Femoral–gluteal adiposity is not associated with insulin sensitivity in Type 1 diabetes

Aims  To quantify and compare associations between femoral–gluteal adiposity and insulin sensitivity in adults with Type 1 diabetes mellitus with adults with normal glucose tolerance. Methods  Individuals with Type 1 diabetes ( n  = 28) were recruited from the Pittsburgh Epidemiology of Diabetes Complication study, a 24‐year prospective study of childhood‐onset diabetes, and compared cross‐sectionally with individuals with normal glucose tolerance ( n  = 56) of similar age, sex and BMI. Insulin sensitivity was defined as whole‐body glucose disposal measured by hyperinsulinaemic–euglycaemic clamps. Adiposity was quantified by dual energy X‐ray absorptiometry. Results  Individuals with Type 1 diabetes exhibited lower insulin sensitivity (5.8 vs. 8.2 mg min −1  kg fat‐free mass −1 , P  < 0.01), lower total fat mass (20.1 vs. 29.0 kg, P  < 0.001) and lower proportional leg fat mass (36.0 vs.37.7%, P  = 0.03), but similar proportional trunk fat (% trunk fat mass) compared with individuals with normal glucose tolerance. Overall, results from linear regression demonstrated that higher % leg fat mass ( P  < 0.01) and lower % trunk fat mass ( P  < 0.01) were independently associated with lower insulin sensitivity after adjustments for age, sex, height, total fat mass (kg) and diabetes status. Higher % leg fat mass was independently associated with higher insulin sensitivity in individuals with normal glucose tolerance ( P  < 0.01) after similar adjustment; significant associations were not observed in Type 1 diabetes. Conclusions  Reduced insulin sensitivity is a prominent feature of Type 1 diabetes and is associated with total and abdominal adiposity. Compared with adults with normal glucose tolerance, leg fat mass does not show any positive association with insulin sensitivity in Type 1 diabetes.