Age-related declines in percentage of lean body mass and total lean to fat mass ratio over time are associated with a higher risk for diabetes among healthy men, according to study results published in the Journal of the Endocrine Society.
Previous studies have reported that during adulthood, fat mass increases and lean body mass decreases, whereas in late life, fat mass also may decline. Lower lean body mass has been found to be related to elevated blood glucose and diabetes. The goal of the current study was to assess the relationship between the change in total lean body mass with aging and the development of diabetes.
The researchers used the Baltimore Longitudinal Study of Aging, a cohort study of community-dwelling healthy men and women aged 20 to 98 years who underwent extensive evaluations at regular intervals (average, 2.5 years). Total body composition was assessed using dual-energy x-ray absorptiometry and time-dependent lean body mass measures were updated at each follow-up visit. Individuals were observed overnight on a research ward and after a 10-hour overnight fast, they received an oral glucose tolerance test to assess glycemic status.
The study cohort included 871 men and 984 women without diabetes (mean baseline age, 58.9±17.3 years). During a median follow-up of 7 years (range, 1-15 years), there were 134 incident cases of diabetes.
Among both men and women, a higher quartile of percentage of total lean body mass at baseline was associated with significantly younger age and lower body mass index, total body weight, total fat body mass, fasting glucose and 2-hour glucose levels, and prevalence of diabetes (all P <.05).
Statistical analyses showed that among men in the highest quartile of percentage of total lean body mass, the risk of developing diabetes was 54% lower compared with men in the lowest quartile (hazard ratio [HR], 0.46; 95% CI, 0.22-0.97; P =.01). Similar findings for percentage of leg lean mass were observed in men when comparing the highest vs lowest quartiles (HR, 0.38; 95% CI, 0.15-0.96). In addition, men in the highest vs lowest quartile of lean to fat mass ratio had a 61% lower risk of developing diabetes (HR, 0.39; 95% CI, 0.17-0.89), but this association was no longer significant after further adjustment for baseline height and weight.
For women, there was no significant association between percentage of total lean body mass quartile and incident diabetes. However, in both men and women, the researchers noted an unexpected finding: a relatively higher quartile of absolute total lean body mass was significantly associated with a higher risk of developing diabetes, even after accounting for total fat mass measures.
The researchers acknowledged several limitations to the study, including those related to the method of body composition assessment, lack of repeated measures of lean body mass for all study participants, and missing data on physical activity measures and glycemic control in some individuals.
“Age-related declines in percentage of total lean body mass were related to higher risk of incident diabetes in healthy community-dwelling men up to 15 years later, in part due to differences in anthropometrics,” concluded the researchers.
Kalyani RR, Metter EJ, Xue Q-L, et al. The relationship of lean body mass with aging to the development of diabetes [published online April 30, 2020]. J Endocr Soc. doi:10.1210/jendso/bvaa043