Association Between Trunk Fat Mass Index and Diabetes in a Multinational Population

To examine the cross-sectional association between trunk fat mass index (TFMI) and diabetes across individuals within the same body mass index (BMI [calculated as the weight in kilograms divided by the height in meters squared]) categories in a multinational population.

We harmonized and pooled data on 57,764 individuals aged 40 years and older from the United Kingdom, the United States, and South Korea. Trunk fat mass imaging was performed using a dual-energy X-ray absorptiometry device during 2015-2023 in the United Kingdom, 2011-2018 in the United States, and 2008-2011 in South Korea. The prevalence of diabetes was derived from the self-reported medical history. Additionally, plasma biochemistry analyses were conducted to update the number of participants with diabetes.

Among participants classified as having a normal weight based on BMI, the relative risks (RRs) of diabetes increased from TFMI quintiles 1 to 5 with the linear trend (P<.001). The risk of diabetes among individuals in TFMI quintile 5 was around 3 times greater than those in quintile 1 (men-RR, 3.06; 95% confidence interval [CI], 2.17-4.34; women-3.35; 95% CI, 2.08-5.39). This significant linear trend (P<.001) in RRs was also present in overweight and obese individuals (overweight men-RR, 1.92; 95% CI, 1.50-2.47; overweight women-RR, 2.25; 95% CI, 1.73-2.91; obese men-RR, 2.47; 95% CI, 1.83-3.35; obese women-2.79; 95% CI, 2.04-3.83).

Within a specific BMI category, individuals with a high trunk fat mass are more likely to experience diabetes compared with those with lower levels of central fat.