Role of body fat distribution in the decline in insulin sensitivity and glucose tolerance with age.

Abstract

The relationships of body composition and physical fitness [maximal aerobic capacity (VO2max)] to the decline in insulin sensitivity with age were examined in healthy older (47-73 yr; n = 36) and young (19-36 yr; n = 13) men. In 18 older men with normal glucose tolerance (OGTT), glucose disposal rates (M) during hyperinsulinemic euglycemic clamps correlated negatively with the waist to hip ratio (WHR; r = -0.77; P < .001) and percent body fat (r = -0.46; P < 0.05) and positively with VO2max (r = 0.54; P < 0.05), but not with age. Similar relationships existed in the 36 older men with a spectrum of OGTT responses; however, only WHR was independently related to M (r2 = 0.32; P < 0.01). In the older men with normal OGTT, M (mean +/- SEM, 7.88 +/- 0.43 mg/kg fat-free mass.min) was not different from that in the young men (8.56 +/- 0.47; P = NS). Furthermore, in older and young men with normal OGTT matched for WHR, percent fat, or VO2max, glucose disposal was comparable at sequential 15-min intervals during the clamp and in its relationship to insulin concentrations at the tissue level (multicompartmental analysis). In contrast, despite higher steady state plasma insulin levels during the clamp, M was significantly lower in the older men with a higher WHR, greater percent fat, lower VO2max, or impaired OGTT. Thus, in healthy older men up to the age of 73 yr, insulin sensitivity and glucose tolerance are affected primarily by the regional body fat distribution, not age, obesity, or VO2max.

Metabolic effects of diets differing in glycaemic index depend on age and endogenous glucose-dependent insulinotrophic polypeptide in mice

“…Age-associated accumulation of visceral fat is strongly associated with metabolic disturbances including insulin resistance in humans [23,39,40]. In order to recommend the most suitable and effective diets to our patients, it appears to be important investigating whether agedependent differences of low vs high-GI diets also exist in humans.…”

Pioglitazone increases non-esterified fatty acid clearance in upper body obesity

“…Matching for relevant variables is preferable to using numerator/denominator approaches to present NEFA flux data because it prevents drawing spurious conclusions [32]; NEFA flux is most strongly predicted by REE [7]. Substrate oxidation was assessed using CO 2 production relative to O 2 consumption rates and urinary nitrogen excretion [33].…”

Contribution of Abdominal Adiposity to Age-Related Differences in Insulin Sensitivity and Plasma Lipids in Healthy Nonobese Women

“…However, relatively few studies have addressed the potential impact of age-related changes in visceral fat on physiological variables that predict disease outcome, such as plasma lipids and insulin sensitivity (22,23). These studies have generally favored a significant association between visceral fat with alterations in the blood-lipid profile and measures of insulin sensitivity, although this hypothesis remains controversial (17).…”