As part of our wellness initiative at the Oklahoma Medical Research Foundation, we've begun offering all employees free biometric screenings. Biometric screening, a term that was new to me until recently, is a sort of quick assessment that covers a variety of tests and measurements that serve as basic indicators of your health. I recognized many of these tests and measurements — blood pressure, cholesterol, blood glucose levels, body mass index — from my annual physical exam.
At OMRF, we've had extremely high levels of participation in the screenings. That's great news, as it signals that our employees care about their well-being and are eager to get an accurate picture of their physical health.
Not surprisingly, the screenings have also provoked a good deal of discussion, particularly about body mass index, or BMI. Several people have questioned whether BMI is an accurate way to assess a person's body fat levels. Others have wondered if it's a good predictor of future health. I didn't know the answers, so I figured I'd ask you.
Dr. Prescott prescribes
BMI is computed by taking a person's weight in kilograms and dividing by the square of his or height in meters (don't worry — there won't be a quiz). More simply put, it's a ratio of a person's height to weight that serves as a rough proxy of body-fat percentage.
Under current guidelines, anyone with a BMI 25 or more is considered overweight, while 30 or above qualifies as obese. A 2007 U.S. National Health and Nutrition Examination Survey found that 67 percent of Americans met the definition of overweight or obese.
So what does this mean?
Research has found that overweight and obese individuals are at a higher risk for a wide variety of health problems, ranging from hypertension and osteoarthritis to type 2 diabetes, coronary heart disease and stroke. They also have higher rates of disability.
But while obese people as a whole have a higher mortality rate than those in the normal range, those with the lowest obesity level (BMI less than 35) or who were merely overweight were at no greater risk for death than normal-weight people.
Like any piece of data, BMI should not be viewed in a vacuum. If your other numbers (cholesterol, blood pressure and blood sugar) are OK, a BMI slightly above normal levels is no reason to panic.
Remember, too, that BMI is an estimate. It may overestimate body fat in highly muscled individuals (think Adrian Peterson). If you fall into that highly muscled athlete category — you lucky dog, you — it may falsely characterize you as overweight or obese.
Remember, too, that all fat is not created equal. The fat that forms around your belly is most dangerous, as it correlates strongly with heart disease and stroke. So regardless of your BMI, it's important to look at your waistline — less than 40 inches for men and 35 for women is recommended — and your waist-to-hips ratio.
BMI is neither a perfect measure of leanness nor a faultless predictor of health outcomes. But it does serve as a useful starting point for asking questions about your health. And the more you know, the better equipped you'll be to make smart choices when it comes to diet and exercise.
Dr. Stephen Prescott, a physician and medical researcher, is president of the Oklahoma Medical Research Foundation. Adam Cohen is a marathoner and OMRF's senior vice president and general counsel.