Modulation of the acute respiratory effects of winter air pollution by serum and dietary antioxidants: a panel study

This study investigated whether a high dietary intake or serum concentratio n of antioxidant (pro-) vitamins could attenuate the acute respiratory effe cts of air pollution in panels of adults (n=227) aged 50-70 yrs with chroni c respiratory symptoms in two winters starting in 1993/1994. Subjects performed daily peak expiratory flow (PEF) measurements in the mor ning and evening and reported the occurrence of respiratory symptoms in two regions turban and nonurban) each winter. Logistic regression analysis was used,vith the prevalences of large PEF decrements as dependent variables a nd air pollution levels as independent variables. Analyses were performed s eparately for subjects below and above the median levels of serum beta-caro tene and the intake of dietary vitamin C and beta-carotene. Subjects with low levels of serum beta-carotene more often had large PEF de crements when particles <10 mu m in diameter or black smoke levels which we re higher compared to subjects with high levels of serum beta-carotene. The same results tended to be observed for dietary vitamin C or beta-carotene, but there were less significant air pollution effects in the low dietary a ntioxidant group. The results suggest that serum beta-carotene and to a les ser extent dietary vitamin C and beta-carotene may attenuate peak expirator y flow decrements due to air pollution in subjects with chronic respiratory symptoms.