Antioxidant foods consumption and childhood asthma and other allergic diseases: The Greek cohorts of the ISAAC II survey.

BACKGROUND: Antioxidant intake changes have been implicated with the increase in asthma and allergies outcomes, but no clear association has been revealed. In this cross sectional study, the overall effect of antioxidants on asthma and allergic diseases was studied. METHODS: Data from the cohorts of the phase II ISAAC survey (2023 children 9-10 years old) in two metropolitan Greek cities were analysed. Using a semi-quantitative food frequency questionnaire, an Antioxidant Eating Index (AEI, range 0-6) was created with the pro-antioxidant (vegetables, fruits, fresh juice, fish) and the non-antioxidant (meat, burgers) food intake and was evaluated with allergic diseases. Higher values of the score suggest closer to an "antioxidant" and lesser to a "saturated fatty" diet. RESULTS: Prevalence of lifetime and current asthma, current rhinitis and sensitisation were higher in Thessaloniki compared to Athens. The AEI score of the entire cohort was 4.2 ± 1.2 (median 4.0) and was higher in Athens compared to Thessaloniki (4.3 ± 1.2 vs. 4.0 ± 1.2, p=0.001) and in girls than boys (4.3 ± 1.1 vs. 4.0 ± 1.2, p=0.001). AEI was inversely associated with lifetime asthma (OR: 0.87, 95%CI 0.77, 0.99) in either cities independently of other cofounders such as family history, sensitisation, exercise, house smoking, breast feeding, pet or dampness in houses. No association with other allergic disease or sensitisation was detected. CONCLUSION: Antioxidant foods seem to be a non-pharmacological, protective dietary pattern for asthma development in children irrespectively of atopy or heredity; AEI was a rough indicator and the role of antioxidants in allergic diseases is still under consideration.

Comparison in asthma and allergy prevalence in the two major cities in Greece: the ISAAC phase II survey.

BACKGROUND: Variability in the prevalence of allergic diseases has been detected not only between different countries, but also between cities with similar national and different socio-economic or climatic characteristics. The aim of this study was to determine the prevalence of childhood asthma and allergies and which factors are associated with them, in the two largest Greek cities, Athens and Thessaloniki. METHODS: Two thousand and twenty-three Greek 9-10-year-old schoolchildren from Athens (Central Greece) and Thessaloniki (North Greece, more humid), were included in ISAAC-II study. All participants followed the ISAAC-II protocol by questionnaire, skin prick testing and flexural dermatitis examination. RESULTS: Compared with Athens, the prevalence of current wheezing (8.4% vs. 5.7%, p=0.002), lifetime asthma (11.5% vs. 7.7%, p=0.004), atopic current asthma (3.2% vs. 1.6%, p=0.02), allergic rhinitis (8.2% vs. 5.2%, p=0.007), and hay fever (21.7% vs. 12.5%, p<0.001) were higher in Thessaloniki. The overall sensitisation rate was also higher in Thessaloniki than in Athens (25.2% vs. 16%, p<0.001) with more prevalent sensitising due to the perennial allergens (D. pteronyssinus, D. farinae, Alternaria tenuis) and cat dander. Perennial allergens sensitisation was a risk factor for current asthma in both cities. CONCLUSION: A higher prevalence of asthma symptoms, allergic rhinitis, and sensitisation rate was detected in Greek schoolchildren living in Thessaloniki compared to those in Athens. Allergy to mites and mould was more prevalent in Thessaloniki. The more humid weather of Thessaloniki may be implicated.