Abstract

The prevalence of asthma and allergies has increased sharply in past decades due to air pollution and urban lifestyles and environments. Cairo is one of the world‘s most polluted cities and suffers from heavy traffic. Previous studies have shown an association between the urban environment and the risk of developing asthma and allergic rhinitis (AR) in children and this study is the first longitudinal study to examine this with comparison between Cairo and a rural area, Shben El-Kom. The study made a long-term examination of FEV1, FVC and PEFR and also examined other risk factors associated with asthma eczema and AR. Methods: Two groups of school children were selected. One from inner-city Cairo, the other from the low-polluted rural area, Shben El-Kom in the Nile Delta region. The children were studied 5 times, with testing taking place every 6 months over a 2-year period using the ISAAC questionnaire. Measurements of air pollution at these cities were obtained. In addition, periodic measurements of lung-function were also made on some children who did not have asthma or a smoker living in the house from both locations. Results: Multilevel generalized mixed logistic regression 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. Generalized linear regression adjusted for confounders showed that living in Cairo was associated with decreased FVC, FEV1 and PEFR by 4.8% , (95% CL= 5%-7%) 6.2%, (95% CL = 6.3%-6%) and 6.8% (95% CL= 7%-6.6%) respectively. Significant differences were found in the changes occurring between the two locations in the last three visits, where Cairo showed statistically significant lower increases in FVC predicted%, FEV1predicted% and PEFR in both boys and girls. Conclusion: Children living in urban Cairo had a higher risk of allergic conditions, lower lung function and slower lung growth compared to 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.