Time trend of suicide in Swiss male farmers and comparison with other men: a cohort study.

The ongoing agricultural reforms present serious challenges for Swiss farmers. Pressure is growing with difficult economic situations and the increasing demands for environmental protection, animal welfare and food safety. The aim of this study was to determine whether the strain is associated with higher risk of suicide in farmers than in men in other professions. We also wanted to analyse any changes in trends over time. Using the Swiss National Cohort, a population-based longitudinal study (1991–2014), we investigated suicide rates for Swiss men aged 35 to 74 years who lived in small communities. We calculated crude rates of suicide and standardised mortality ratios (SMRs) for both calendar periods of four years, and overall. We estimated hazard ratios using Cox proportional hazard regression models of increasing complexity to examine associations with profession (farmer, non-farmer), calendar period, marital status, type of household, religion and language region. We identified 9006 suicides among 1,796,379 men in the total study population, of which 447 occurred in 89,303 farmers. Age-standardised rates of suicide per 100,000 person-years were higher (38.1, 95% CI 34.6–41.8) in farmers than in men with other professions (32.6, 95% CI 31.9–33.3). Although the age-standardised rates decreased for the whole study population until 2006, the declining trend continued afterwards only in non-farmers. The widening gap between farmers and non-farmers also showed in the SMR, which increased from 1.06 (95% CI 0.88–1.27) in the period 1991–1994 to 1.37 (95% CI 1.05–1.79) in 2011-2014. The Cox regression model analyses also revealed a higher risk of suicide for farmers, with hazard ratios ranging from 1.10 (95% CI 1.00–1.22) to 1.17 (95% CI 1.07–1.29). Usage of firearms was the most common method in the overall population (36.5%). In farmers, however, almost 60% committed suicide by hanging. The study shows a higher rate of suicide in farmers compared to non-farmers in Switzerland, with the gap widening increasingly after 2006. It underlines the importance of identifying the difficulties and concerns of male farmers at an early stage in order to make appropriate structural adjustments and to offer low-threshold assistance tailored to their needs and preferences.