Age-related muscle loss may drive type 2 diabetes risk among men
Older men with sarcopenia are more likely to develop type 2 diabetes during 15 years of follow-up compared with men who have more lean body mass, according to findings published in the Journal of the Endocrine Society.
“We sought to understand whether men or women who had lower lean body mass as they aged were more likely to develop diabetes,” Rita R. Kalyani, MD, MHS, an associate professor of medicine in the division of endocrinology, diabetes and metabolism at Johns Hopkins School of Medicine, told Healio. “We found that, among participants in the Baltimore Longitudinal Study of Aging, who were followed up to 15 years, relatively lower lean body mass with aging was associated with a higher incidence of diabetes among men but not women, and was partially related to body size.”
Kalyani and colleagues analyzed data from 871 men and 984 women without diabetes at baseline who participated in the Baltimore Longitudinal Study of Aging, a study with a median follow-up of 7 years (mean baseline age, 59 years). Participants underwent DXA measurements to assess total body composition, fat mass, fat-free mass and bone mineral content for total body and lower extremities. Participants were stratified by quartiles for each baseline body composition measure, with percentage of total lean body mass quartile cutoffs for men of 43.6% to 62.8%, 62.9% to 67.7%, 67.9% to 72.8% and 72.8% to 91.5%. Percentage of total lean body mass quartile cutoffs for women were 37.3% to 52.24%, 52.34% to 57.6%, 57.6% to 62.2%, and 62.2% to 86.6%. Researchers used Cox proportional hazard models, with age as the time scale, to examine the time to incident diabetes. Lean body mass measurements were updated at each follow-up visit.
During follow-up, researchers observed 134 incident diabetes cases.
Researchers found that men and women with a higher percentage of total lean body mass had lower fasting and 2-hour glucose measurements, and a lower prevalence of prediabetes at baseline (P = .01 for all).
Among men, regression analyses showed that participants in the third quartile of percentage total lean body mass had a 55% lower risk for developing type 2 diabetes (HR = 0.45; 95% CI, 0.22-0.92) and those in the highest quartile had a 54% lower risk for developing diabetes (HR = 0.46; 95% CI, 0.22-0.97) compared with men in the lowest total lean body mass quartile (P for trend = .01). Men in the highest vs. lowest quartile of percentage leg lean mass and lean:fat ratio had a 62% and 61% lower risk for developing diabetes, respectively; however, the relationships were attenuated after accounting for height and weight in analyses.
For women, researchers did not observe an association between percentage of total lean body mass quartile and incident diabetes; however, higher absolute total lean body mass was associated with incident diabetes among women, with similar trends observed among men.
“These divergent findings may be related to limitations of the body composition method, DXA, used in the study,” Kalyani said. ).
Researchers did not observe any associations between muscle strength or quality and incident diabetes.
“Approximately 1 in 4 adults aged 65 years and older has diabetes,” Kalyani said. “Older adults with diabetes have the greatest burden of diabetes compared with younger and middle-aged groups. However, we still don’t fully understand why their burden is so high. The contribution of age-related declines in muscle mass — commonly termed sarcopenia — to the development of diabetes in older age remains unclear. This is important because skeletal muscle is the major site of insulin-mediated glucose uptake in the body, and sarcopenia may reduce the surface area for glucose transport. Our research is significant because it suggests that age-related muscle loss may represent a currently underrecognized target for interventions to prevent the development of diabetes in older adults.”
Kalyani said future studies which can directly assess the skeletal muscle contractile component may shed further insight on the relationships and sex differences that the researchers observed. – by Regina Schaffer
For more information:
Rita R. Kalyani, MD, MHS, can be reached at the Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Johns Hopkins University School of Medicine 1830 E. Monument St., Suite 333, Baltimore, MD 21287; email: email@example.com.
Disclosures: The authors report no relevant financial disclosures.