Birth Control Method Failures

In Human Biology (Chapter 16) there’s a table of data adapted from U.S. Food and Drug Administration data, which lists the approximate failure rates of various contraceptive methods. I’ve always felt that the reported failure rate for condoms of 10-20% seemed awfully high. Condoms are supposed to work, right?

Now there’s an explanation. Apparently, for both condoms and withdrawal there’s a big difference between “perfect use” and “typical use”. If a couple actually uses a condom every time (no exceptions, folks), the annual failure rate is only about 2%. For withdrawal every time, the failure rate is about 4%. The problem is that in the heat of passion some couples “forget”, or convince themselves that not using a birth control method just this once won’t be a big deal. Under these more typical use conditions, the failure rates of condoms and of withdrawal are indeed closer to 20% per year.

If you’re going to rely on these contraceptive methods, don’t cheat!

REFERENCE: R.K. Jones. Better than nothing or savvy risk-reduction practice? The importance of withdrawal. Contraception 79:407-410, June, 2009.

Percocet, Vicodin May be Banned

A federal panel of experts advised the Food and Drug Administration (FDA) this month to ban two popular prescription painkillers, Percocet and Vicodin, from the market. The panel also recommended that the maximum allowable dose of acetaminophen in over-the-counter pills such as Tylenol be reduced from 500 mg to 325 mg. The FDA is expected to accept the panel’s recommendations.

Percocet and Vicodin are comprised acetaminophen plus a narcotic. According to the panel of experts, there is now sufficient evidence to conclude that high doses of acetaminophen over prolonged periods of time can cause liver damage.

It's worth noting that nearly all drugs, even some very good ones, can have unwanted side effects if they are abused.

You can read or see the news reports on the panel’s findings by Googling “FDA”, “Percocet”, and “acetaminophen”.

Getting That Caffeine Buzz

The latest entry into the world of marketing hype - “energy shots”, a mere two ounces of bad-tasting liquid loaded with caffeine. Manufacturers won’t say how much caffeine for proprietary reasons (and probably to add to the drinks’ mystique), but most energy shots are thought to contain on the order of 120-200 mg. That’s the equivalent of one to two ordinary cups of coffee or a 16-oz energy drink.

Energy shots may also contain B-vitamins, amino acids and various plant extracts, but these aren’t likely to give you much of an energy boost despite the products’ claims. And then there’s the cost – upwards of $3 apiece.

If it’s a caffeine buzz you need, what’s wrong with plain-old maximum strength (200 mg) No-Doz? It was your grandfather’s drug of choice nearly 50 years ago for pulling an all-nighter, and it still works. Plus it only costs about 20 cents per dose.

Caloric Restriction and Longevity

It has been known for some time that severe caloric restriction can retard the aging process and prolong the life of a variety of species, from worms to mice. But skeptics of the idea that caloric restriction might also slow the aging process in humans point out that the metabolisms of worms and mice are quite different from that of humans.

Now a new study reports that caloric restriction slows the aging process in primates, too. Macaque monkeys that have been on a calorie-restricted diet (by 30%) for the past 20 years are living longer and are healthier than their age-matched control counterparts. Excluding animals that died of non-age-related causes (accidents for example), 50% of the animals on a normal diet have died of age-related causes, compared to only 20% in the restricted-diet group. The calorie-restricted animals also have fewer age-associated diseases such as diabetes, cancer, and cardiovascular disease. The study is still ongoing.

Wildfires, Evolution, and Ecosystems

Fires set by the forces of nature have existed on the Earth since the dawn of time, and as a result some plants have evolved to survive fires rather well. A few plants even require an occasional fire in order to release their seeds. But here’s an interesting notion; did certain plants evolve to encourage the spread of wildfires once they’ve started? After all, if the plant could survive the fire it might be a good way to kill off the competition. For those of you interested in evolutionary processes, see the recent well-referenced opinion article in the New York Times.

Swine Flu Takes Hold in Argentina

Swine flu just won’t go away. A recent a sharp uptick in the number of deaths from swine flu in Argentina has moved that country into third place for the most swine flu deaths, after Mexico and the United states. And the timing couldn’t be worse; it’s winter in South America, the season when influenza viruses typically spread the easiest. Of special concern is that the death rate in Argentina (1.6%) is more than three times the world average.

We need to keep an eye on this pesky bug. Who knows what it could do in North America NEXT flu season? For the latest information on swine flu (also now called Pandemic H1N1), see the World Health Organization website.

Is Being Overweight a Health Risk?

It depends on the question - a health risk for what? People who are overweight, defined by the U.S. government and the World Health Organization as a Body Mass Index (BMI) of between 25 and 30, apparently do have a slightly increased risk for certain diseases such as diabetes, coronary artery disease and hypertension. But for other parameters, such as risk of death, the evidence is not that clear-cut. In fact, a recent study of over 11,000 Canadian adults reveals that as a group, people who are defined as overweight have a slightly lower risk of death than the normal-weight group, though not by much.

Taking this new mortality data into account and reviewing the graph in the essay in Human Biology, one wonders whether the range of “normal” weight shouldn’t be shifted about 3 BMI to the right. A word of caution, however; the shape of the weight-vs.-risk curve is likely to be different for every disease, age group, etc. It’s probably going to be impossible to come up with a perfect functional definition of overweight, no matter how much we’d like to.