Prevalence of Exercise induced bronchospasm in children

Background: Exercise- induced bronchoconstriction (EIB) is the term used to describe the transient narrowing of the airways that follow vigorous exercise. Unrecognized and uncontrolled symptoms of EIB can lead patients to avoid general and occupational physical activities and sports. The prevalence rate of EIB has been reported in some population studies but remains unknown in many Africans including Zambian pediatric population. Objectives: To estimate the prevalence and risk factors of exercise-induced bronchospasm (EIB) among a sample of school children aged 10 – 14 years in Lusaka (Zambia). Method: Two hundred and one (201) children aged 10 to 14 years randomly selected from 10 Lusaka urban schools completed a standard respiratory survey questionnaire. Each child participated in a standard 6-minute exercise test by free running and peak expiratory rate (PEFR) measurements were taken before, 5 and 10 minutes after exercise. A decrease in PEFR of 15% was considered positive for EIB.Results: There were 201 children (age: 12 +/- 1.4 yrs - mean +/- SD; 76 males and 125 females). The prevalence of EIB was 31/201(15.4%) at 5 minutes (mins) and 25/201 (12.4%) at 10mins. In logistic regression analysis, a family history of asthma (OR=11.805, 95% CI 2.120 – 65.722, p=0.005), atopy (OR=7.906), 95%CI 1.608 – 38.863, p=0.011) or both (OR=13.281, 95% CI 2.758 – 63.944, p=0.001) were strongly associated with a high risk of EIB. There were no significant differences in the prevalence of EIB according to sex (P = 0.9), BMI (P = 0.634) or past history of asthma (p=0.7).Conclusions: Our study suggests that the prevalence of EIB in our population is approximately within the range 12% to 15%. Risk factors include atopy & family history of asthma. Both BMI and age do not appear to have a positive correlation. Larger samples of children are needed.