The association between abdominal muscle and type II diabetes across weight categories in diverse post-menopausal women.

Context: Despite the key role of muscle in glucose regulation, little is known about the association between muscle area and prevalence of metabolic disorders, or the role low muscle may play in normal weight metabolic obesity.

Objective: The objective was to assess the independent associations between both abdominal muscle and fat depositions (measured by computed tomography) and the prevalence of type II diabetes, and to explore the modifying role of weight category.

Design: We conducted a cross-sectional analysis of the 2001-2002 visit for the Rancho Bernardo Study, Filipino Women's Health Study, and Health Assessment Study of African American Women.

Setting And Participants: Participants were 392 community-dwelling older women (mean age = 64) free of clinical cardiovascular disease.

Main Outcome Measure: The main outcome was prevalence of type II diabetes, defined as use of anti-diabetes medication, fasting plasma glucose ≥ 126 mg/dL, and/or OGTT ≥ 200 mg/dL.

Results: Adjusting for demographics, hypertension, estrogen use, lipids, smoking, physical activity, visceral fat area, and height, a greater muscle-to-total abdominal area ratio (MAR) was associated with lower odds of diabetes [OR = 0.63 per standard deviation, 95% CI (0.43-0.92), p = .02]. Higher visceral fat was associated with greater odds of diabetes in fully adjusted models including total muscle area [OR = 1.48, 95% CI (1.09, 2.01), p = .01]. Associations between MAR and diabetes were stronger for normal weight (BMI 18.5-24.9; OR = 0.32) than overweight/obese women (BMI ≥ 25, OR = 0.71, p-for-interaction = 0.046). Associations with visceral fat did not differ by BMI (p-for-interaction = 0.71).

Conclusions: In older women, abdominal muscle area is inversely associated with type II diabetes independent of visceral adiposity, particularly for normal weight women.