Smoking accelerates the natural age-related decline in lung function. A graph adapted from Fletcher and Peto shows lung function decreasing more sharply with age in smokers compared to non-smokers. Quitting smoking at any age can slow down or stop further smoking-related loss of lung function.

1. Copyright ©2008 BMJ Publishing Group Ltd. Parkes, G. et al. BMJ 2008;336:598-600 Fig 1 Graph of lung function against age showing how smoking accelerates age related decline in lung function (adapted from Fletcher and Peto11)