Suicide and self-harm trends in recent immigrant youth in Ontario, 1996-2012: a population-based longitudinal cohort study

Objective To describe the trends in suicide and emergency department (ED) visits for self-harm in youth by immigration status and immigrant characteristics. Design Population-based longitudinal cohort study from 1996 to 2012 using linked health and administrative datasets. Setting Ontario, Canada. Participants Youth 10 to 24 years, living in Ontario, Canada. Exposure The main exposure was immigrant status (recent immigrant (RI) versus long-term residents (LTR)). Secondary exposures included region of birth, duration or residence, and refugee status. Main outcome measure Trends over time in suicide and ED self-harm were modelled within consecutive 3-year time periods. Rate ratios were estimated using Poisson regression models. Results 2.5 to 2.9 million individuals were included per cohort period. LTR suicide rates ranged from 7.4 to 9.4/100 000 male person-years versus 2.2-3.4/100 000 females. RI's suicide rates were 2.7-7.2/100,000 male versus 1.9-2.7/100 000 female person-years. Suicide rates were lower among RI compared with LTR (adjusted relative rate (aRR)=0.70, 95% CI=0.57 to 0.85) with different mechanisms of suicide. No significant time trend in suicide rates was observed (p=0.40). ED self-harm rates for LTR and RI were highest in females (2.6-3.4/1000 LTR females versus 1.1-1.5/1000 males, 1.2-1.8/1000 RI females versus 0.4-0.6/1000 males). RI had lower rates of self-harm compared with LTR (aRR=0.60, 95% CI=0.56 to 0.65). Stratum-specific rates showed a steeper decline per period in RI compared with LTR (RI: aRR=0.85, 95% CI=0.81 to 0.89; LTR: aRR=0.91, 95% CI=0.90 to 0.93). Observed trends were not universal across region of origin and by refugee status. Interpretation Suicide rates have been stable and ED self-harm rates are declining over time among RI youth. These trends by important subgroups should continue to be monitored to allow for early identification of subpopulations of immigrant youth in need of targeted and culturally appropriate public health interventions.