Those who reported being active smokers in 1975 had a higher risk of suicide from 1976 to 2011 than those who reported never smoking [hazard ratio (HR), 2.59, 95% CI 1.87–3.62], with little variation by sex or age (Table 2). The proportionality assumption was not violated (time × smoking interaction p = 0.35, time × sex interaction p = 0.46). In addition, risk for suicide was elevated in those who were baseline (1975) smokers but with follow-up initiated from 1 January 1986 with follow-up to 2011 (1986–2011, 160 suicides, HR 2.89, 1.94–4.31). Correspondingly, an analysis in cohort members alive as of 1 January 1996 with follow-up until the end of 2011 showed an association with smoking at baseline (1975) (1996–2011, 72 suicides, HR 2.73, 1.52–4.88). Heavy smokers in 1975 had higher suicide risk over 35 years of follow-up (HR 3.47, 95% CI 2.31–5.22) than daily smokers who smoked less (HR 2.3, 95% CI 1.61–3.23) (p = 0.017, test of homogeneity of regression coefficients), with never smokers as overall reference (HR 1). Age of smoking initiation among active smokers, i.e. initiation
