Many have come to believe that by living well, eating right and having “good” health indices, they will live longer. A long life is viewed as the reward of exemplary living. Conversely, of course, those who don’t meet what is believed to be healthy are accused of risking an early grave. These mythologies have become popular in our culture, except most are unsupported by decades of the most conscientious evidence.

What is rarely revealed, is that the measures popularly believed to be risk factors are actually not good predictors of our risks for death or disease at all.

The December issue of Archives of Internal Medicine published a study led by researchers at the University of California , San Franciscio examining things believed to contribute to premature death in older women. They examined lifestyles, chronic diseases, medication usage, body measurements and weight, vital signs (blood pressure and resting heart rate) and physical fitness of 17,748 post-menopausal women. Over nine years of followup, they looked to see who died and who didn’t.

None of the lifestyle and risk factors popularly believed to be important actually proved to make a relevant difference except for one.

The only risk factor that had a tenable correlation with increased risk of dying among post-menopausal women was a 50-pack year history of cigarette smoking, which was associated with a nearly 4 times higher risk.

And one of the most popularly-believed risks factor for premature death proved to be associated with a 30% lower mortality among these women — obesity.

Sure, it could be said to be a minor correlation, but if it had supported the dangers of obesity it certainly would have been shouted from the rooftops. But since it didn’t, you never heard about this study.