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 concentration of antioxidant (pro-) vitamins could attenuate the acute respiratory effects of air pollution in panels of adults (n=227) aged 50-70 yrs with chronic respiratory symptoms in two winters starting in 1993/1994. Subjects performed daily peak expiratory flow (PEF) measurements in the morning 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 and air pollution levels as independent variables. Analyses were performed separately for subjects below and above the median levels of serum beta-carotene and the intake of dietary vitamin C and beta-carotene. Subjects with low levels of serum beta-carotene more often had large PEF decrements when particle