Correlations among obesity-associated gene polymorphisms, body composition, and physical activity in patients with type 2 diabetes mellitus

CONTEXT: Various studies have focused on the correlation between β2-adrenergic receptor (β2AR), the β3-adrenergic receptor (β3AR), and the uncoupling protein 1 (UCP1) polymorphisms and obesity in patients with type 2 diabetes mellitus (T2DM). AIMS: We examined the correlation between these polymorphisms and body composition variables and between body composition and lifestyle variables in Japanese T2DM patients. MATERIALS AND METHODS: Of the 48, T2DM outpatients in Kanagawa prefecture recruited for participation, 32 (6 men and 26 women) met the study criteria and were enrolled. Obesity-related gene polymorphisms were identified in 3 genes β3AR, UCP1, and β2AR using the SMart amplification process. Body composition variables were measured using a body composition analyzer. Data regarding food and nutrient consumption, family history, and lifestyle factors were collected via administration of questionnaires. RESULTS: Because significant differences in body composition variables were found between men and women, statistical analysis was performed with data from the 25 female subjects only. On the basis of results of genetic testing, the subjects were divided into genotype groups for two-group and three-group comparison. The β3AR, UCP1, and β2AR polymorphisms and body composition significantly correlated with the percentage of subcutaneous fat in both arms as compared with the wild type or hetero groups with β3AR polymorphisms. However, physical activity correlated with several body composition variables. CONCLUSIONS: These results suggest that obesity in T2DM patients is not the result of presence of an obesity-related gene polymorphism but rather the absence of daily physical activity.