Heterogeneous glycaemic and insulinaemic responses to oral glucose in non-diabetic men: interactions between duration of obesity,body fat distribution and family history of diabetes mellitus

Summary The interaction between environmental and genetic factors in the alterations of glucose-insulin homeostasis was studied in 104 non-diabetic men. Family history of diabetes mellitus was used as an index of genetic predisposition to diabetes. Body composition was measured by under-water weighing whereas subcutaneous and visceral adipose tissue areas were measured at the abdominal and femoral levels by computed tomography. The sample was first divided into two groups. The first group included subjects with normal glycaemic and insulinaemic responses during a 75 g oral glucose tolerance test. The second group was composed of subjects either with a high glucose response or high insulin response or both. Men included in the second group were different from the normal subjects for almost all body fatness variables. They also presented a prevalence of a positive family history of diabetes which was significantly higher than normal subjects. The second group was then divided into three distinct subgroups based on insulin and glucose responses of the subjects during the oral glucose tolerance test. Subjects with high insulin but normal glucose responses were characterized by significantly higher levels of total body fat and deep abdominal adipose tissue when compared to the normal group (p<0.05). Men with both high insulinaemic and glycaemic responses displayed higher body fatness values and higher deep and subcutaneous abdominal adipose tissue areas (p<0.05) in comparison with normal subjects. They also had a higher body mass index at age 20 years than control subjects and subjects with high insulin but normal glucose responses. In contrast, subjects with normal insulin but with high glucose responses were not different from the normal group with regard to body fat and adipose tissue areas. These results show the heterogeneous origin of altered glucose-insulin homeostasis in non-diabetic men. Finally, subjects in the altered glucose-insulin homeostasis group with no family history of diabetes displayed a higher body mass index at age 20 years (p<0.05) in comparison with subjects who had a positive family history of the disease. They also presented a greater abdominal-to-thigh fat ratio measured by computed tomography. These results suggest that in men with alterations of glucose-insulin homeostasis, the relationship of body fat distribution to glucose tolerance and plasma insulin levels is different in those with no family history of diabetes than in subjects with a positive family history of diabetes.