Is BMI Still a Reliable Health Metric in Aging Populations? Study Provides Insights - Video

Body mass index (BMI) is key method for measuring a person's weight status, and defining if they have normal weight, overweight, or obesity. However, new research to be presented at this year’s European Congress on Obesity shows that people with obesity at similar BMIs display significant differences in body composition in different body compartments according to their age group, such as higher body fat especially in central regions and lower muscle mass in arms and legs.

Obesity is a major health problem characterised by an excessive accumulation of body fat (BF) that can also co-exist with a reduction in lean mass (LM). In people with obesity, little is still known about the changes in fat and lean masses across the lifespan. Thus the authors, in this new study, aimed to analyse the differences in the total and segmental body composition between age groups.

A total of 2,844 adults of both

sex and a Body Mass Index (BMI) of 25 kg/m² and above underwent body composition assessments by means of Dual-energy X-ray Absorptiometry (DXA). The sample was categorised into three different age groups: ‘Young-age’ (20–39 years), ‘Middle-age’ (40–59 years), and ‘Older-age’ (60–79 years) adults that were compared with each other after being matched by body weight and BMI.

The males showed an increasing trend in total BF percentage and a decreasing total LM, from the younger to older groups, while females maintained similar values for these total compartments across the three age groups.

However more interestingly, participants in the middle- and older-age groups of both sexes, showed higher trunk fat percentage and lower appendicular lean mass with respect to the young-age group, revealing higher abdominal fat and lower muscle mass in arms and legs, despite the fact that all age groups in this study were of similar BMIs

The authors hence, explain that this redistribution may have major negative health consequences – such as low-grade chronic inflammation, insulin resistance, and increase in the risk of several cardiometabolic diseases – without significant changes in BMI.

Ref: European Congress on Obesity (ECO2025).18-Mar-2025