Background: Smoking cessation is often followed by weight gain, which may attenuate motivation to sustain a quit attempt.
Objectives: The aim was to identify factors associated with weight gain in smokers who received smoking cessation therapy (SCT) in Japan.
Methods: The weight change in 283 smokers between baseline and 12 months after finishing SCT was observed. Factors associated with marked weight gain of 3.5 kg or more were identified using stepwise logistic regression.
Results: Smoking cessation success was 83% (234/283) at the completion of SCT but decreased to 69% (194/283) 12 months later. Twelve months after the end of SCT, age 50 and over (OR = 0.38, 95% CI [0.19, 0.76]) and varenicline use (OR = 0.30, 95% CI [0.11, 0.78]) were protected against marked weight gain, whereas presence of a comorbidity (OR = 3.33, 95% CI [1.10, 10.00]), high level of nicotine dependence at baseline (OR = 2.07, 95% CI [1.09, 3.92]), and successfully quitting smoking (OR = 4.57, 95% CI [1.94, 10.08]) were associated with marked weight gain.
Discussion: Understanding the factors associated with weight gain after smoking cessation can help in the design of nursing interventions to lessen or prevent weight gain among smokers who try to quit.