Body mass decrease after initial gain following smoking cessation

Background Although smoking cessation is strongly associated with subsequent weight gain, it is not clear whether the initial gain in weight after smoking cessation remains over time. Method Cross-sectional analyses were made, using data from periodic health examinations for workers, on the relationship between body mass index (BMI) and the length of smoking cessation. In addition, linear regression coefficients of BMI on the length of cessation were estimated according to alcohol intake and sport activity, to examine the modifying effect of these factors on the weight of former smokers. Results Means of BMI were 23.1 kg/m(2), 23.3 kg/m(2), 23.6 kg/m(2) for light/medium smokers, heavy smokers and never smokers, respectively. Among former smokers who had smoked greater than or equal to 25 cigarettes a day, odds ratio (OR) of BMI >25 kg/m(2) were 1.88 (95% confidence interval [CI] : 1.05-3.35), 1.32 (95% CI:0.74-2.34), 0.66 (95% CI:0.33-1.31) for those with 2-4 years, 5-7 years, and 8-10 years of smoking cessation, respectively. The corresponding OR among those who previously consumed <25 cigarettes a day were 1.06 (95% CI:0.58-1.94), 1.00 (95% CI:0.58-1.71), and 1.49 (95% CI:0.95-2.32). Conclusions The results suggest that although heavy smokers may experience large weight gain and weigh more than never smokers in the few years after smoking cessation, they thereafter lose weight to the never smoker level, while light and moderate smokers gain weight up to the never smoker level without any excess after smoking cessation.