BMI Proves Unreliable in Certain Populations

The use of body mass index is widespread among scientists and clinicians looking to determine overweight and obesity levels among various populations. However, researchers from the Deakin University IMPACT Strategic Research Centre in Geelong, Australia, believe this approach has flaws.

To determine this, the researchers analyzed body fat percentage and BMI of 2,491 Australians aged 20-96. These values were compared with “internationally recognized BMI cut-points for defining underweight, overweight and obesity,” the authors explained. Upon examining the findings, the researchers uncovered a discrepancy in obesity measures based on BMI among men. Female BMI and body fat percentage measures appeared to line up somewhat more accurately. Specifically, they found that 80.1% of women and 53.9% of the men studied who were considered obese based on body fat percentage were classified as such using BMI.

“As a corollary, 19.9% of women and 46.1% men with high %BF were overlooked as being obese according to BMI criteria,” explained the authors.

The authors also noted that the most significant underestimation of obesity based on BMI was seen among young and elderly men.

The researchers also reported that “for both sexes, the prevalence of underweight using a BMI threshold may underestimate the true extent [of obesity] in the population.”

The study is published in BMC Obesity (2014; 1[9]).

PHOTOGRAPHY: Jenny