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.