Abstract

BACKGROUND A study was undertaken to investigate the relationships between the intake of the antioxidant (pro)-vitamins C, E and β-carotene and the presence of respiratory symptoms and lung function.

METHODS Complete data were collected in a cross sectional study in a random sample of the Dutch population on 6555 adults during 1994 and 1995. Antioxidant intake was assessed by a semi-quantitative food frequency questionnaire and respiratory symptoms (cough, phlegm, productive cough, wheeze, shortness of breath) were assessed by a self-administered questionnaire. Prevalence odds ratios for symptoms were calculated using logistic regression analysis. Linear regression analysis was used for forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC). The results are presented as a comparison between the 90th and 10th percentiles of antioxidant intake.

RESULTS Vitamin C intake was not associated with most symptoms but was inversely related with cough. Subjects with a high intake of vitamin C had a 53 ml (95% CI 23 to 83) higher FEV₁ and 79 ml (95% CI 42 to 116) higher FVC than those with a low vitamin C intake. Vitamin E intake showed no association with most symptoms and lung function, but had a positive association with productive cough. The intake of β-carotene was not associated with most symptoms but had a positive association with wheeze. However, subjects with a high intake of β-carotene had a 60 ml (95% CI 31 to 89) higher FEV₁ and 75 ml (95% CI 40 to 110) higher FVC than those with a low intake of β-carotene.

CONCLUSIONS The results of this study suggest that a high intake of vitamin C or β-carotene is protective for FEV₁ and FVC compared with a low intake, but not for respiratory symptoms.