Prevalence and factors linked to atopy in 10-and 11-year-old children in Almería, Spain

During the last decades there has been an increase in both allergic diseases and allergic sensitisation, probably due to changes in the environment and living habits. ISAAC Phase II was designed to establish the prevalence and associated factors to asthma and allergic disorders in childhood.

To assess the prevalence and factors linked to atopy in 10-11 year-old children from Almería (Spain).

As a part of ISAAC II, a survey was conducted among a sample of 1143 schoolchildren using standardised questionnaires and skin-prick testing.

The overall prevalence of atopy was 42.5%. Most common sensitisations were to Dermatophagoides pteronyssinus (36.2%), D. farinae (32.3%), cat (10.8%), Alternaria (7%), grass (6%), and tree pollen (1.7%). 34.9% of these sensitisations could be regarded as subclinical sensitisations. The fractions of asthma, rhinitis and eczema attributable to atopy were 49.2%, 40.4% y 18.6%, respectively. After multivariate analysis, the risk of atopy was significantly lower among females (OR 0.62, CI 95% 0.45-0.86); children with older siblings (OR 0.67; CI 95% 0.49-0.92); intestinal parasites (OR 0.68; CI 95% 0.48-0.97); contact with farm animals in the past (OR 0.48 CI 95% 0.23-0.99); or other animals at present (OR 0.53 CI 95% 0.30-0.95). To have an allergic father (OR 2.96 CI 95% 1.77-4.94) was the only significant risk factor.

We found several independent factors which significantly protect against atopic sensitisation. These protective factors were not the same for asthma, rhinitis or eczema, suggesting that other factors could interact to influence atopy and act against such protective factors.