Insulin and extremity lean mass in overweight or obese Women

Wednesday, October 10, 2012 — Poster Session II
Noon – 2:00 p.m	Natcher Conference Center, Building 45	NHLBI	CLIN/TRANS-16

Authors

• B.M. Leon
• S. Jenkins
• K. Pepin
• H. Chaudry
• K.P. Smith
• G.G. Zalos
• M.A. Waclawiw
• B.V. Miller
• A.E. Sumner
• K.Y. Chen
• R.O. Cannon

Abstract

Obesity is associated with increases in fat and lean mass. Increased leg lean mass may be compensatory to adiposity, but the relation of arm lean mass to obesity is unclear. We propose that elevated insulin levels may contribute to extremity lean mass in overweight/obese women. The following measurements were performed in 194 women: dual-energy X-ray absorptiometry for fat and lean masses; peak oxygen consumption (VO2 peak) during graded treadmill exercise; fasting insulin and, insulin-sensitivity (SI) calculated from the minimal-model. 123 subjects completed 6 months in a worksite wellness program, with repeat of all measurements above. Baseline SI was negatively, and insulin positively, associated with both leg and arm lean masses (all P< 0.001), independent of age and height. Reduction in fasting insulin following completion of the program was associated with reduction in both leg (P=0.015) and arm (P=0.017) lean masses, independent of reduction in fat mass or improvement in VO2 peak, and without significant improvement in SI. Hyperinsulinemia in overweight/obese women is associated with increased lean mass in weight-bearing and non-weight-bearing extremities, which is partially reversible with reduction in insulin, independent of fat mass loss or improvement in exercise performance and consistent with stimulatory effects of insulin on muscle mass.

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