Smoking cessation, weight gain and risk of cardiovascular disease.

Objective: To examine whether the relationship between smoking cessation and risk of cardiovascular disease (CVD) was modified by weight gain.

Methods: A total of 69 910 participants (29 650 men and 46 260 women) aged 45-74 years were grouped into six groups by smoking status in the first and 5-year surveys: sustained smokers, recent quitters according to postcessation weight gain (no weight gain, 0.1-5.0 kg, >5.0 kg), long-term quitters and never smokers. Quitting smoking within and longer than 5 years were defined as recent and long-term quitters, respectively. We used Cox proportional hazard models to estimate the HR for incident CVD, coronary heart disease (CHD) and stroke.

Results: We identified 4023 CVDs (889 CHDs and 3217 strokes) during a median of 14.8 years of follow-up. Compared with sustained smokers, the multivariable HR (95% CI) for CVD was 0.66 (0.52 to 0.83) for recent quitters without weight gain, 0.71 (0.55 to 0.90) for recent quitters with weight gain of 0.1-5.0 kg, 0.70 (0.44 to 1.10) for recent quitters with weight gain of >5.0 kg, 0.56 (0.49 to 0.64) for long-term quitters, and 0.60 (0.55 to 0.66) for never smokers. The analysis restricted to men showed a similar association. Prespecified analysis by age suggested that recent quitters overall had a lower HR for CVD among those aged <60 years vs ≥60 years. Similar patterns of association were observed in CHD and stroke.

Conclusions: Postcessation weight gain did not attenuate the protective association between smoking cessation and risk of CVD.