As more worksite wellness programs rely on biometric screening data to identify health risks in employees, it’s important to understand which tests offer the most accurate results. To screen for obesity, many employers measure body mass index (BMI) or waist circumference.
BMI is based on a formula that measures height and weight and places a person in one of four categories:
- Underweight: BMI below 18.5
- Normal: BMI ranging between 18.5 and 24.9
- Overweight: BMI between 25 and 29.9
- Obese: BMI of 30 or higher
While BMI can be a useful measurement, it often doesn’t tell the whole story because it cannot account for the following:
- Muscle tone. An individual can have a high BMI despite having little body fat, because muscle tissue pushes up their weight. Think football players and bodybuilders.
- Activity level. Someone who is inactive, with a higher percentage of body fat, can still have a BMI in the normal range. This can be due to low levels of muscle and bone, as sometimes seen in the elderly, those in poor shape and even those who are sick.
- Body type. The location of body fat makes a difference in health. If a person is an “apple” shape, with higher amounts of abdominal fat, that’s riskier. Fat that settles on the hips and thighs, creating more of a “pear” shape, isn’t as potentially harmful.
- Age. Ideal BMI shifts with age. Studies have shown that those who are a little bit heavier tend to have higher survival rates than lean people, though the reasons for this are still unclear. Age is not a license to have a BMI of, say, 30, however.
- Ethnicity. For some ethnic groups, health risks increase at a lower-than-standard BMI. In particular, Asian-Americans tend to develop health risks at significantly lower BMIs than whites.
With these limitations in mind, what can you do to ensure a better understanding of your employees’ health risks? Many employers also consider waist circumference.
Waist circumference is measured by locating the upper hip bone and placing a measuring tape around the abdomen. For men, the desired measurement is 40” or less. For women, it’s 35” or less. Measuring weight circumference provides an important data point. When an individual has a normal BMI but a significant amount of abdominal fat, potential health risks can be identified.
What is it about abdominal fat that makes it a strong marker of disease risk? While no one likes fat of any kind, this sinister fat crowds your liver and other abdominal organs. Also known as visceral fat, it is metabolically active…and not in a good way. Visceral fat releases fatty acids, inflammatory agents and hormones that can elevate LDL cholesterol (the bad kind), triglycerides, blood glucose and blood pressure. The result is a higher risk of Type 2 diabetes, heart disease and liver disease. These kinds of risks might be overlooked if only BMI is measured.
So if screenings are a part of your worksite wellness strategy, it‘s wise to consider using a combination of BMI and waist circumference as one way to more accurately assess risk factors. Waist size can serve as a simple way for individuals to assess their risk for cardiac disease among other risks. Plus, waist measurements can serve as a wake up call for those who could benefit from a “next steps” discussion with a primary care physician, or an easy way for individuals to see their progress toward better health.