Why take a drug, herb or any other supplement? It’s usually because we believe the substance will do something desirable, and that we’re doing more good than harm. To be truly rational we’d carefully evaluate the expected risks and benefits, estimate the overall odds of a good outcome, and then make a decision that would weigh these factors against any costs (if relevant) to make a conclusion about value for money. But having the best available information at the time we make a decision can still mean decisions turn out to be bad ones: It can be that all relevant data isn’t made available, or it can be that new, unexpected information emerges later to change our evaluation. (Donald Rumsfeld might call them “known unknowns.”)
As unknowns become knowns, risk and benefit perspectives change. Clinical trials give a hint, but don’t tell the full safety and efficacy story. Over time, and with wider use, the true risk-benefit perspective becomes more clear, especially when large databases can be used to study effects in large populations. Epidemiology can be a powerful tool for finding unexpected consequences of treatments. But epidemiologic studies can also frustrate because they rarely determine causal relationships. That’s why I’ve been following the evolving evidence about calcium supplements with interest. Calcium supplements are taken by almost 1 in 5 women, second only to multivitamins as the most popular supplement. When you look at all supplements that contain calcium, a remarkable 43% of the (U.S.) population consumes a supplement with calcium as an ingredient. As a single-ingredient supplement, calcium is almost always taken for bone health, based on continued public health messages that our dietary intake is likely insufficient, putting women (rarely men) at risk of osteoporosis and subsequent fractures. This messaging is backed by a number of studies that have concluded that calcium supplements can reduce bone loss and the risk of fractures. Calcium has an impressive health halo, and supplement marketers and pharmaceutical companies have responded. There are pills, liquids, and even tasty chewy caramel squares embedded with calcium. It’s also fortified in foods like orange juice. Supplements are often taken as “insurance” against perceived or real dietary shortfalls, and it’s easy and convenient to take a calcium supplement daily, often driven by the perception that more is better. Few may think that there is any risk to calcium supplements. But there are now multiple safety signals that these products do have risks. And that’s cause for concern. (more…)
Dr. H. Gilbert Welch has written a new book Over-diagnosed: Making People Sick in the Pursuit of Health, with co-authors Lisa Schwartz and Steven Woloshin. It identifies a serious problem, debunks medical misconceptions and contains words of wisdom.
We are healthier, but we are increasingly being told we are sick. We are labeled with diagnoses that may not mean anything to our health. People used to go to the doctor when they were sick, and diagnoses were based on symptoms. Today diagnoses are increasingly made on the basis of detected abnormalities in people who have no symptoms and might never have developed them. Overdiagnosis constitutes one of the biggest problems in modern medicine. Welch explains why and calls for a new paradigm to correct the problem. (more…)
A recent story on NPR accused the drug manufacturer Merck of inventing a disease, osteopenia, in order to sell its drug Fosamax. It showed how the definition of what constitutes a disease evolves, and the role that drug companies can play in that evolution.
Osteoporosis is a reduction in bone mineral density that leads to fractures. The most serious are hip fractures, which require surgery, have complications like blood clots, and carry a high mortality. Many of those who survive never walk again. Vertebral fractures are common in the osteoporotic elderly and are responsible for dowager’s hump and loss of height. There is also an increased risk of wrist and rib fractures.
Bone density tends to decrease with age. Postmenopausal women are particularly susceptible to osteoporosis when their production of estrogen declines. The risk is increased in people taking corticosteroids and in people with certain diseases like rheumatoid arthritis. Other risk factors are European or Asian ancestry, smoking, excess alcohol, a family history of fractures, vitamin D deficiency, too much or too little exercise, malnutrition, and low body weight.
When a measurement like bone density varies widely in a population and decreases with age, how can we decide where to draw the line and call it abnormal? When does it become a disease requiring treatment? (more…)
There is a new industry offering preventive health screening services direct to the public. A few years ago it was common to see ads for whole body CT scan screening at free-standing CT centers. That fad sort of faded away after numerous organizations pointed out that there was considerable radiation involved and the dangers outweighed any potential benefits.
Now what I most commonly see are ads for ultrasound screening. In fact, I am sick and tired of finding them in my mailbox and between the pages of my local newspaper. Ultrasound is certainly safe, with no radiation exposure. It sounds like it might be a good idea, but it isn’t.
Life Line Screening advertises itself as “America’s leading provider of quality health screenings.” They offer “4 tests in less than 1 hour – tests that can save your life.” They travel around the country, setting up their equipment in community centers, churches, and YMCAs. For $129 you get ultrasounds of your carotid arteries, your abdominal aorta, your legs, and your heel bone. They mail you your results 21 days later. (more…)