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Fat Distribution and Glucose Metabolism in Older, Obese Men and Women

¹ Nutrition, Metabolism, and Exercise Laboratory, University of Arkansas for Medical Sciences, Little Rock. ² Geriatric Research, Education, and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock.

Address correspondence to Robert H. Coker, PhD, Nutrition, Metabolism, and Exercise Laboratory, DWR Institute on Aging, 4301 W. Markham, Slot 806, University of Arkansas for Medical Sciences, Little Rock, AR 72205. E-mail: cokerrobert{at}uams.edu

Background. Previous studies have identified relationships between subcutaneous abdominal fat (SAF), visceral fat (VF), and insulin resistance. In addition, lower muscle attenuation and decreased adiponectin have also been associated with insulin resistance.

Methods. In order to define these relationships within a group of older, obese adults, we studied 48 individuals (20 men; 71 ± 1 years and 28 women; 65 ± 1 years) who underwent a single, hyperinsulinemic, euglycemic clamp procedure, computed tomography scan at the L4-L5 level, and whole-body plethysmography or dual energy x-ray absorptiometry. Endogenous glucose production (basal glucose R_a) was also measured at baseline and during the clamp procedure using an infusion of [6,6²H₂] glucose.

Results. Mean body mass index (BMI; 31 ± 1 kg/m²) and glycosylated hemoglobin A1c (HbA1c; 5.7 ± 0.1%) levels were not significantly different between men and women. In men, there was an inverse relationship between SAF and insulin-stimulated glucose disposal (ISGD) (r = –.60, p =.01). In addition, there was a trend between thigh muscle attenuation and ISGD in men (r =.41, p =.07). Adiponectin was associated with ISGD in men (r =.46, p =.04) and women (r =.48, p =.01). There were no significant relationships between body fat distribution and basal glucose R_a in men or women, and no relationships between triglycerides and glucose metabolism.

Conclusions. Our results indicate that (i) SAF was negatively associated with ISGD in men, (ii) thigh muscle attenuation demonstrated a trend toward ISGD in men, and (iii) adiponectin was associated with ISGD in men and women.