Worker exit and suicide and overdose mortality in a cohort of male non-metal mine workers.

Background: Suicides, overdoses, and drug-related liver diseases (deaths of despair) are greatly elevated in the mining and extraction industries compared to other industries. To better understand the drivers of these deaths, we examined suicide or overdose mortality in relation to age at worker exit among a retrospective cohort of 11,009 male mine workers from the Diesel Exhaust in Miners Study II. Methods: We calculated age-adjusted mortality rates (1947-2015) and estimated hazard ratios (HRs) and 95% Confidence Intervals (CI) for suicide or overdose death in relation to age at worker exit (leaving work). The mining industry curtailed its workforce in the early 1980s due to economic downturn; therefore, separate models were fit for worker exit pre- and post-1980. Results: Suicide deaths peaked between 1980 and 1989 at 67.2 per 100,000, more than double the rate in the general population. The hazard rate for suicide or overdose was 2.56 times higher for inactive versus actively employed workers (95% CI: 1.88, 3.50). Based on 187 suicides or overdoses, associations between younger age at worker exit and suicide or overdose death were null or protective before 1980. However post-1980, those who exited between ages 30-39 years had an elevated risk of death HR = 1.33, 95% CI (0.70, 2.53) and those who exited before age 30 had a HR for suicide or overdose of 1.57 (0.83, 2.96) compared to those who exited work after age 55. Conclusion: Worker exit may contribute to the elevated mortality from suicide or overdose among male mine workers, particularly among younger age groups.