Demographic and clinical data for subjects with each b-AR genotype are presented in Table S1 and S2. The subgroups in three genotypes did not differ in age, gender ratio, smoking status, or body mass index. There was no detectable deviation from Hardy-Weinberg equilibrium in b 1 -AR Ser49Gly genotype (x 2 = 0.169, P = 0.681), b 2 -AR Arg16Gly genotype (x 2 = 0.824, P = 0.364) or b 2 -AR Gln27Glu genotype (x 2 = 2.188, P = 0.139).