Family history of type 2 diabetes, abdominal adipocyte size and markers of the metabolic syndrome

BACKGROUND/OBJECTIVES: A major risk factor of type 2 diabetes mellitus (T2DM) is a positive family history of diabetes. First degree relatives (FDR) of patients with T2DM are more insulin resistant and are reported to have larger abdominal subcutaneous adipocytes than adults without a family history. Our objectives were to assess whether FDR of T2DM are associated with larger abdominal adipocytes independent of age, sex and abdominal subcutaneous fat and to assess whether a family history of T2DM is also independently related to femoral adipocyte size, as well as visceral fat and fasting plasma triglyceride (TG) concentrations. METHODS: We extracted adipocyte size, body composition, plasma TG and demographic data of non-diabetic research participants of previous studies conducted in our laboratory. We ascertained the family history of T2DM from the electronic medical records. Multivariate regression analysis was used to assess whether FDR of T2DM are more likely to have other risk factors after adjusting for known covariates. RESULTS: Of 604 participants, 148 were FDR of T2DM. Although abdominal and femoral adipocyte size was greater in FDR of T2DM than those without a family history (0.74 +/- 0.33 vs 0.63 +/- 0.33 mu g lipid per cell, P < 0.001; 0.81 +/- 0.29 vs 0.72 +/- 0.33 mu g lipid per cell, P = 0.01, respectively), this was confounded by FDR of T2DM being older, having greater body mass index and percent body fat. A family history of T2DM was a significant predictor of abdominal adipocyte size after adjustment for age and body fat distribution parameters in females (total R-2 = 0.5, P < 0.0001), but not in males. A family history of T2DM was not independently predictive of femoral adipocyte size, visceral fat area or TG. CONCLUSIONS: Female FDR of T2DM have larger abdominal, but not femoral, adipocytes, even after accounting for age and body fat distribution.