Prevalence and factors associated with exercise-induced bronchospasm among rural school children in Ilesa, Nigeria

Exercise-induced bronchospasm (EIB) assessed using changes in peak expiratory flow rates (PEFRs) to free range exercise is a relatively cheap way of screening for asthma in resource-poor centres where children with asthma are often undiagnosed and poorly managed. This study sets out to determine the prevalence and factors associated with EIB among rural schoolchildren in Ilesa, Nigeria.

Children aged 8-16 years from two middle schools in rural Ilesa were selected by multistage sampling. Their sociodemographic characteristics and personal/family history of asthma and allergies were obtained. The children had their PEFR measured before, 5, 10 and 15 min after 6-8 min of free running exercise to achieve 80% of their maximal pulse rate. EIB was defined as change in PEFR expressed as a percentage of the pre-exercise value ≥15%. The prevalence and factors associated with EIB were determined.

The mean (standard deviation) age of the 250 study participants was 12.5 (1.5) years (M: F 0.9:1) None of the children had previously been diagnosed with asthma. The prevalence of EIB was 9.2%, 6.4% and 4.0% at 5, 10 and 15 min post-exercise, respectively. Household poultry birds, personal history of allergies, wheeze in the past 12 months and family history of asthma were associated with EIB (P < 0.05); only wheezing in the past 12 months independently predicted EIB (odds ratio = 6.343; 95% confidence interval = 2.040-8.798; P= 0.020).

The prevalence of EIB among rural schoolchildren in Ilesa was 9.2%. EIB was associated with the history of allergies and wheeze and presence of household poultry birds. We recommend routine screening of these children for early diagnosis and good asthma symptom control.