Lack of associations between serum leptin, a polymorphism in the gene for the β3-adrenergic receptor and glucose tolerance in the Dutch population.

BACKGROUND The associations between leptin levels and the prevalence of a polymorphism in the beta(3)-adrenergic receptor were studied in a cross-sectional analysis of 600 participants in a population-based study, which were stratified for glucose tolerance by an oral glucose tolerance test. METHODS In a random sample of 600 participants in the Rotterdam study, aged 55-75 years at baseline (309 men, 291 women) the relationships were studied between the presence of Trp64 Arg mutation in the beta(3)-adrenergic receptor gene and fasting leptin, glucose and insulin (fasting and after an oral glucose load), and other components of the insulin resistance syndrome. RESULTS Mean age of the study population was 66.9 years (SD 5.7). Fasting serum leptin levels overall in men and women were 6.1 mu g/l (SE 0.2) and 21.7 mu g/l (0.9), respectively, (P< 0.001). These differences were independent of age, body mass index and waist to hip ratio. We identified 73/600 persons who were heterozygotes for the Trp64 Arg polymorphism (allelic frequency 6.1%), but failed to find an association between the presence of this polymorphism and leptin or any measured parameter indicative for obesity, impaired glucose tolerance or type 2 diabetes mellitus, CONCLUSION Heterozygosity for the Trp64Arg polymorphism of the beta(3)-adrenergic receptor gene is not accompanied by obesity, impaired glucose tolerance and type 2 diabetes mellitus in the general elderly Dutch population, and is also not associated with changes in circulating leptin levels.