Ever wonder why, on average, women live five to 10 years longer than men? This week's Time magazine features an interview with Tom Perls, founder of the New England Centenarian Study at Boston University (and creator of the Web site Livingto100.com). He gives several possible reasons:
First, women tend to develop cardiovascular diseases like heart attack and stroke about 10 years later than men. (Women are particularly vulnerable starting around their 70s or 80s, compared with 50s or 60s for men.) Researchers used to think this was because of estrogen, but now there are a couple of alternative theories. One is that women tend to have lower levels of iron in their blood than men. As someone who's always diagnosed as borderline anemic, I thought that'd be a bad thing -- but according to Perls, "iron plays a very important part in the reactions in our cells that produce damaging free radicals, which glom onto cell membranes and DNA and may translate into aging of the cell." Interesting.
Second, women have two X chromosomes. The article provides a longer explanation, but basically this means that in any given cell, genes have a choice of two chromosomes on which to express themselves. (In other words, in some cells, a gene will express itself on chromosome No. 1, and in others, it will express itself on No. 2.) If one version is more beneficial than the other, the cells that contain it are going to proliferate as cells that don't die off. Think of it as a battle for the survival of the fittest going on in your own body, where you end up the winner.
Third, even before they get old enough to think about heart attacks, men are engaging in riskier behavior (partially thanks to a "testosterone storm" that hits in the late teens and early 20s). They're more likely to drive without seat belts, drink more alcohol and get in bar brawls -- and in general they smoke more and eat higher-cholesterol foods than women do (though from my understanding the link between dietary and blood cholesterol has been called into serious question recently). Also, they deal less well with stress. Not exactly a recipe for a long and healthy life.
Luckily, though, there's good news out there for anyone born with XY chromosomes: According to Perls, 70 percent of your longevity is determined by your behaviors, not your genes. But then again, for some people the idea of transforming into a vegan yoga addict might be more upsetting than a few lost years.