Plasma concentrations of the antioxidants beta-carotene and alpha-tocopherol in relation to lung function

Objective: To study the association between plasma antioxidants (beta-carotene and alpha-tocopherol) and lung function in Dutch adults aged 20-59 y. Design: Cross-sectional. Setting: Population-based study. Subjects: A random sample (n = 367) was drawn from all participants (men and women) aged 20-59 y with reproducible lung function measurements in 1995. Intervention: Completion of general questionnaire and physical examination. Main outcome measurements: Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and plasma levels of beta-carotene and alpha-tocopherol. Results: Subjects with a high plasma beta-carotene level (90th percentile, that is 0.57 micromol/L) tended to have a higher FEV1 (73 ml, s.e.m. 60 ml; P = 0.22) and a higher FVC (147 ml, s.e.m. 76 ml: P = 0.05) than subjects with a low plasma beta-carotene level (10th percentile, that is 0.11 micromol/L) after adjustment for age, height, gender, smoking status, pack-years of smoking and alcohol consumption. There was no difference in lung function between subjects with high and low plasma alpha-tocopherol concentrations. Conclusions: The results suggest that subjects with a high plasma beta-carotene tended to have a higher FVC than subjects with a low plasma beta-carotene concentration which was borderline statistically significant. The difference for FEV1 between high and low levels of plasma beta-carotene tended to be in the same positive direction as that of FVC but did not reach the pre-set statistical significance level. There is no relation between plasma alpha-tocopherol and lung function.