title: Risk of schizophrenia and minority status: a comparison of the Swedish-speaking minority and the Finnish-speaking majority in Finland.
abstract: Approximately five percent of the Finnish population are Swedish-speaking and have higher socioeconomic position and longer life expectancy than the Finnish-speaking majority. Previous studies have not investigated whether Swedish-speaking Finns have lower risk of schizophrenia spectrum disorders (SSD) than Finnish-speaking Finns. We investigated this in a representative sample of 47 445 Finns born in 1972-1984. Hazard ratios of SSD between language groups were assessed with conditional proportional hazards regression. Sex, parental ages at birth, paternal employment around conception, parental psychosis and place and residence in the capital area were used as other explanatory variables. The prevalence of SSD was 0.7% in the Swedish-speaking minority and 1.5% in the Finnish-speaking majority. In the adjusted regression model, belonging to the Swedish-speaking minority was associated with lower risk of SSD (hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.24-0.69). In a subset analysis by gender, the protective effect was evident among Swedish-speaking males (HR 0.32, 95% CI 0.15-0.68) but marginal in females (HR 0.75, 95% CI 0.41-1.37). Parental psychosis and place of birth in the capital area were associated with higher risk of SSD, whereas paternal employment at the time of conception was associated with lower risk of SSD. Our results support the role of social factors in the etiology of schizophrenia. Belonging to a minority with high socioeconomic status and social capital may be protective against schizophrenia, especially for males.
authors.affiliation: Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, P.O.BOX 30, FI-00271 Helsinki, Finland; Tampere School of Public Health, University of Tampere, FI-33014 Tampere, Finland. Electronic address: jaana.suvisaari@thl.fi.
authors.forename: Jaana
authors.initials: J
authors.lastname: Suvisaari
authors.affiliation: NYU School of Medicine, Department of Psychiatry,1 Park Avenue, New York, NY 10016, USA. Electronic address: mark.opler@prophase.com.
authors.forename: Mark
authors.initials: M
authors.lastname: Opler
authors.affiliation: Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Topeliuksenkatu 41 aA, FI-00250 Helsinki, Finland. Electronic address: marja-liisa.lindbohm@ttl.fi.
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Lindbohm
authors.affiliation: Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Topeliuksenkatu 41 aA, FI-00250 Helsinki, Finland. Electronic address: markku.sallmen@ttl.fi.
authors.forename: Markku
authors.initials: M
authors.lastname: Sallmén
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D018672:Community Health Planning; D005260:Female; D005387:Finland / Q000453:epidemiology / Q000208:ethnology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008913:Minority Groups / Q000706:statistics & numerical data*; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology* / Q000208:ethnology*; D013548:Sweden / Q000208:ethnology; D055815:Young Adult
keywords: Minority status; Schizophrenia spectrum disorders; Social risk factors; Urban birth