Changes in smoking and dietary habits among Japanese female nurses based on the Gunma Nurses' Health Study

Abstract

Objective : The purpose of this study was to examine changes in smoking, drinking, and dietary habits using a questionnaire that was repeated in the same subjects, as well as to determine how the behavioral changes were affected by age and reproductive events.
Subjects and Methods : The Gunma Nurses' Health Study (GNHS) is an ongoing prospective study of a cohort of 699 female nurses. They were followed using a self-reported biennial questionnaire dealing with lifestyle and healthcare practices on women's health, reproductive history, and medical history. The 450 women who responded to all three questionnaires (baseline, second, and third surveys) were included in the analysis. We evaluate the reproducibility of smoking habits and food habits, and examine the impact of these variables on the degree of reproducibility.
Results : The prevalence of current smokers decreased slightly over the 4 years from 14.7% to 11.3%. For smoking habit, the total agreement was 95.0%, and the kappa coefficient was 0.788. Spearman's rank correlation coefficient for food items ranged from 0.545 for milk and dairy products to 0.821 for alcoholic beverages. Age and pregnancy affected the reproducibility of smoking and dietary habits, but menopausal status had no effect on these health habits. Epidemiological studies should consider long-term changes in health habits to assess habitual exposures.