The incidence of atopic dermatitis in school entrants is associated with individual life-style factors but not with local environmental factors in Hannover, Germany

BACKGROUND: Atopic dermatitis (AD) is a common skin disease in childhood. Micro- and macro-environmental factors have not yet been studied simultaneously in a large cohort of the same area in detail. OBJECTIVES: The incidence of AD was investigated in 97% of all school entrants (n = 4219) in the city of Hannover, Germany, with regard to the influence of individual and environmental factors. METHODS: A standardized questionnaire based on the criteria of Hanifin and Rajka that has the sensitivity and specificity of 97% compared with the clinical diagnosis of a dermatologist and a logistic regression model were used. Multiple local-based environmental factors were analysed for all 49 city quarters. RESULTS: Of all children studied, 10.5% suffered from AD at some time in their lives. The frequency of AD was significantly increasing with more privileged socio-economic status (P < 0.01). Independent factors that were associated with a higher frequency of AD were German nationality (12.4% AD compared with 2.1% in non-German), higher paternal socio-economic status (i.e. father's profession), higher daily duration of the fathers' professional work and the lack of paternal shift work. In contrast, there was no significant association between the frequency of AD and local environmental factors such as the biological effective level of air pollution and urbanization. CONCLUSIONS: In conclusion, we confirm an association between a privileged life-style and a higher incidence of AD in a large number of investigated children between 5 and 9 years of age (97.6% of children were 6 or 7 years old) for the German city of Hannover. We propose the socio-economic status as a marker for different life-styles and social micro-environments in further studies as there were multiple significant correlations between individual social and environmental factors. The macro-environment seems to be less important for the disease outcome in this context.