Watch Your Waist Not Just Your Weight

When we talk about obesity it seems like we're most often talking about Body Mass Index (BMI). Certainly, I've been doing a lot of talking and writing about it. There's another tool that doctors use to assess weight that I've talked about, just not quite as much: Waist-to-Hip Ratio (WHR).

We know that those with a higher waist-to-hip ratio are at a higher risk for heart disease as well as other problems, but it appears that they're simply at a higher risk for death, as well.

An international group of researchers looked at the information gathered in a very large study called European Prospective Investigation into Cancer and Nutrition (EPIC) (New England Journal of Medicine 2008;359:2105-20). This study included almost 340,000 people from 10 different countries and lasted about 10 years. Those people who participated in the study completed a questionnaire that asked for information regarding their medical history and lifestyle, which included whether they smoked or drank alcohol (and, of course, how much). Their height, weight, waist circumference and waist-to-hip ratio also were recorded.

The researchers compared the BMI and WHR of those people who died during the course of the study with those who did not die. Consistent with other studies of Body Mass Index and the risk of death, those who were underweight (BMI less than 18.5) and those who were overweight, obese or severely obese (BMI over 25) had higher risks of death.

Similarly, waist circumference and WHR, taken alone, also carried a higher risk of death for those who were under- or overweight.

But when Body Mass Index and Waist-to-Hip Ratio/waist circumference were considered together, it became clear that the waist is a much stronger indicator of risk of death than we ever thought. For any given BMI, they found, an increase in a person's waist circumference of as little as 5 centimeters (almost 2 inches) meant their risk of death went up by 17 percent for men and 13 percent for women.

Further, those people with the highest waist-to-hip ratio, compared with those with the lowest, had a 79 percent higher risk of death for men; women's risk increased 53 percent.

Once again, those who are "apple-shaped" are shown to be at higher risk than those who are "pear-shaped." This is independent of your Body Mass Index, however: your BMI can be within the normal range, but if you have a poor Waist-to-Hip ratio score, you are still at a higher risk of death.