Limb Fat to Trunk Fat Ratio in Elderly Persons is a Strong Determinant of Insulin Resistance and Adiponectin Levels

Background: Similar to lipodystrophy syndromes, aging results in increased visceral adiposity with loss of subcutaneous adipose tissue in the extremities. The hypothesis of this study is that the distribution of limb fat to trunk fat (LF/TF) ratio in elderly persons has a stronger correlation than trunk fat alone to insulin resistance and adiponectin levels.

Methods: Thirty-eight elderly participants were divided into an insulin-resistant (IR) group and an insulin-sensitive (IS) group. Limb fat and trunk fat were measured by dual-energy x-ray absorptiometry. Insulin resistance was measured by a hyperinsulinemic-euglycemic clamp.

Results: There was no significant difference between the IS and IR groups with respect to body mass index, body fat index, absolute amount of trunk fat, or percent body fat. However, the difference in LF/TF ratio between the IS (1.02 +/- 0.05) and the IR groups (0.77 +/- 0.05) was highly significantly different (p <.001). Insulin resistance had a stronger correlation to the LF/TF ratio (r = 0.61, p <.001) than to absolute trunk fat (r = -0.32, p =.051). Adiponectin levels had a strong association with the LF/TF ratio (r = 0.63, p <.001), but did not correlate to absolute trunk fat (r = -0.24, p =.18).

Conclusions: The distribution of body fat (LF/TF ratio) in elderly persons is a stronger determinant of insulin resistance and adiponectin levels than is trunk fat alone. The LF/TF ratio can be a useful tool to assess insulin sensitivity in the elderly population.