A longitudinal study of the influence of smoking on the onset of obesity at a telecommunications company in Japan

Objective. To clarify the influence of smoking on the onset of obesity. Methods. A 5-year follow-up study was carried out on 25,312 workers at the time of their annual health check-up from 1992 to 1997. Pooled logistic regression analyses by sex were performed with age, working conditions and lifestyle as independent variables and the onset of obesity (BMI ≥ 26.4) as a dependent variable adjusted for the time period. Results. In males, the following factors increased the risk of the onset of obesity: smoking equal to or more than 20 cigarettes per day (versus nonsmokers), monthly holidays fewer than 5 days (versus > 7 days), one-way commute more than 90 min (versus ≤ 60 min), sleeping less than 5 h, moderate and high preference for fatty meals (versus little preference). In females, 30–39 years, 40–49 years and 50–59 years (versus 20–29 years), being an ex-smoker, smoking fewer than 20 cigarettes per day, smoking equal to or more than 20 cigarettes per day (versus nonsmokers, respectively) and high preference for fatty meals (versus little preference) increased the risk of the onset of obesity. Conclusion. This study revealed that smoking independently increases the risk of the onset of obesity regardless of sex.