Reported prevalence of allergy and asthma in children from urban and rural Egypt

Previous studies have shown an association between the urban environment and the risk of developing asthma and allergic rhinitis (AR) in children. This is the first longitudinal study to examine risk factors associated with asthma, eczema and AR in a comparison between Cairo, one of the world's most polluted cities, and a rural area, Shben El-Kom. Two groups of school children were selected. One group was from inner-city Cairo, and the other was from a low-polluted rural area, Shben El-Kom in the Nile Delta region. The children were studied four times, with testing taking place every 6 months over an 18-month period using the ISAAC questionnaire. Two generalized mixed logistic regressions showed that living in Cairo increased the risk of current wheeze, wheeze ever, asthma ever, current AR, AR ever, hay fever ever, current rash, rash ever and eczema ever. Other risk factors that effected asthma included maternal eczema, paternal asthma, maternal asthma and passive smoking. Exposure to farm animals decreased the odds of having asthma. Children living in urban Cairo had a higher risk of allergic conditions than those living in the rural area of Shben El-Kom. This was not fully explained by passive smoking, breastfeeding, parental allergy or exposure to animals.