Religion and assisted and non-assisted suicide in Switzerland: National Cohort Study

Background In the 19th century, eminent French sociologist Emile Durkheim found suicide rates to be higher in the Protestant compared with the Catholic cantons of Switzerland. We examined religious affiliation and suicide in modern Switzerland, where assisted suicide is legal. Methods The 2000 census records of 1 722 456 (46.0%) Catholics, 1 565 452 (41.8%) Protestants and 454 397 (12.2%) individuals with no affiliation were linked to mortality records up to December 2005. The association between religious affiliation and suicide, with the Protestant faith serving as the reference category, was examined in Cox regression models. Hazard ratios (HRs) with 95% confidence intervals (CIs) were adjusted for age, marital status, education, type of household, language and degree of urbanization. Results Suicide rates per 100 000 inhabitants were 19.7 in Catholics (1664 suicides), 28.5 in Protestants (2158 suicides) and 39.0 in those with no affiliation (882 suicides). Associations with religion were modified by age and gender (P < 0.0001). Compared with Protestant men aged 35–64 years, HRs (95% CI) for all suicides were 0.80 (0.73–0.88) in Catholic men and 1.09 (0.98–1.22) in men with no affiliation; and 0.60 (0.53–0.67) and 1.96 (1.69–2.27), respectively, in men aged 65–94 years. Corresponding HRs in women aged 35–64 years were 0.90 (0.80–1.03) and 1.46 (1.25–1.72); and 0.67 (0.59–0.77) and 2.63 (2.22–3.12) in women aged 65–94 years. The association was strongest for suicides by poisoning in the 65–94-year-old age group, the majority of which was assisted: HRs were 0.45 (0.35–0.59) for Catholic men and 3.01 (2.37–3.82) for men with no affiliation; 0.44 (0.36–0.55) for Catholic women and 3.14 (2.51–3.94) for women with no affiliation. Conclusions In Switzerland, the protective effect of a religious affiliation appears to be stronger in Catholics than in Protestants, stronger in older than in younger people, stronger in women than in men, and particularly strong for assisted suicides.