Prevalence of asthma and respiratory symptoms in children in a low socio-economic status area of Nigeria.

SETTING: Warri and environs in the Niger Delta, in the Southern region of Nigeria. OBJECTIVE: To investigate the burden of respiratory illness in children in the Niger Delta. DESIGN: A cross-sectional survey of 1397 schoolchildren aged 7-14 years in areas of low socio-economic status (SES), using written questionnaires in English based on the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, with explanation of symptoms. RESULTS: The prevalence of doctor-diagnosed asthma was 0.9% (95%CI 0.4-1.3), and wheeze in the last 12 months was 5.4% (95%CI 4.3-6.6). The prevalence of other respiratory symptoms was high, in particular night cough 23.3% (95%CI 21.1-25.5), rhinitis 19.2% (95%CI 17.1-21.3) and phlegm production 16.6% (95%CI 14.7-18.6). Risk of wheeze in the younger age groups was twice (OR 2.09, 95%CI 1.29-3.39) that of older ages after controlling for sex and geographical area. Risk of asthma in urban children was reduced (OR 0.15, 95%CI 0.05-0.50) compared to rural children after controlling for age and sex. Urban children also had a lower risk of rhinitis, exercise limitations and absenteeism due to respiratory illness than rural children. CONCLUSION: The prevalence of symptoms of allergic disease was lower than in the African centres in the ISAAC surveys conducted in urban centres. Doctor-diagnosed asthma is likely to be a poor indicator of asthma in low SES areas of developing countries due to health care access issues.