Objective The aim of this research was to compare the risk of all-cause mortality and mortality from all cancers combined, lung cancer, respiratory diseases, cardiovascular diseases and diabetes mellitus between normal-weight smokers and overweight or obese ex-smokers.

Methods Data were from 1997 to 2004 National Health Interview Survey (with response rates ranging from 70% to 80%) which were linked to records in the National Death Index. Mortality follow-up was through 31 December 2006. The sample was limited to normal-weight smokers and overweight/obese ex-smokers 25 years of age and older (n=52 819). HR from Cox regression was computed to represent mortality effect.

Results Results showed that in both women and men, normal-weight smokers, relative to overweight or obese ex-smokers, had a higher risk of mortality from all causes combined, all cancers combined, lung cancer, cardiovascular and respiratory diseases. Among women, there was no difference in mortality risk from diabetes mellitus between normal-weight smokers and overweight or obese ex-smokers. Among men, there was some evidence that the risk of mortality was higher in obese ex-smokers than normal-weight smokers.

Conclusions This article concludes that, overall, mortality risk is smaller in overweight or obese ex-smokers than normal-weight smokers. Smoking cessation interventions can tailor messages that highlight the greater reduction in mortality associated with quitting, compared with potential weight gain.