An article from Harvard Health Publishing
Body mass index, or BMI, has long been the standard tool for assessing weight status and health risk. A calculation of your size that takes into account your height and weight, BMI is frequently used because it’s a quick, easy, and inexpensive measurement tool. Yet, it lacks any assessment of how much fat a person has or how it’s distributed throughout the body, both of which are key indicators of metabolic health. A recent study published in The BMJ analyzed different measures of body shape — more specifically, of central or abdominal fat — to determine which measures were most predictive of premature death.
Abdominal fat associated with higher risk of death
Researchers in this study analyzed the following measurements of central fatness: waist, hip, and thigh circumference; waist-to-hip ratio; waist-to-height ratio; waist-to-thigh ratio; body adiposity index (which incorporates hip circumference and height); and a body shape index (calculated from waist circumference, BMI, and height).
They found that a larger hip and thigh circumference (sometimes referred to as a pear shape) were associated with lower risk of death from all causes. All other measures, which indicated centrally located fat (sometimes called an apple shape), were associated with a higher risk of death. That is, the more abdominal fat a person has, the higher their risk of dying from any cause.
What do these results mean?
These findings tell us that not only does the total amount of body fat determine health risk, but also the location of that fat on a person’s body. Prior research has shown that abdominal obesity is more strongly associated than overall obesity with cardiovascular risk factors such as increased blood pressure, elevated blood triglyceride levels, and type 2 diabetes. Studies have shown it’s even linked to dementia, asthma, and some cancers.
Fat located around the abdomen, particularly visceral fat surrounding the liver and internal organs, is highly inflammatory and metabolically disruptive: it releases inflammatory molecules that contribute to insulin resistance, type 2 diabetes, and ultimately cardiovascular disease. In contrast, fat located at the hips and thighs is protective. These protective effects include an association with lower total cholesterol, LDL (or bad) cholesterol, triglycerides, arterial calcification, blood pressure, blood glucose and insulin levels, and higher sensitivity to insulin.
Taken together, these findings demonstrate the importance of using BMI along with measurements of abdominal fat to fully assess health risk.