In this issue of ThoraxPelkonen et al 1 make another contribution to the substantial body of literature relating smoking habit, lung function, and long term mortality. In this paper the effects of smoking cessation are emphasised, describing 30 years of follow up of a Finnish cohort recruited in 1959 for the Seven Countries study of coronary artery disease. It is somewhat unusual in that the study enrolled essentially all the age eligible (40–59 years) men in two localities and had extremely high rates of follow up. Lung function was measured at baseline, as were other risk factors for coronary disease such as smoking habit, blood pressure, cholesterol, and body mass index. About half of the 1600 men were smoking on entry to the study and about 37% of them quit during follow up. Baseline lung function was reasonable, with two thirds of the men having forced expiratory volume in one second in 0.75 of a second (FEV_0.75) of more than 88% of predicted normal. One third, the lowest tertile, had values below this, and presumably some were in the range of clinical obstructive disease.

Lung function predicted overall mortality after adjustment for coronary risk factors; men in the lowest tertile of lung function were significantly more likely to die than the rest, and men in the middle tertile with expiratory flows of …