Predisposing factors for the development of bronchial asthma in children under 15 years old in Yerevan, Armenia: a case-control study

Abstract

The objective of the study was to determine some of the predisposing factors for the development of bronchial asthma in children under 15 years of age in Yerevan and the research questions asked by the study were: are children with family history of bronchial asthma prone to develop the disease in childhood?; is there an association between exposure to indoor allergens and risk of the development of bronchial asthma in childhood? To answer the research questions a case-control study with one control for each case was chosen. Estimated sample size was equal to 134 participants for cases and controls each. Target population was children of Yerevan, Armenia, suffering from bronchial asthma. Cases were chosen from “Arabkir” Medical Center and controls were chosen by RDD (Random Digit Dialing). Telephone interviews with the interviewer-administered questionnaire were used for data collection procedures. Refusal rate was equal to 3% among cases and to 5% among controls. The outcome (dependant) variable was the confirmed diagnosis of bronchial asthma and the main covariates (independent variables) were family history and environmental factors. Potential confounders, such as age, gender and family monthly income as well as interactions were considered in the analysis. Study has revealed statistically significant association between family history on bronchial asthma ((OR=24.66; 95% CI [2.9-282.8]; p-value 0.004); presence of many old books in the library (OR= 4.03; 95% CI [1.7;9.1]; p value= 0.001); and absence of conditioning/ventilation system in the household (OR= 5.66; 95% CI [2.5-12.8]; p -value=0.000) and the risk of the development of bronchial asthma. Main study limitations were: selection, instrumentation, recall and information biases.