Genetics and environmental risk factors associated with asthma in schoolchildren.

OBJECTIVES: The objective of this study was to investigate the genetic and environmental risk factors associated with asthma among Qatari school children aged 6-12 years.
DESIGN: A cross-sectional study was performed. The International study of asthma and allergies in childhood (ISAAC) and some additional questionnaires were used to collect the data of the school children between Feb 2003 and Feb 2004.
SETTING: Government primary schools in the State of Qatar.
SUBJECTS: A multistage sampling design was used and a representative sample of 3500 children were targeted for this study. Of these, 3204 parents (91.6%) of the children agreed to participate in this study.
RESULTS: Of the total study sample 3204 school children living in urban and semi urban areas, 51.9% were boys and 48.1% girls. Their mean age was 8.92 +/- 1.89. The population sample had a high prevalence rate of asthma (19.8%) and allergic rhinitis 30.3%. The frequency of asthma, allergic rhinitis and eczema among parents reflected the same pattern as that seen in the children. Environmental risk factors associated with asthma were pets at home, allergic to certain food or medicine, smoking history among parents or elder siblings (p<0.0001). A stepwise logistic regression analysis results showed that allergic to food and medicine, history of asthma in father, mother, siblings and asthma in second degree relatives and smoking habit of father were significant predictors for asthma after adjusting age and sex and other confounding covariates in the model.
CONCLUSION: The present study revealed that the family history of asthma contributed more to childhood asthma than indoor and outdoor environmental factors. Boys were found more asthmatic than girls. The results of this study support the hypothesis that asthma is a multi-factorial disease related to both familial and environmental influences.