In the current study, we set out to analyze the possible association with the OPRM1 A118G (Asn40Asp) polymorphism and both alcohol use disorders and alcohol consumption in three separate large general population-based cohorts of Finnish origin. The association between OPRM1 polymorphism and alcohol use disorders was investigated in a study population comprising of 503 individuals with the DSM-IV diagnosis of alcohol dependence or alcohol abuse and their 506 age- and sex-matched controls. Our study population was drawn from a nationwide Health 2000 study cohort consisting of altogether 8028 individuals representative of the Finnish population. The Finnish population provides an excellent basis for genetic analyzes as it has remained genetically very homogeneous when compared with the majority of other populations of Caucasian origin. The other two general population-based cohort studies, FINRISK (n = 2360) and the Helsinki Birth Cohort Study (HBCS, n = 1393), lacked diagnosis-based information, but included detailed information on alcohol consumption. Molecular epidemiological studies on the association between OPRM1 polymorphism and alcohol consumption, based on this kind of data, have not been published before.
