Suicide in Canadian veterans living in Ontario: a retrospective cohort study linking routinely collected data

OBJECTIVES: To compare the risk of death by suicide in male veterans with age-matched civilians. DESIGN: Retrospective cohort study linking provincial administrative databases between 1990 and 2013 with follow-up complete until death or December 31, 2015. SETTING: Population-based study in Ontario, Canada. PARTICIPANTS: Ex-serving Canadian Armed Forces and Royal Canadian Mounted Police veterans living in Ontario who registered for provincial health insurance were included. A civilian comparator group was matched 4:1 on age and sex. MAIN OUTCOME: Death by suicide was classified using standard cause of death diagnosis codes from a provincial registry of mandatory data collected from death certificates. Fine and Gray sub-distribution hazards regression compared the risk of death by suicide between veterans and civilians. Analyses were adjusted for age, residential region, income, rurality and major physical comorbidities. RESULTS: 20 397 male veterans released to Ontario between 1990 and 2013 and 81 559 age–sex matched civilians were included. 4.2% of veterans died during the study time frame, compared with 6.5% of the civilian cohort. Death by suicide was rare in both cohorts, accounting for 4.6% and 3.6% of veteran and civilian deaths, respectively. After adjustment for confounders, veterans had an 18% lower risk of dying from causes other than suicide (HR 0.82, 95% CI 0.76 to 0.89) and a similar risk of dying by suicide (HR 1.01, 95% CI 0.71 to 1.43), compared with civilians. CONCLUSIONS: Deaths by suicide were rare in male veterans residing in Ontario. Our findings demonstrate that veterans had a similar risk of suicide-related mortality as an age-matched civilian population. A better understanding of effective suicide prevention as well as clarifying pathways to seeking and receiving mental health supports and services are important areas for future consideration.