Study analyzes how BMI and waist circumference affect mortality in older adults

In a Journal of the American Geriatrics Society analysis of nationally representative data from 6,905 US adults aged 65 or older followed between 2011–2024, higher body mass index (BMI) was associated with lower mortality risk, whereas higher waist circumference, a marker of abdominal obesity, was independently associated with higher mortality risk after accounting for BMI.

Compared with normal weight, overweight males and males with class I and II obesity (BMI of 30 to less than 40 kg/m2) had 46% and 51% lower risks of mortality, respectively. Additionally, a high waist circumference was also associated with a 24% higher mortality risk in males. Similar patterns were observed in females.

When BMI and waist circumference were evaluated together, being overweight was associated with lower mortality risk regardless of waist circumference among males. Class I and II obesity also remined associated with lower mortality risk exclusively among males with elevated waist circumference. In contrast, being underweight, regardless of waist circumference, and having normal BMI with elevated waist circumference were both associated with higher mortality risk in both males and females.

BMI and waist circumference provide complementary information about health risk in older adults. Our findings suggest that considering both measures together, rather than relying on BMI alone, may improve mortality risk assessment and support more informed clinical decision-making."

Bryan Blissmer, PhD, study co-author, University of Rhode Island