Association between smoking and the risk of heavy drinking among young women: a prospective study.

AIM To address the association between smoking habits and the risk of later heavy drinking among young women. METHODS Repeated assessments of alcohol and smoking habits were obtained in 1991-93 and 1999-2000 in a Danish representative cohort in Copenhagen. A total of 6369 non- to moderate-drinking Danish women, aged 20-29 years at baseline, attended a follow-up examination and were included in the study. The risk of becoming a heavy drinker (more than 14 drinks per week) 8 years after enrolment was analyzed by means of logistic regression. RESULTS A total of 177 women became heavy drinkers during follow-up. Daily smoking at baseline was associated with an increased risk of becoming a heavy drinker 8 years later. Relative to nonsmokers, the adjusted odds ratios (OR) for becoming a heavy drinker associated with smoking 1-14, 15-24, or more than 24 cigarettes per day were 1.6 (95% confidence intervals (CI) 1.1-2.4), 1.7 (CI 1.1-2.6), and 2.3 (CI 0.9-5.9), respectively. Age at sexual debut modified the effect of smoking, and women with a debut before the age of 15 years had an adjusted OR of 2.9 (CI 1.1-3.9) compared to never-smokers while there seemed to be no effect among women with a sexual debut after the age of 18. In addition, relative to nondrinkers, all of the moderate (1-5 units per week), medium (6-10 units), and large (10-14 units) alcohol consumption at baseline were associated independently with becoming a heavy drinker 8 years later. CONCLUSIONS This study suggests that smoking is an important predictor of later heavy drinking among young women and that this relatively elevated risk is most pronounced among women with an early sexual debut.