Diet quality, asthma and airway inflammation in school-aged children.

Summary: Background. Asthma is a major public health problem, with increasing prevalence in most countries, particularly among children. Poor dietary quality is also increasing in children, and evidence of the overall quality of children's food patterns effects on asthma is scarce. Methods. This cross-sectional analysis (660 children: 49.1% females, aged 7-12years) evaluated the association between diet quality and asthma (n = 56) and airway inflammation among school-aged children according to body mass index (BMI). Diet quality was assessed through the Healthy Eating Index (HEI)-2015, and categorized by tertiles. Higher scores represent a healthier diet. A questionnaire was used to enquire about self-reported medical diagnosis of asthma and asthma under medication. Lung function and airway reversibility were measured, and airway inflammation assessed measuring exhaled fractional nitric oxide (eNO). Two categories of BMI were considered: non-overweight/obese (p less than 85^th), (n = 491), and overweight/obese (p ≥ than 85^th), (n = 169). The associations between diet quality and asthma and airway inflammation were estimated using logistic regression models. Results. Non-overweight/obese children in 2^nd tertile of HEI-2015 score had decreased odds of having eNO ≥ 35ppb (OR 0.43, 95%CI 0.19-0.98), medical diagnosis of asthma (OR 0.18; 95%CI 0.04-0.84), and asthma treatment (OR 0.12; 95%CI 0.01-0.95), compared to children in the 1^st tertile. Conclusions. Our findings suggest that a higher diet quality associates with lower levels of airway inflammation and reduced prevalence of asthma among non-overweight/obese school-aged children.