Association of codon 16 and codon 27 β2-adrenergic receptor gene polymorphisms with obesity:: A meta-analysis

Objective: To search for an association between the Glu27Gln (rs1042714; B27) and the Arg16Gly (rs1042713; B16) polymorphisms of the beta 2-adrenergic receptor (ADRB2) gene and obesity. Methods: Meta-analysis of published studies, included if subjects were genotyped at either codon 27 (B27) or codon 16 (B16) of the ADRB2 gene and both obese and nonobese subjects were selected, based on a reported cutoff BMI limit. Initial selection included 14,444 subjects genotyped at B27 (rs1042714) and 6,825 genotyped at B16 (rs1042713). After testing each control group for Hardy-Weinberg equilibrium, the final selection included 10,404 subjects and 4,328 subjects, respectively. Studies were published before 18 August 2006. Results: The frequency of Glu27 allele carriers, either homozygous or heterozygous, ranged from 6.71% in Aymara American Indians to 78.29% in a Dutch population. The frequency of Arg16 allele carriers varied from 51.4 to 64.6% in Europeans and from 71.1 to 85.6% in East Asians. The summary odds ratio (OR) from overall analyses showed no association between either rs1042714 or rs1042713 and obesity. In race groups with low Glu27 allele frequency (Asians, Pacific Islanders, and American Indians), ORs revealed a significant obesity risk associated with rs1042714. These results were not found in East Asians for rs1042713. Discussion: The presence of the Glu27 allele in the ADRB2 gene appears to be a significant risk factor for obesity in Asians, Pacific Islanders, and American Indians, but not in Europeans. Obesity does not appear to be associated with the Arg16 allele.