The effects of household air pollution due to burning of mosquito coils on respiratory problems in Myanmar migrant workers in Mae Sot district, Tak province, Thailand

Abstract

The objective of this cross-sectional study was to investigate whether household burning of mosquito coils is associated with increased risk of respiratory problems among Myanmar migrant workers in Mae Ku village, Mae Sot district, Tak Province, Thailand (total 500 households). 412 female respondents and 153 children under 7 years old were included. Data were collected using a standardized, pre-tested interviewer-administered questionnaire in March 2010. Prevalences of symptoms such as cough with or without colds, phlegm with or without colds, wheeze with or without colds, shortness of breath, sore throat without cold, rhinitis and eye irritation at home were assessed in relation to mosquito coil use and other 12 independent variables that could also be associated with respiratory symptoms. In a bivariate analysis, each independent variable was assessed separately in relation to each type of prevalence. For respondents and children, semifinal multiple logistic regression models were then constructed for all symptom types for which p is less than or equal to 0.15 for mosquito coil use in bivariate analysis. All other independent variables for which p is less than or equal to 0.15 were also included in these models. Final multiple logistic models were then constructed. In these, mosquito coil use was entered, as were all other independent variables for which p is less than or equal to 0.15 in semifinal models. Final logistic regression models showed that in respondents, mosquito coil use had positive significant associations with cough with or without colds (OR=1.84, 95% CI=1.02 to 3.33, p=0.045), phlegm with or without colds (OR=2.02, 95% CI=1.28 to 3.19, p=0.003), and wheeze with or without colds (OR=2.47, 95% CI=1.52 to 4.00, p<0.001). In children, there was a marginally significant positive association of cough with or without cold with mosquito coil use (OR=2.85, 95% CI=0.99 to 8.22, p=0.052). These results strongly suggest that mosquito coil burning is a respiratory risk factor in the study population, but do not prove causality. The observed associations should be investigated further. If they are confirmed, other methods of controlling exposure to mosquitoes (such as lemon grass) should be sought for preventing mosquito-borne diseases. Health and economic risks and benefits of mosquito coil burning should be characterized carefully before policy decisions are made