When the association between age of regular tobacco use initiation (reported retrospectively as a young adult) and intentional self-injury was assessed, those who had initiated regular tobacco use before age 14 had a higher likelihood for intentional self-injury at young adulthood compared to never users. When adjusted for age, sex, baseline school achievement, depression, impulsivity and alcohol dependence symptoms, as well as for parental education, such ‘early-onset’ tobacco use remained significantly associated with self-injury (AOR 4.57, 95%CI 1.93–10.8, p=.001). However, also those who had started regular tobacco use between the ages of 14 and 22 had an elevated risk compared to never users (AOR 3.24, 95%CI 2.02–5.21, p=1.2e-06). Daily cigarette smoking reported at age 14 was associated with age 22 intentional self-injury. When adjusted for multiple confounders, daily smokers at age 14 had an elevated risk (AOR 4.45, 95%CI 2.04–9.70, p=1.8e-04) compared to never smokers at age 14 (Table 1).
