Skeletal muscle and organ masses differ in overweight adults with type 2 diabetes

Abstract

Whether lean body mass (LBM) composition, especially skeletal muscle and abdominal organs, differs in adults with type 2 diabetes (T2DM) compared with nondiabetic healthy controls has not been investigated. A subset of African-American and Caucasian participants with T2DM from the Look AHEAD (Action for Health in Diabetes) trial had body composition assessed and compared with a sample of healthy controls. Skeletal muscle mass (SMM), liver, kidneys, and spleen mass were quantified using a contiguous slice magnetic resonance imaging (MRI) protocol. Cardiac mass was quantified by either a cardiac gated MRI protocol or by echocardiography. MRI volumes were converted to mass using assumed densities. Dual-energy X-ray absorptiometry assessed LBM. Using general linear models adjusted for height, weight, sex, age, race, and interactions of diabetes status with race or sex, persons with T2DM (n = 95) had less LBM (49.7 vs. 51.6 kg) and SMM (24.1 vs. 25.4 kg) and larger kidneys (0.40 vs. 0.36 kg) than controls (n = 76) (all P < 0.01). Caucasians with T2DM had larger livers (1.90 vs. 1.60 kg, P < 0.0001) and spleens (0.29 vs. 0.22 kg, P < 0.01), and T2DM men had less cardiac mass than controls (0.25 vs. 0.30 kg, P < 0.001). In this sample, T2DM is characterized by less relative skeletal muscle and cardiac mass in conjunction with larger kidneys, liver, and spleen. Further investigation is needed to establish the causes and metabolic consequences of these race- and sex-specific organ mass differences in T2DM.

Keywords: African American; Caucasian; kidneys; liver; magnetic resonance imaging; spleen.

Fig. 1.

Lean body mass by dual-energy X-ray absorptiometry (A), skeletal muscle mass by magnetic resonance imaging (MRI) (B), and kidney mass by MRI (C) in subjects with or without diabetes. T2DM, type 2 diabetes mellitus. Means are adjusted for height, weight, age, sex, and race. *Significantly less than controls (P < 0.05). †Significantly greater than controls (P < 0.05).

Fig. 2.

Liver mass (A) and spleen mass (B) by MRI in subjects with or without diabetes. Means are presented within each race group and are adjusted for height, weight, age, and sex. †Significantly greater than same-race controls (P < 0.0001).

Fig. 3.

Cardiac mass by MRI in subjects with or without diabetes. Means are presented within each sex group and are adjusted for height, weight, age, and race. *Significantly less than male controls (P = 0.005).