Longitudinal Smoking Habits As Risk Factors for Early-Onset and Repetitive Suicide Attempts: The Northern Finland 1966 Birth Cohort Study

Purpose We sought to investigate the relationship between regular daily smoking in adolescence and in adulthood, the onset age of suicidal behavior, and the repetitiveness of suicide attempts by the age of 31 years. Methods Data from the Northern Finland 1966 Birth Cohort (NFBC 1966, n = 7995) were linked with the National Finnish Hospital Discharge registers (FHDR). Smoking habits of the cohort members were assessed at the ages of 14 and 31 years. Results After adjusting for hospital-treated psychiatric disorders and several sociodemographic characteristics, women with prolonged smoking from 14 to 31 years especially were at increased hazard (adjusted hazard ratio, 6.67; 95% confidence interval, 3.06–14.52) for having their first suicide attempt at younger age compared with infrequent smokers/nonsmokers. Smoking habits were not associated with the repetitiveness of suicide attempts in either gender. Conclusion This study confirms the association between smoking and suicidality. Further studies are needed to investigate the neurobiological basis of this association.