Coffee intake, smoking, and pulmonary function in the Atherosclerosis Risk in Communities Study.

Coffee contains polyphenolic antioxidants and caffeine, which may favorably affect pulmonary function. Therefore, the authors studied cross-sectional associations (1987-1989) between coffee intake and pulmonary function in the Atherosclerosis Risk in Communities Study, a population-based cohort study (analytic sample = 10,658). They also conducted analyses stratified by smoking status, since smoking is a strong risk factor for respiratory disease and could influence the effects of caffeine and antioxidants. Self-reported coffee intake was categorized as rare/never, <7 cups/week, 1 cup/day, 2-3 cups/day, and >or=4 cups/day. Pulmonary function was characterized by the spirometric measures forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)). After adjustment for demographic factors, lifestyle characteristics, and dietary factors, pulmonary function values increased across increasing categories of coffee consumption in never and former smokers but not in current smokers. In never or former smokers who consumed >or=4 cups of coffee daily, FVC and FEV(1) were 2%-3% greater than in never or former smokers who rarely/never consumed coffee (P(trend) values: in never smokers, 0.04 for FVC and 0.07 for FEV(1); in former smokers, <0.001 for FVC and <0.001 for FEV(1)). These data show a possible beneficial effect of coffee (or a coffee ingredient) on pulmonary function, but it appears to be limited to nonsmokers.