The OPRM1 A118G (Asn40Asp, rs1799971) polymorphism was successfully genotyped in altogether 4762 samples (n = 1009 in Health 2000, n = 1393 in HBCS and n = 2360 in FINRISK). The background characteristics and OPRM1 polymorphism genotypes of the Health 2000, FINRISK and HBCS population samples are shown in Table 1. Table 1.Demographic characteristics and OPRM1 A118G genotype and allele frequencies in the three Finnish cohortsHealth 2000FINRISKHBCSn (%)/mean (SD)n (%)/mean (SD)n (%)/mean (SD)n100923601393aMen812 (80.5%)1078 (45.7%)554 (39.8%)Age (years)46.4 (11.3)50.6 (14.0)63.4 (2.9)A118G MAF(G)20.8%18.6%19.0% A/A645 (63.9%)1555 (65.9%)916 (65.7%) A/G309 (30.6%)734 (31.1%)425 (30.5%) G/G55 (5.5%)71 (3.0%)52 (3.7%)MAF, minor allele frequency; SD, standard deviation.aDistribution of genotypes before applying quality control filters.
