Association between muscle mass and diabetes prevalence independent of body fat distribution in adults under 50 years old

BACKGROUND/OBJECTIVES: Although relatively less muscle mass has been associated with greater diabetes prevalence, whether there is an association between muscle mass and diabetes prevalence independent of body fat distribution is unknown. The objective was to determine whether less skeletal muscle mass is associated with greater diabetes prevalence in young men and women independent of body fat distribution. SUBJECTS/METHODS: One thousand seven hundred and sixty-four adults, aged 20–49 years old, from the United States National Health and Nutrition Examination Survey (2005–2006). Body composition, including appendicular lean mass (ALM), was measured by dual-energy x-ray absorptiometry. Diabetes was defined as fasting blood glucose ≥7 mmol/l, 2-h blood glucose ≥11.1 mmol/l on 75 g OGTT, HbA1c ≥ 48 mmol/mol (6.5%), use of diabetes medications, or self-reported diagnosis of diabetes. RESULTS: The odds of diabetes were 1.31 times higher in men [OR 1.31 (1.18–1.45), p = 0.0001], and 1.24 times higher in women [OR 1.24 (1.05–1.46), p = 0.01], per percent decrease in ALM/weight after controlling for age, race, height, smoking, and education. After additionally controlling for android/gynoid fat, the odds of diabetes were 1.20 times higher per percent decrease in ALM/weight in men [OR 1.20 (1.04–1.37), p = 0.01]; an inverse association was also observed in women, albeit was not statistically significant [OR 1.08 (0.90–1.30), p = 0.42]. CONCLUSIONS: Less muscle mass was associated with greater diabetes prevalence independent of body fat distribution in young men. The association was not statistically significant in women after controlling for android and gynoid adiposity. Low muscle mass could be a causal factor in the development of type 2 diabetes or a correlated marker of higher metabolic risk.