The Trp64Arg polymorphism of the beta(3)-adrenergic receptor gene and obesity in Chinese subjects with components of the metabolic syndrome

BACKGROUND: In regions such as Hong Kong, rapid economic development has le d to lifestyle alterations characterized by increases in energy and fat int ake and reduction in physical activity. These changes have been associated with a dramatic increase in the prevalence of diabetes and related diseases of the metabolic syndrome. OBJECTIVE: To investigate if a common polymorphism (Trp64Arg) of the beta(3 )-adrenergic receptor gene, previously implicated as predisposing to type 2 diabetes mellitus or obesity in other populations, has a role in the appar ent susceptibility of Hong Kong Chinese to diabetes and related disorders. METHOD: A PCR-based protocol was used to genotype 802 Southern Chinese subj ects who were either healthy or had one or more of the metabolic disorders including diabetes, hypertension or dyslipidaemia. RESULTS: The frequencies of the mutant A allele (12.7%) and AA genotype (1. 7%) did not differ, by the chi(2) test, in any patient group with diabetes, hypertension or dyslipidaemia, alone or in combination, compared to health y controls. Using the t-test in the 802 subjects, those carrying the mutant A allele had evidence of increased obesity with a significantly (all P < 0 .05) higher body mass index (BMI, kg/m(2)) and also lower HDL-cholesterol, BMI was also elevated in subjects with the A allele in the separate groups with diabetes, dyslipidaemia or hypertension. Stepwise multiple regression showed this polymorphism to be an independent predictor of BMI. C ONCLUSION: These data do not support any direct involvement of the Trp64Arg polymorphism in the development of diabetes, hypertension or dyslipidaemia in Chinese subjects, but do suggest a relationship with obesity.