Cross-sectional association of dietary patterns with asthma and atopic sensitisation in childhood – in a cohort study.

BACKGROUND
Many studies have investigated individual nutrients or foods as risk factors for allergic disease, but few have studied dietary patterns. We aimed to use principal component analysis (PCA) to determine dietary patterns in school age children and examine associations between these dietary patterns and wheeze, asthma and sensitisation.

METHOD
Participants in a population-based birth cohort attended review clinics at ages 8 and 11 years. Validated questionnaire was interviewer-administered to collect information on parentally-reported symptoms and doctor-diagnosed asthma. Atopic sensitization was ascertained by skin-prick tests. Current asthma was defined as doctor-diagnosed asthma and wheezing in the previous 12 months. Validated semi-quantitative food frequency questionnaire was completed at age 8 years, and PCA was used to determine dietary patterns.

RESULTS
PCA identified three dietary components, which based on their characteristics we termed as Traditional (mixed meat, fish, fruit and vegetables), Western (predominantly high fat content, processed foods) and Other (predominantly grains, nuts) dietary patterns. High adherence to the Western diet pattern was significantly associated with doctor-diagnosed asthma and current asthma at age 8 years (aOR [95% CI]: 2.19 [1.20-4.01], p=0.01; 2.59 [1.15-5.81], p=0.02; respectively). A similar association was found for current asthma at age 11 years (aOR [95% CI]: 2.20 [1.07-4.51], p=0.03). There was no evidence of an association between dietary patterns and current wheeze and allergic sensitisation at either age 8 or 11 years.

CONCLUSION
School age children adhering strongly to a Western diet, high in fat and processed foods, had a higher risk of current asthma and doctor-diagnosed asthma.