QUANTITATIVE RELATIONSHIPS BETWEEN CIGARETTE-SMOKING AND VENTILATORY FUNCTION

Abstract

In a general population sample, highly significant quantitative relationships were noted between pack-years of smoking and functional impairment. Subjects with chronic productive cough showed steeper declines in the forced expired volume in 1 s and forced expiratory flow after exhalation of 75% of the forced vital capacity .ovrhdot.V max25, but a definite inverse relationship between ventilatory function and pack-years was demonstrated even among subjects who denied any cough or sputum production. Current smoking showed no relationship to 1 s forced expiratory volume or .ovrhdot.V max25 when total pack-years were taken into account. Age appeared to be an important independent determinant of per cent predicted values only in regard to the .ovrhdot.V max25 in symptomatic, nonsmoking women. A history of childhood respiratory trouble was associated with a lower ventilatory function regardless of smoking habits, and for this reason such subjects were deleted from detailed analyses of dose-effect relationships. Allergy skin test reactivity in young to middle-aged adults showed a significant additive effect to pack-years as a determinant of forced expiratory flow toward the end of the forced vital capacity, but the effect was noted only among present smokers.