Smoking and Lung Function1–4

In a cross-sectional survey of 3 separate communities, we studied the white residents 7 yr of age and older in order to determine the relation between cigarette smoking and lung function. We identified 2,817 nonsmokers, 664 ex-smokers, and 1,209 smokers who were further classified as light smokers (1 to 20 cigarettes per day) and heavy smokers (> 20 cigarettes per day). Residual lung function (observed-predicted) was examined in these groups for forced expiratory volume in one second (rFEV1) and for maximal expiratory flow rates at 50% and 25% of the vital capacity (rmax50% and rmax25%). Mean residuals by sex, age, and smoking category were compared and revealed an increasing progression of lung function loss with advancing age in males and females in all smoking categories. These age-related trends were due primarily to the amount smoked by persons in each group. The age of onset of these abnormalities was found to be as early as the age group 15 to 24 yr. Abnormalities were greater in smokers than ex-sm...