Dietary antioxidant intake in school age and lung function development up to adolescence

Abstract

Dietary antioxidant intake has been hypothesised to influence lung function. The association between total antioxidant capacity (TAC) of the diet at age 8 years and lung function development up to 16 years in 2307 participants from the Swedish population-based birth cohort BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiology) was investigated.Information on TAC was obtained from a food frequency questionnaire at 8 years. Lung function was measured by spirometry at 8 and 16 years, impulse oscillometry (IOS) and exhaled nitric oxide fraction (F _eNO) at 16 years. Low lung function was defined as forced expiratory volume in 1 s (FEV₁) z-score below the 25th percentile. Longitudinal associations between TAC and lung function were analysed by mixed effect models adjusted for potential confounders. Stratification by asthma at 8 years was performed to examine effect modification.The median TAC intake was 10 067 μmol Trolox equivalents (TE)·g^-1, with males having a lower mean compared to females (9963 versus 10 819 μmol TE·g^-1). In analyses of lung function change between 8 and 16 years, there were no statistically significant associations between TAC in tertiles and spirometry results for the total study population. Among children with asthma at 8 years (prevalence 7%), higher TAC was associated with higher mean FEV₁ (0.46 sd, 95% CI 0.11-0.80) and decreased odds of low lung function at 16 years (OR 0.28, 95% CI 0.12-0.65). There were no associations between TAC and forced vital capacity or IOS/F _eNO results.High dietary antioxidant intake in school age may be associated with improved lung function development from school age to adolescence among children with asthma.