Controlling a person’s weight after they have given up smoking could help maximise the benefits for their lungs, suggests a study in this week’s issue of The Lancet.
Lung function normally declines with advancing age, and smoking causes premature onset and acceleration of this age-related decline. Stopping smoking is beneficial for lung function but may lead to weight gain. Previous studies have reported the effects of quitting smoking and weight change on lung function, but the total effect has not been reported in a general population study.
Susan Chinn (<<>>, UK) and colleagues sent detailed questionnaires about smoking history to around 6600 people from 27 countries, taking part in the European Community Respiratory Health Survey (ECRHS). Participants had lung function measured in 1991–93, when aged 20–44 years, and in 1998–2002 as part of ECRHS. Smokers had a greater decline in lung function than those who never smoked, and quitters and sustained quitters had a lower rate of decline. During follow-up mean weight and body mass index (BMI) increased in men and women. The increase in weight was greatest in recent quitters and smallest in people who quit and restarted. The effect of increasing weight or BMI on decline in lung function was substantially greater in men than in women, diminishing the benefit of quitting by 38% in men, and 17% in women.