Analyses of Hardy–Weinberg equilibrium (HWE), genotype and allele frequencies, and association analysis between OPRM1 rs1799971 genotypes and DSM-IV-based alcohol use disorder diagnosis or alcohol consumption were performed using the PLINK program, version 1.07 (http://pngu.mgh.harvard.edu/~purcell/plink/). Additive, dominant and recessive models were analyzed, controlling for age and sex, using linear or logistic regression models. Alcohol consumption was analyzed as a continuous variable. Health 2000 and FINRISK data were log-transformed to attain normality. When analyzing alcohol consumption in Health 2000 study population, the analyses were controlled for the alcohol use disorder diagnosis status.
