Friday, July 27, 2007

Obesity in Close Mutual Friends

If your closest friend becomes obese your risk of obesity goes up dramatically, according to researchers. And it was not just a matter of the friends eating the same foods, because the relationship holds even if the friends are separated geographically. Your risk also goes up if you have a sibling or a spouse who becomes obese, though the effect is not as great as between best friends.

How might social relationships affect obesity? Researchers speculate that when a person who becomes obese is already a close mutual friend, a sibling, or a spouse, one may tend to perceive obesity as more acceptable than if the person is a total stranger. Close mutual friends may also influence a person’s eating habits, even if the friends are not always together.

The data also offer a clue for why many of the most successful weight-loss programs are those that offer peer support. By modifying a person’s social network to include people who are also trying to lose weight, one’s view of normal and acceptable begins to change. The bottom line is that obesity is not just a medical problem with genetic roots, but also a public health problem with social causes. Understanding obesity will require a full understanding of both.

Tuesday, July 24, 2007

Birth Control Pills on Campus

The cost of prescription birth control pills is likely to increase dramatically on many college campuses this fall. Manufacturers of birth control pills routinely used to sell the pills to college health clinics at steeply discounted rates in an effort to win future customers. And in an effort to encourage responsible behavior and make birth control readily available, many colleges passed those savings directly on to the users. But according to an article in this week's The Chronicle of Higher Education (July 27, pp.A31-A32), changes in Medicaid reimbursement rules have made it too costly for the manufacturers to continue this practice. As a result, some college women will find that prices have gone up as much as 5-fold on campus this fall – to the same price they’d pay at a commercial pharmacy.

The American College Health Association is lobbying to have the Medicaid reimbursement ruling reversed, at least for college campuses, arguing that it was an unintended consequence of a change in the law. But that’s not likely to happen by the time students return to campus this fall.

Friday, July 20, 2007

Bird Flu Preparedness in the U.S.

This week the federal government released a report card on U.S. preparedness for a bird flu pandemic. The report comes just over a year after the government issued their National Strategy for Pandemic Influenza Implementation Plan. The new report stresses that although most of the original plan has already been put into place, areas of weakness include a limited capacity to detect an outbreak, and the possibility that hospitals would be overwhelmed by the large number of persons who might become infected.

The report also notes that media attention to bird flu seems to have died down. And yet, almost as many people have died of the disease in 2007 as in each of the previous two years. Do we just have short attention spans?

The complete report can be accessed at

Thursday, July 19, 2007

Would You Eat Your Placenta?

It’s called placentophagy (or placentophagia). There are no statistics on the percentage of new moms who do it, but there are a surprising number of references to it on the Web. There are even recipes for preparing placenta – placenta pills; placenta blended with V8 juice; placenta sauteed with olive oil and garlic; placentaburger; placenta lasagna; even placenta smoothies! Maybe I'm just not adventurous, but I think I'll pass on this one.

Proponents argue that most mammals eat their placenta (true, but what’s the relevance?) and that eating the placenta confers nutritional or health benefits to the new mom, including reduction of post-partum pain, depression and bleeding (largely untested). There are lots of anecdotal testimonials from new moms who say they feel just great after eating portions of their placenta. But hey, if you’re willing to chow down on your placenta in the first place based solely on your belief system, is it any surprise that you would report feeling better afterwards? There are even fathers trying it. Call me a skeptic, but what would it do for the father?

Eating raw human blood products could increase the risk of contracting hepatitis B, C, and HIV. And anyone thinking about frying up some placenta for its alleged health benefits should know that there are plenty of other ways (pharmaceutical drugs, hormones, and vitamin pills) to reduce post-partum pain, bleeding, and depression, or to maintain good post-partum nutrition.

Instructors could use this topic to explain the difference between belief and scientific evidence; between anecdote and statistically significant data. They could also have students research the topic, bring in statements about the health benefits of eating the placenta, and then discuss (or vote) on whether the statements are closer to “belief/anecdote” or to “science/data” so they can begin to see the differences. Who knows, they might even find that there is some good scientific evidence out there that I am not aware of.

Tuesday, July 17, 2007

Antidepressants and Childhood/Adolescent Suicide

One of the most basic rules of medicine is expressed in the Latin phrase primum no nocere – first do no harm. So here’s an real-life ethical dilemma for you; if antidepressants such as Prozac have the potential to cause harm to some patients, is it still okay for a physician to prescribe them if, in the balance, the drugs help more patients than they harm? That, apparently, is the dilemma now faced by the Food and Drug Administration (FDA).

Several years ago a careful analysis of trials of antidepressants reported that Prozac and the other drugs in its class (known as selective serotonin reuptake inhibitors, or SSRIs) increase the risk of spontaneously reported suicide-related events in children and adolescents. Accordingly, in 2003 the FDA issued a health-advisory that children and adolescents on Prozac might be at “increased risk of suicidal thinking and behavior”, and ordered that a black box warning be placed on all prescriptions. (The label is called a “black-box” warning because of its black border).

Physicians and parents took the warning seriously. From 2003 to 2005 the number of prescriptions for SSRIs for childhood and adolescent depression fell by 50%. This should have been a good thing, right? Perhaps not. New data shows that after 10 years of decline, the suicide rate in children and adolescents increased 18% in 2004, the most recent year for which there are data (Annual Summary of Vital Statistics: 2005. Pediatrics 119:345-360, 2007).

The data support the hypothesis that the risk of not prescribing Prozac for child and adolescent depression may, in fact, be more harmful than prescribing it. But we need to be careful to not over-interpret the data, for correlation does not prove causation. Now at least we know what the question is. Careful attention to study protocols will be needed to sort this one out, because suicidal thinking and behavior are difficult to classify at best.

Monday, July 9, 2007

The Immune System and Cancer

The July 2007 issue of Scientific American has an informative article on the role of the immune system in the development and spread of cancer. (A Malignant Flame. Scientific American July 2007, pp. 60-67). The article describes how our thinking has changed over the past decade or so.

It turns out that although the immune system sometimes helps to prevent the development and spread of cancer, at other times the immune system actually contributes to cancer development. This is particularly true of the non-specific immune defense mechanisms (they call it the “innate” immune system). The next generation of anti-cancer drugs may include some anti-inflammatory therapies, as well as traditional chemotherapies. Instructors with a special interest in cancer may wish to incorporate information in the article into their discussion of Chapter 18 – Cancer – in Human Biology, 5th ed.

The article points out that the immune system is also increasingly being implicated as a possible player in a whole host of chronic diseases, including heart disease, diabetes, Alzheimer’s disease, and schizophrenia and depression. More information is likely to be forthcoming on the role of the immune system in these diseases in the years to come.

Thursday, July 5, 2007

A Biofuel Made From Fructose

Scientists can now make a fuel for your car from fructose, the sugar found in fruits such as apples and pears. The new fuel, called dimethlyfuran, has several advantages over ethanol: it has a higher energy content than ethanol, it repels water so that it is not diluted by moisture in the air, and it has a higher boiling point than ethanol so it stays a liquid more readily in the tank ethanol. The process for making the new experimental fuel is described in the June 21 issue of Nature.

However, like ethanol, the new fuel still has one distinct disadvantage; the starting material is food. Call it an incremental advance over ethanol if you like, but what we’d really like to do is to be able to make biofuels from the leftovers, not the food crops themselves. The real advance will come when we can make fuel for our cars from grass clippings, wheat chaff, or wood chips, reserving the apples and corn for our own consumption. That’s been a harder nut to crack, but researchers are working on it.

The U.S. Department of Energy has set a target of 30% of the 2004 demand for gasoline to be replaced by biofuels by 2030. Can we do it? This would be an exciting time to be a young researcher in the area of biofuels development. There may be some new career opportunities ahead for students interested in this and other environmental issues…