Risk factors for completed suicide in the general population: A prospective cohort study of 242, 952 people

Background: The estimated global burden of suicide is almost 1 million deaths per year, representing 57% of all violent deaths worldwide. In order to better identify at risk individuals and develop effective prevention strategies at the population level, a comprehensive understanding of the biological, psychological and social risk factors is required. Method: Data from the National Health Interview Survey (1997- 2004) were analyzed. Multivariable Cox proportional hazards regression models were used to compute hazard ratios (HRs) and accompanying 95% confidence intervals (CI). Results: During a mean 6.3 years of follow-up of 242, 952 people (1.56 million person-years), 180 deaths due to suicide occurred. Of 18 risk factors, eight revealed associations with suicide. Participants who had never been married (HR, 2.58; 95% CI, 1.44-4.62), current smokers (HR, 2.26; 1.49-3.43), current drinkers (HR, 1.93; 1.14-3.27]), participants with serious psychological distress (HR, 3.34; 1.81-6.18), and a history of emphysema (HR, 2.79; 1.18-6.59), liver disease (HR, 4.63; 2.10-10.20), kidney disease (HR, 2.26; 1.00-5.06) and cancer (HR, 2.18; 1.32-3.59) were at increased risk of completed suicide. Limitations: Due to the observational nature of this study, we cannot exclude the possibility of reverse or bi-directional causality. Conclusions: This large, prospective cohort study identified a series of biopsychosocial risk factors that may have utility in suicide prevention.