Early childhood respiratory health effects of air pollution in the Czech Republic

Respiratory illnesses represent a significant disease burden in infants and young children worldwide. Studies have shown that young children are particularly vulnerable to air pollution's respiratory health effects. I have examined the associations between pediatrician-reported lower respiratory illnesses (LRI) and indoor- and outdoor-air pollution exposures during the first three years of life. I made use of morbidity and questionnaire information from a birth cohort of 452 children residing in two districts of the Czech Republic. Indoor combustion exposures included questionnaire-reported home heating and cooking fuel types, mother's smoking during pregnancy, and other household smokers. Outdoor measurements were daily-measured fine---(PM2.5) and coarse---(PM10--25) fraction particulate matter, polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides (NOX), and sulfur dioxide (SO 2).;In the analyses of indoor air exposures, I found that children living in homes with coal heating experienced more LRI diagnoses than did children living in homes with wood, natural gas, electric, central, or distant heating. Children of mothers who smoked during pregnancy had more LRI diagnoses, and children who lived in homes where other adults smoked also experienced greater LRI incidence, independent of mother's smoking. Among children who had never breastfed the effects of coal home heating (rate ratio (RR): 2.77; 95% confidence interval (CI): 1.45--5.27) were greater than among children who had breastfed (RR: 1.33; 95% CI: 0.95--1.86). The association between mother's smoking and LRI was also greater in those who never breastfed (RR: 2.52: 95% CI: 1.31--4.85) than in those who breastfed (RR: 1.37; 95% CI: 0.98--1.92).;In the analyses of outdoor pollutant exposures, I found that LRI incidence increased with increasing ambient concentrations of PM2.5, PM 10--25, PAHs and NOx, but not with SO2. Effect estimates were imprecise, but an overall pattern emerged, with LRI incidence increasing with elevated air pollutant levels on the same day and one or two days preceding diagnosis. I observed much stronger particle and PAH effects among children whose homes were heated with coal.;Overall, the study findings emphasize the importance of considering microenvironmental exposures when assessing the relationship between air pollution and respiratory illness in young children.