Effect of Weight Gain on Pulmonary Function after Smoking Cessation in the Lung Health Study

The objective of this study was to determine if the weight gain that accompanies smoking cessation is independently associated with reductions in FEV1 and FVC, using a multicenter randomized intervention trial of smoking cessation in 10 communities in the United States and Canada. Enrollees were currently smoking women and men 35 to 60 yr of age with mild-to-moderate airway obstruction. Participants were randomized to one of three study groups: an intensive smoking cessation program with an inhaled bronchodilator (or a placebo), and usual care. Changes in absolute and percent predicted FEV1 and FVC between baseline and fifth annual follow-up visit were monitored in relation to changes in body weight during the interval. At the baseline examination, percent predicted FEV1 was maximal at 90 to 100% ideal body weight (IBW) and was lower as body weight deviated from this range. The FVC decreased linearly when IBW exceeded 100%. Weight gain was greatest during the first 12 mo after smoking cessation. Weight ga...