Effects of Pack-Years of Smoking on the Maximal Midexpiratory Flow and Forced Expired Volume in One Second/Vital Capacity in Healthy Adult Males

MMFR and FEV 1 /VC of 250 healthy adult male flying personnel were compared with smoking histories. From these data we derived regression equations to demonstrate changes in pulmonary function related to smoking history. From these data it can be predicted that: 1) as smoking increases, MMFR will indicate changes more readily than will FEV 1 /VC; 2) a statistically significant difference exists in the mean MMFR and FEV 1 /VC in apparently healthy smokers compared with nonsmokers; and 3) decreases in pulmonary function resulting from smoking can be expressed by regression equations, although not at this time at a statistically significant level. Although this study does not provide a means of predicting a decrease in MMFR or FEV 1 /VC in relation to increased smoking, it does provide additional data to support the theory that smoking yields lung damage, and it opens a possible new way of looking at smoking-induced lung damage.