease all cause mortality (death) 4 years later compared to treatment with medicines. Some studies suggest that up to half of coronary stent insertions are unnecessary. Stent insertion is an invasive procedure that can have complications including death. You definitely don’t want to have one if it isn’t likely to extend your life significantly.
Hysterectomy (removal of the uterus) for benign disease
Most “elective” hysterectomies are done because of fibroid (benign) tumors, excessive vaginal bleeding, or endometriosis. All of these conditions have alternative less invasive effective treatments. Fibroids that are causing symptoms can be removed without a hysterectomy. Persistent vaginal bleeding can be treated with hormones or with removal of the lining of the uterus without doing a hysterectomy. Endometriosis can usually be treated effectively with hormones. Hysterectomy should be done only for cancer or when alternative treatments for benign disease have been tried and have not been effective.
Knee arthroscopy for arthritis
Osteoarthritis of the knee is one of the most common chronic healthcare conditions. It involves gradual deterioration of the joint surfaces including tears of the menisci. Knee arthroscopy involves using a tiny camera to look inside the knee through a small incision. Another small incision is made to insert small surgical tools. When orthopedists recommend this procedure to patients, they often say that they are going to “clean out” the knee. This means removing fragments of torn cartilage and pieces of meniscus.
People get temporary relief if any from this procedure. It is considered unnecessary surgery. It exposes one to the risks of general anesthesia and possible infection from the procedure.
Vertebroplasty for osteoporotic compression fractures
Compression fractures of the spinal vertebrae are relatively common in women (or men) with osteoporosis. Many times these are not painful and are found incidentally on x-rays. Sometimes they are painful, especially when they first happen. Vertebroplasty involves injecting cement into the fracture site to stabilize it and reduce pain. Most of the time short term pain medicines and temporary spinal braces provide adequate pain relief. There have been no well conducted double blind studies of vertebroplasty, so it is not known how much of the pain relief from this procedure is simply a placebo effect. It may help in very selected patients, but should only be done for persistent pain when conservative measures have failed.
Spinal fusion for back pain
Chronic back pain is a common condition. It can result from arthritis of the spine or can still be present even with normal x-rays. Spinal fusion surgery connects two or more spinal vertebrae together with small screws. Bone chips from the hip bone are used at the site of surgery as a bone graft, which eventually fuses the vertebrae together.
Spinal surgery of any kind, but especially spinal fusion is never appropriate for people with chronic back pain who have normal back x-rays. Osteoarthritis of the lower back, which does show up on x-rays, is best treated conservatively with physical therapy, non-narcotic pain medicines and walking as much as tolerated.
Spinal fusion is only indicated when there is severe instability of the spine that is causing pressure on the spinal cord. This is not a common finding, so spinal fusion is only rarely indicated.
One problem with spinal fusion is that there is increased mobility of the spinal facet joints above the level of the fusion, which can cause recurrent pain. This can lead to another fusion, which is caused by the first one.
Bottom Line
Unnecessary diagnostic tests and lab work increase the probability of unnecessary surgical procedures. You should ask your doctor or nurse practitioner the reason for any diagnostic tests or lab work that they order. If the answer is “routine” then you should consider declining the test.
If any elective surgery (that means not emergency surgery) is recommended you should ask if there is a more conservative option. You may also always request a second opinion. For any of the low value procedures outlined above you should be very wary of having that procedure unless you have one of the red flag indicators.
Medicare Advantage Plans are private insurance plans for people eligible for traditional Medicare. Medicare pays the plans an amount per person enrolled in their plan. The payment is based on the cost of care per person for traditional Medicare by region.
These plans are aggressively marketed promising extra services that Medicare does not cover, such as vision, dental care and hearing aid services. Most plans also include prescription drug coverage. You still have to pay your Medicare part B premium in addition to the premium for the Medicare Advantage plan, but that premium is usually quite low, or even zero depending which zip code you live in. Some plans even include things like gym memberships.
So what’s the problem? Sounds like you get more services for less cost. Actually there are a lot of problems. I will outline them below.
Traditional Medicare
Before going into the gory details of Medicare Advantage plans, I want to make sure readers understand how traditional Medicare works.
Medicare Part A
Medicare part A is hospital insurance. It also covers rehab in a skilled nursing facility, home health care and hospice care. It is available to people at age 65 and is free. Once you turn 65 you should sign up for Medicare part A even if you are still employed. It pays 100% of costs for the first 60 days of hospitalization after you pay a $1,600 deductible. After 60 days the copay is $400 per day.
Medicare Part B
Medicare part B is like traditional health insurance. It covers 80 % of things like medical services, procedures, ambulance services, labs and imaging. It does not cover most prescription drugs. Part B requires a premium (based on your previous year’s tax return) and is automatically deducted from your social security income. You can sign up for Medicare part B at age 65, or when you retire and no longer have employer based health insurance. If you sign up More than 7 months after you become eligible, your Medicare part B premium will include a penalty payment for as long as you have Medicare. Since the uncovered 20% can be substantial, most Medicare recipients purchase a private insurance policy to cover the other 20%. These are called Medigap policies and are offered by many insurance companies. If you sign up for a Medigap policy the same time as you sign up for Medicare, the premium cannot be based on your risk or pre-existing conditions. Generally these policy premiums are around $50-60 per month.
Medicare Part D
Medicare part D covers prescription drugs. It is administered by private insurers. There are.a dizzying number of part D plans (801 in 2023), and the prescription drugs covered can vary markedly. Premiums for Medicare Part D can range from less than $10 a month to more than $50 a month. Fortunately Medicare has a website that allows you to enter the drugs you take and get a list of plans that cover those medicines as well as the premiums they charge.
Problems with Medicare Advantage Plans
Medicare Advantage plans work well for people that are healthy, and don’t need much medical care. If you are sick, or if you become sick and you have one of these plans, the co-pays and deductibles are often quite high.
Hospitalization Costs are Higher
A recent Kaiser Family Foundation study found that over half of Medicare Advantage beneficiaries would pay more out of pocket costs for a five day hospitalization than people with traditional Medicare! Here is a link to that study Beneficiary Experience, Affordability, Utilization, and Quality in Medicare Advantage and Traditional Medicare: A Review of the Literature. The study also found that despite the claim by insurance companies that Medicare Advantage plans are better, the study found no overall “Advantage” to Medicare Advantage plans over traditional Medicare.
Your physician may not be in the network
Medicare Advantage plans have a limited network of primary care and specialty care physicians that are covered by the plan. You can see out of network physicians, but there is a substantial financial penalty for doing so. Also if you travel out the coverage area and get sick and have to see a physician or go to the ED, you will be hit with out of network costs. That is not the case with traditional Medicare, because almost all physicians accept Medicare.
The Network may not include the best hospitals or nursing facilities
Medicare Advantage plans often do not include the best hospitals or nursing facilities in their networks. This is especially true for cancer care. Traditional Medicare beneficiaries on average are admitted to better hospitals for cancer care and to more highly rated nursing facilities.
Prior Authorization
Almost all Medicare Advantage plans require prior authorization for many tests, imaging and procedures, as well as for hospitalizations. That means someone from the physician’s office has to call or fax the Medicare Advantage plan to get permission. Sometimes the physician himself/herself has to call and talk to a physician that works for the plan. If authorization is denied, then the beneficiary is responsible for all of the cost. Traditional Medicare, on the other hand almost never requires prior authorization for anything.
Multiple Co-pays
With Medicare Advantage plans there are multiple co-pays for the same issue. You pay a co-pay for your doctor’s visit; another co-pay if he refers you to a specialist; another co-pay for lab tests; another co-pay if your physician orders imaging. With traditional Medicare with a Medigap plan, once you pay the Medigap modest premium, you pay virtually nothing for doctor’s visits, specialist visits, lab tests or imaging.
High Out-of-Pocket Limits
According to the Kaiser Family Foundation study, In 2022, the weighted average out-of-pocket limit for Medicare Advantage enrollees was $4,972 for in-network services and $9,245 for in-network and out-of-network services combined.
Plan Benefits, Costs and Providers Change Every Year
Medicare Advantage plans are allowed by CMS to make these kinds of changes every year, and most of them take advantage of that. That means you need to read the fine print in your Medicare Advantage plan every year. Most people do not do this.
Switching Back to Traditional Medicare
If you discover that your costs are too high in a Medicare Advantage Plan, you can switch back to traditional Medicare. If you do that within 12 months of joining the Medicare Advantage plan, then you can get Medigap coverage with no underwriting (assessing your medical risk). If you switch after 12 months, the Medigap plans can exclude coverage for pr-existing, conditions, increase your premiums, or deny you coverage altogether. The bottom line is that your high costs could be permanent, even if you switch back to traditional Medicare.
Number of Plans
In 2022 there were nearly 4000 Medicare Advantage Plans offered by thousands of insurance companies. Humana and United Health Care Medicare Advantage plans account for nearly half of the enrollees. There is no website, like there is for Part D Medicare that lets you compare plans. All of these plans have different benefit structures and provider networks. This makes choosing a plan very difficult. Here is a graph from the Kaiser Family Foundation showing the proportion of Medicare Advantage enrollees by insurance company.
Bottom Line
Medicare Advantage Plans are only a good deal if you are healthy. Since illness and suffering await all of us sooner or later, signing up for a Medicare Advantage plan is a little like playing Russian Roulette. Overall, Medicare Advantage plans offer no “Advantage and considerable risk of increased costs. If you are eligible for Medicare, I would suggest sticking with traditional Medicare. It is generally a much better deal.
Although we talk about cancer as if it were one disease, it is actually many different diseases. Some are common, and some are rare. In this post I’m going to write about the five most common cancers in the United States. I will focus on incidence (how common they are in the population), risk factors for these cancers, and especially risk factors that can be reduced or eliminated. I will not talk about screening for cancer. That will be the subject for another post
Breast Cancer
Breast cancer is the most common cancer in the U.S. The incidence of breast cancer in the U.S. is 128 new cases per 100,00 women per year (men get breast cancer too, but at a much lower rate). That means that one tenth of one percent of women in the U.S get breast cancer every year. The population risk increases with age. The lifetime risk of developing breast cancer is 13 per cent, or about one in eight women. The majority of that risk is in women over the age of 65. Overall, 20% of women with breast cancer eventually die from it. That means the cure rate is 80%.
Things you can do to reduce your risk of getting breast cancer
Eat a high fiber diet with lots of vegetables and avoid lots of red meat, animal fat and processed foods. Studies have shown that this kind diet reduces the risk of getting breast cancer. Of course this kind of diet also reduces the risk of heart disease and stroke as well, as I have written about in previous posts.
Be physically active. Women who are not physically active have a higher risk of getting breast cancer. There are lots of ways to be physically active. Take at least one flight of stairs instead of taking the elevator. Park as far as you can from the store when you are shopping. Take some long walks in your neighborhood if that is safe where you live. If not, drive or take the bus to a nearby park to walk.
Maintain a healthy body weight. Older women who are overweight or have obesity have a higher risk of getting breast cancer than those at a healthy weight.
Don’t take hormones (if you can help it). If you do need hormones for menopausal symptoms, take estrogen only, not estrogen and progesterone and take it for less than 5 years if possible. Some forms of hormone replacement therapy (those that include both estrogen and progesterone) taken during menopause can raise risk for breast cancer when taken for more than five years. Certain oral contraceptives (birth control pills) also have been found to raise breast cancer risk.
Reproductive decisions. Have your first pregnancy before age 30 if possible, and breast feed for as long as is practical whatever age you have children. Having a first pregnancy after age 30, not breastfeeding, and never having a full-term pregnancy can raise breast cancer risk.
Don’t drink alcohol or have no more than one drink per day. Studies show that a woman’s risk for breast cancer increases with the more alcohol she drinks.
Don’t smoke, or quit if you do: Studies show that smoking cigarettes increases women’s risk for breast cancer
Risk Factors for Breast Cancer You Can’t Change
Getting older. The risk for breast cancer increases with age. Most breast cancers are diagnosed after age 50.
Genetic mutations. Women who have inherited changes (mutations) to certain genes, such as BRCA1 and BRCA2, are at higher risk of breast and ovarian cancer.
Reproductive history. Starting menstrual periods before age 12 and starting menopause after age 55 expose women to hormones longer, raising their risk of getting breast cancer.
Having dense breasts.Dense breasts have more connective tissue than fatty tissue, which can sometimes make it hard to see tumors on a mammogram. Women with dense breasts are more likely to get breast cancer.
Personal history of breast cancer or certain non-cancerous breast diseases. Women who have had breast cancer are more likely to get breast cancer a second time. Some non-cancerous breast diseases such as atypical hyperplasia or lobular carcinoma in situ are associated with a higher risk of getting breast cancer.
Family history of breast or ovarian cancer. A woman’s risk for breast cancer is higher if she has a mother, sister, or daughter (first-degree relative) or multiple family members on either her mother’s or father’s side of the family who have had breast or ovarian cancer. Having a first-degree male relative with breast cancer also raises a woman’s risk.
Previous treatment using radiation therapy. Women who had radiation therapy to the chest or breasts (for instance, treatment of Hodgkin’s lymphoma) before age 30 have a higher risk of getting breast cancer later in life.
Exposure to the drug diethylstilbestrol (DES). DES was given to some pregnant women in the United States between 1940 and 1971 to prevent miscarriage. Women who took DES, or whose mothers took DES while pregnant with them, have a higher risk of getting breast cancer.
Hormonal changes from night shift work: Some studies have shown that night shift work may increase the risk of breast cancer.
There is no point in worrying about things you can’t change, but if you are at increased risk for breast cancer from one or more of these risk factors, that might affect your decisions about whether and when to get screening mammograms. More about screening in another post.
Prostate Cancer
Prostate cancer is the second most common cancer in the U.S. It is the most common cancer in men. The incidence of prostate cancer in the U.S. is 113 per 100,00 men per year. That means, like breast cancer for women, about one tenth of one per cent of men will be diagnosed with prostate cancer every year. Like breast cancer, the population risk increases with age. The lifetime risk of developing prostate cancer for a male is 13 per cent or about 1 in 8. That is about the same lifetime risk risk for women for breast cancer. Overall 3.2% of men will eventually die from prostate cancer. That is a cure rate of 96.2%, much higher than for breast cancer. Part of the reason for the low death rate is that many prostate cancers grow so slowly that more men die with prostate cancer than from prostate cancer.
Risk Factors for Prostate Cancer
Things you can do to reduce your population risk of getting prostate cancer
Diet: Once again, a diet low in animal fat, high in unprocessed and high fiber foods, especially cruciferous vegetables like broccoli and cauliflower seem to be especially protective. Tomato based products, which are high in lycopene also seem to reduce population risk of prostate cancer. Soy intake as well as drinking coffee also seems to be protective.
Alcohol. Alcohol intake does not seem to be a a risk factor for prostate cancer. It is a risk factor for some other cancers that I will write about later.
Don’t smoke cigarettes (or marijuana). Smoking both cigarettes and marijuana increase the risk of prostate cancer
Maintain a normal body weight. Like for breast cancer, obesity increases the risk for prostate cancer.
Exercise. While exercise is good for you in lots of ways, it does not seem to decrease the population risk for prostate cancer.
Risk Factors for prostate cancer you can’t change
Age. Prostate cancer rarely occurs before the age of 40, but peaks between age 65 and 74. Autopsy studies have shown that low grade prostate cancer, never diagnosed during life, is extremely common as age increases. In men 71-80 it can be up to 73%! These low grade prostate cancers never caused any symptoms and the men in the autopsy studies died from something else.
Heredity. If family members have had prostate cancer, especially first degree relatives (father, grandfather) your population risk for prostate cancer is substantially increased
Race. Black men are more likely to get prostate cancer and also more aggressive prostate cancer.
Chemical exposure. Exposure to certain chemicals, especially the herbicide agent orange increase the population risk of prostate cancer.
Once again, there is no point in worrying about things you can’t change. Screening for prostate cancer is very controversial. More about that in another post.
Lung Cancer
Lung cancer is the third most common cancer in the U.S. The incidence of lung cancer is 52 per 100,000 per year, which translates to five one hundredths of 1 per cent of the U.S. population per year that will be diagnosed with lung cancer. The lifetime risk of lung cancer is about 6% of people in the U.S. Of those diagnosed with lung cancer, only 23% will live 5 years after diagnosis. That is a much lower cure rate than for breast cancer and prostate cancer.
Smoking. Smoking cigarettes or cigars or smoking a pipe are the biggest risk factor for lung cancer. People who quit smoking before age 40 have a 90% reduction in smoking related diseases including lung cancer. People who quit smoking by age 54 reduce their risk by two thirds. The risk of lung cancer is still somewhat increased for former smokers as compared to never smokers even 30 years after quitting smoking.
Second Hand Smoke. Breathing other smoker’s smoke also increases your risk of getting lung cancer by 20-30%.
Radon. Radon is the second leading cause of lung cancer after smoking. Radon is a naturally occurring gas that forms in rocks, soil, and water. It cannot be seen, tasted, or smelled. It can accumulate in buildings, especially basements. Homes can be tested for Radon and a simple ventilation fan can decrease radon to safe levels. If your house has not been tested for Radon, it should be. You can buy Radon test kits at a hardware store or on Amazon.
Asbestos Exposure. People who have been exposed to asbestos have an increased risk of lung cancer. Asbestos used to be used as insulation in buildings, but has been banned for years. Asbestos is still in some homes. It is of no risk to residents of those homes as long as it is not disturbed. The risk comes when houses that contain asbestos are torn down or re-modeled.
Other Workplace Exposures.
Other carcinogens (cancer-causing agents) found in some workplaces that can increase lung cancer risk include:
Radioactive ores such as uranium
Inhaled chemicals such as arsenic, beryllium, cadmium, silica, vinyl chloride, nickel compounds, chromium compounds, coal products, mustard gas, and chloromethyl ethers
People who have had radiation therapy to the chest for other cancers are at higher risk for lung cancer, particularly if they smoke. Examples include people who have been treated for Hodgkin disease or women who get chest radiation after a mastectomy for breast cancer. Women who have radiation therapy to the breast after a lumpectomy do not appear to have a higher than expected risk of lung cancer.
Air pollution: in cities, air pollution (especially near heavily trafficked roads) appears to raise the risk of lung cancer slightly. This risk is far less than the risk caused by smoking, but some researchers estimate that worldwide about 5% of all deaths from lung cancer may be due to outdoor air pollution.
Personal or family history of lung cancer
If you have had lung cancer, you have a higher risk of developing another lung cancer.
Brothers, sisters, and children of people who have had lung cancer may have a slightly higher risk of lung cancer themselves, especially if the relative was diagnosed at a younger age. It’s not clear how much of this risk might be due to shared genes among family members and how much might be from shared household exposures (such as tobacco smoke or radon).
Researchers have found that genetics seems to play a role in some families with a strong history of lung cancer.
Once again, there is no point in worrying about risk factors you cannot change. There is a screening test for lung cancer for people who are current or former smokers. More about that in another post.
Colorectal Cancer
Colorectal cancer is the fourth most common cancer in the U.S. The incidence of colorectal cancer is about 38 per 100,000 people per year in the U.S. This means that 4 one hundredths of one per cent of people in the U.S. get colorectal cancer every year. The lifetime risk of getting colorectal cancer is about 4% of people in the U.S. Overall, 35% of people who have colorectal cancer eventually die from it giving an overall cure rate of 65%. The risk of death from colorectal cancer is very dependent on the stage of cancer when it is diagnosed. If colorectal cancer is diagnosed when it is localized, the cure rate is 91%. If it is diagnosed when it has already spread to other parts of the body, the cure rate is 15%.
These are exactly the same modifiable risk factors for breast cancer and prostate cancer. Improving diet, maintaining a normal weight, limiting or eliminating alcohol consumption, and not smoking or quitting smoking decreases population risk of three different cancers.
Risk Factors you cannot change
Age. Almost all colorectal cancers occur after the age of 45 and the vast majority of these occur over the age of 50..
Because chance of cure of colorectal cancer is so much greater when diagnosed at an early stage, screening for colorectal cancer can make a big difference. More about this in another post.
Melanoma Skin Cancer
Melanoma of the skin is the 5th most common cancer in the U.S. It is necessary to specify melanoma of the skin, because melanoma can also occur in the retina of the eye or in any other organ that contains melanocytes (pigment cells). These non-skin melanomas are fortunately rare. The incidence of melanoma of the skin is about 23 per 100,000 people per year or 2 one hundredths of 1 per cent per year. Of those people who develop melanoma of the skin, 6.3% eventually die from it, giving a cure rate of 93.7%. The lifetime risk of getting melanoma is about 2 per cent of people in the U.S.
What do skin melanomas look like?
Warning Signs
a new spot on the skin or a spot that is changing in size, shape, or color.
a spot that looks different from all of the other spots on your skin (known as the ugly duckling sign).
The ABCDE rule.
A is for Asymmetry: One half of a mole or birthmark does not match the other.
B is for Border:The edges are irregular, ragged, notched, or blurred.
C is for Color:The color is not the same all over and may include different shades of brown or black, or sometimes with patches of pink, red, white, or blue.
D is for Diameter:The spot is larger than 6 millimeters across (about ¼ inch – the size of a pencil eraser), although melanomas can sometimes be smaller than this.
E is for Evolving: The mole is changing in size, shape, or color.
Exposure to ultraviolet (UV) rays is a major risk factor for most melanomas. Sunlight is the main source of UV rays. Tanning beds and sun lamps are also sources of UV rays.While UV rays make up only a very small portion of the sun’s rays, they are the main cause of the damaging effects of the sun on the skin. UV rays damage the DNA (genes) inside skin cells. Skin cancers can begin when this damage affects the DNA of genes that control skin cell growth.
The pattern and timing of the UV exposure may play a role in melanoma development. For example, melanoma on the trunk (chest and back) and legs has been linked to frequent sunburns (especially in childhood). This might also have something to do with the fact that these areas aren’t constantly exposed to UV light. Some evidence suggests that melanomas that start in these areas are different from those that start on the face, neck, and arms, where the sun exposure is more constant.
Sunscreen
High protection value sunscreens do prevent sunburn, but paradoxically, people who use high protection sunscreens have an increased risk of skin melanoma. Does that mean sunscreens cause melanoma? No, it means that people who use high protective value sunscreens and apply them frequently are more likely to purposely spend time in the sun (sun bathing). The increased ultraviolet exposure overwhelms the protective value of the sun screen. Avoiding sun bathing and using high protective sun screen when you are working outdoors, as well as wearing a hat and protective clothing is the best way to reduce your population risk of skin melanoma (as well as other types of skin cancers.
Be Vigilant
Be aware of the warning signs above. If you have a mole or a skin lesion that meets any of the warning sign criteria, it is worth a trip to the doctor to check it out.
Risk Factors you can’t do anything about
Moles
A mole (also known as a nevus) is a benign (non-cancerous) pigmented tumor. Babies are not usually born with moles; they often begin to appear in children and young adults.
Having many moles: Most moles will never cause any problems, but someone who has many moles is more likely to develop melanoma.
Atypical moles (dysplastic nevi): These moles look a little like normal moles but also have some features of melanoma. They are often larger than other moles and have an abnormal shape or color. (See Signs and Symptoms of Melanoma Skin Cancer for descriptions of how moles and melanomas look.) They can appear on skin that is exposed to the sun as well as skin that is usually covered, such as on the buttocks or scalp. Dysplastic nevi often run in families. A small percentage of dysplastic nevi may develop into melanomas. But most dysplastic nevi never become cancer, and many melanomas seem to arise without a pre-existing dysplastic nevus.
Dysplastic nevus syndrome (atypical mole syndrome): People with this inherited condition have many dysplastic nevi. If at least one close relative has had melanoma, this condition is referred to as familial atypical multiple mole and melanoma syndrome, or FAMMM. People with this condition have a very high lifetime risk of melanoma, so they need to have very thorough, regular skin exams by a dermatologist (a doctor who specializes in skin problems). Sometimes full body photos are taken to help the doctor recognize if moles are changing and growing. Many doctors recommend that these patients be taught to do monthly skin self-exams as well.
Congenital melanocytic nevi: Moles present at birth are called congenital melanocytic nevi. The lifetime risk of melanoma developing in congenital melanocytic nevi is estimated to be between 0 and 5%, depending on the size of the nevus. People with very large congenital nevi have a higher risk, while the risk is lower for those with small nevi. For example, the risk for melanoma is very low in congenital nevi smaller than the palm of the hand, while those that cover large portions of back and buttocks (“bathing trunk nevi”) have significantly higher risks
Lots of irregular or large moles. The chance of any single mole turning into cancer is very low. However, anyone with lots of irregular or large moles has an increased risk for melanoma.
Fair skin, freckling, and light hair
The risk of melanoma is much higher for whites than for African Americans. Whites with red or blond hair, blue or green eyes, or fair skin that freckles or burns easily are at increased risk.
Family history of melanoma
Your risk of melanoma is higher if one or more of your first-degree relatives (parents, brothers, sisters, or children) has had melanoma. Around 10% of all people with melanoma have a family history of the disease.
Personal history of melanoma or other skin cancers
A person who has already had melanoma has a higher risk of getting melanoma again. People who have had basal or squamous cell skin cancers are also at increased risk of getting melanoma.
Having a weakened immune system
A person’s immune system helps fight cancers of the skin and other organs. People with weakened immune systems (from certain diseases or medical treatments) are more likely to develop many types of skin cancer, including melanoma.
Being older
Melanoma is more likely to occur in older people, but it is also found in younger people. In fact, melanoma is one of the most common cancers in people younger than 30 (especially younger women). Melanoma that runs in families may occur at a younger age.
Being male
In the United States, men have a higher rate of melanoma than women, although this varies by age. Before age 50, the risk is higher for women; after age 50 the risk is higher in men.
Xeroderma pigmentosum
Xeroderma pigmentosum (XP) is a rare, inherited condition that affects skin cells’ ability to repair damage to their DNA. People with XP have a high risk of developing melanoma and other skin cancers when they are young, especially on sun-exposed areas of their skin.
Bottom Line
These five cancers account for half of the cancer diagnoses made every year in the U.S. There are other less common types of cancer, only a few of which have screening tests to detect them early. I will write about some of those cancers in my coming post on screening for cancer. While everyone worries about cancer, the majority of people in the U.S. will never get cancer. The lifetime overall population risk for a U.S.male of getting any kind of cancer other than skin cancer is 40%. For women, that lifetime risk is 39%. These risks average together people at high risk and people at low risk. Your population risk could be substantially lower (or higher) than this average risk.
We are inundated with information about what increases or decreases our risk of heart disease. In this post I will talk about what risk really means, how we calculate risk, and some things you can do to reduce risk of heart disease. OK, here we go.
Risk: What does it mean?
Although we often talk about individual risk (or luck, which is the same thing) risk really only applies to populations. We know, for example, that in the population of people buying lottery tickets, one person will win the lottery. We know that for certain, but we have absolutely no way of predicting who that person will be. The millions of other people who buy lottery tickets will not win the lottery. The population chance of winning the lottery ranges from one in 42 million to one in 176 million depending on the lottery. Any individual’s chance of winning the lottery though is either 0% or 100%. You either win it or you don’t. The very low population chance just means that there will be millions and millions more people who don’t win.
The same thing is true for risk of heart disease or any other disease. We can define a population that has a certain risk of heart disease, let’s say 15% over ten years. We can be very sure that 15% of that population will develop heart disease. but 85% of those people will not develop heart disease. For any individual, we have absolutely no way of knowing or predicting whether they will or will not develop heart disease. Individual risk is either 0% (you won’t get heart disease) or 100% (you will get heart disease). Even though a population risk of 15% is considered high risk of heart disease, the vast majority of those people will not get heart disease. Their risk is 0%. If you are one of the 15% who gets heart disease then your risk is 100%.
Doctors and other health professionals talk about individual risk, even though there is really no such thing. They do this to try to get people to change their behavior or to convince them to take a medicine. If you successfully change your behavior in a healthier direction or you take a medicine that you were not taking before, you then belong to a different population that has a lower risk of disease. Even though you belong to a lower risk population, your individual risk is still either 0% or 100%.
Relative Risk Reduction vs Absolute Risk Reduction
When research is done on some medicine or other intervention to see if it works, the medicine or intervention is given to one population and a placebo (inactive medicine) to another very similar population and the results are compared. A common way to report how much the intervention reduces the risk of a particular disease compared to the risk in the control group is to report it as relative risk reduction.
Here is a real world example. Eating a handful of nuts per day reduces your risk of heart disease by 20%. That sounds like a lot for a very simple intervention. The problem is that number does not tell you anything about the baseline risk of the population. What we want to know is 20% of what?
Suppose we have determined by a risk calculator that you belong to a population that has a 15% risk of heart disease over ten years. 20% x 15% = 3%. The absolute risk reduction is 3%. That doesn’t sound quite as impressive, does it? What is really important for you to know about a treatment is how much it reduces the risk compared to the baseline risk of the control population; that is, you want to know the absolute risk reduction for the population of people treated compared to the people who are not treated. Often results are not reported that way and you have to calculate it yourself. More about this later on.
How do we calculate the population risk of heart disease?
There are several heart disease calculators that let you know what heart disease risk population you belong to. Although each of them talk about calculating your individual risk of heart disease over the next ten years, what they really mean is that you belong to a population that has that risk. Remember that there is really no way to calculate risk for an individual. Here is a link to a page from Harvard Health Publishing that lets you try out each of three different risk calculators: Heart Attack Risk Calculators.
How to put yourself in a lower risk population for heart disease
In order to calculate absolute risk reduction of any medicine or change in behavior, you first have to calculate the risk of the population you are currently in. Multiplying the relative risk reduction of any change times your current population risk gives you the absolute risk reduction of that change. The higher your current population risk, the greater the absolute risk reduction of any change. That means that the first thing you have to do is to use one the risk calculators in the link above to calculate your current population risk of getting heart disease in the next ten years.
In the examples below I’m going to assume a moderate ten year population risk of heart disease of 9%. Remember that if you are in a population whose risk is higher than that, the absolute risk reduction of each change will be larger.
Things that don’t involve taking medicine
In this post I’m going to focus on things you can do to reduce your population risk of heart disease that don’t involve taking medicines prescribed by your doctor. Medicines that treat high blood pressure or high cholesterol can also lower your population risk of heart disease. That is a discussion better left to you and your doctor, however.
Exercise
Regular exercise, depending on the amount, decreases 10 year risk of heart disease by 31 to 45%. For a moderate population risk of 9%, that translates to an absolute risk reduction of 2.8% (.09 x .31) to 4% (.09 x .45). To get the higher level of absolute risk reduction you have to exercise moderately for 150 minutes a week and do activities that enhance muscle strength twice a week. Simply being active most of the time as opposed to sitting most of the time puts you in a population that has a significant absolute risk reduction, on the order of 2-3%. Exercise level is included in many of the risk calculators. If your population risk includes exercise then you should not count that separately.
Saturated vs unsaturated fat
Despite what we have all been told over the years, the evidence is pretty weak that eating saturated fat increases your population risk of heart disease. On the other hand, eating more unsaturated fats does decrease your absolute risk of heart disease. Most studies show that people who ate the most polyunsaturated fats (vegetable oils) had about a 25% relative risk reduction for heart disease. Using our 9% population example the absolute risk reduction is about 2% (.09 x .25).
Eating fish
Eating fish twice a week reduces your relative population risk by 16%. Using our 9% population risk example, that translates to an absolute risk reduction of a little over 1% (.09 x .16).
Eating nuts
As I mentioned at the beginning of this post, eating a handful of tree nuts (cashews, pecans, almonds) reduces the relative population risk by about 20%. In our 9% population risk example, the absolute risk reduction is about 2% (.09 x .20).
Increasing dietary fiber
Fiber in the diet can be increased by eating lots of whole fruits, vegetables and whole grains. Observational studies show this causes a population relative risk reduction of 16%. In our 9% population risk example, the absolute risk reduction is a little over 1% (.09 x .16).
Not Smoking
Smoking cigarettes doubles the relative population risk of heart disease. Using our 9% example, the population absolute risk increase is 9% (1 x .09). Conversely, if you quit smoking your absolute population risk would be cut in half.
Putting it all together
If you make all the exercise and diet changes outlined above, they add up. Lets do the math.
9% ten year risk of heart disease -3% for exercise – 2% for eating more polyunsaturated fats – 1% for eating fish twice a week – 2% for eating a handful of nuts per day – 1% for increasing dietary fiber = 0! Obviously no one has zero risk of heart disease over ten years but this calculation makes the point that doing multiple things that reduce your absolute population risk of heart disease by small amounts add up to a large reduction in your population risk of heart disease. Doing all these things puts you in a population that has less than 1% ten year risk of heart disease. Does that mean you won’t get heart disease if you are a member of this population? No it doesn’t. Remember that it is impossible to calculate the risk for an individual. What being in this population does mean is that only a very few people will get heart disease over the next ten years.
Bottom Line
Risk refers to populations, not individuals. Relative risk reductions are reported in the medical literature most of the time because they are larger and look more impressive. Absolute risk reductions are important to know, because they take into account baseline population risks. If you calculate your baseline population risk by using one of the risk calculators, you can easily calculate absolute risk reduction by multiplying the baseline population risk times the relative risk reduction reported in a study or magazine article. Even though one behavior change produces only a small absolute risk reduction, multiple small absolute risk reductions add up to a big absolute risk reduction.
