Quit smoking and control weight for greatest benefit

Smokers who quit show big improvements in breathing ability, especially if they do not gain weight, says new research.

The study looked at the benefits to the lungs of giving up smoking, and the factors that affect these benefits. Lung function naturally reduces with age, but is accelerated by smoking.

Professor Susan Chinn of King’s College London, UK, and colleagues asked 6,600 people in 27 countries about their smoking history and weight, and compared this to two lung tests taken eight years apart.

As expected, lung function declined faster in smokers than non-smokers and quitters. Recent quitters gained the most weight, and increasing weight accelerated decline in lung function, especially for men. Putting on weight reduced the benefit of quitting by 38 per cent in men and 17 per cent in women.

Professor Chinn says: "Our data suggest that quitting smoking is beneficial for lung health, but weight gain is an important factor in reducing the beneficial effects of quitting on lung function in men, and that interventions to reduce this weight gain might be warranted."

Results appear in this week’s issue of the Lancet, with a commentary by Professor Graham Colditz of Harvard Medical School, Boston, USA.

He writes: "Chinn and colleagues’ findings are important. The survey shows that slowing of lung decline is an added benefit of quitting. The findings highlight the potential for even greater health benefit if weight gain could be prevented after smoking cessation."

Lancet 2005; 365: 1629-35, 1600-01