Smoking habits in relation to reproductive events among Japanese women: findings of the Japanese Nurses' Health Study.

OBJECTIVE

The purposes of this study were to examine smoking habits in relation to the reproductive events of pregnancy and menopause and clarify the reasons for smoking cessation among ex-smokers.

METHOD

This is a cross-sectional study based on a baseline survey of a prospective cohort study. From 2001 to 2007, a self-administered questionnaire survey was conducted on 49,927 female nurses from all 47 prefectures in Japan. Logistic regression models were used to estimate age-adjusted odds ratios.

RESULTS

Of the respondents, 17.2% were current smokers, 11.6% were ex-smokers and 69.8% had never smoked. The prevalence of smoking during pregnancy was 7.8%. Among ex-smokers, 30.3% gave "reproductive events" as their reason for smoking cessation. Current smoking and the number of cigarettes smoked per day before menopause were significantly related to onset of menopause.

CONCLUSION

Women's smoking habits have mutual relationships with reproductive events such as pregnancy and menopause. Although "reproductive events" were an important reason for smoking cessation among women, 7.8% of women still smoked during pregnancy. Smoking was correlated with onset of menopause. Support for smoking cessation is an important healthcare issue throughout women's lifetimes.