Investigation of indoor microbial pollutants in homes of asthmatic school-aged children

Some studies have reported various associations between indoor microbiological exposure and asthma in children. Although, little is known about the associations of potential determinants such as dwelling age, location of the house, smoke exposures, cleaning frequency, Etc., and aggravating asthma in children. This study examined indoor bacterial and fungal agents and potential determinants at home as a risk factor for asthma in children. Furthermore, the associations of biological agents with potential determinants were investigated. A case-control study was conducted among school children (aged 6–11 years) in the province of Ankara, Turkey. As case and control groups, 109 children with asthma and 130 age- and sex-matched healthy children were identified. The parents answered questions about the home characteristics and lifestyles of families. Dust samples were collected from children's living rooms and bedrooms, and endotoxin β-(1→3)-D-glucan, Aspergillus, and Penicillium spp. were measured in dust extracts. Associations between microbial markers, potential determinants, and risk factors for asthma were evaluated. Among the 109 children with asthma, the frequency of gender in the asthma group was approximately equal, and the asthma study children were, on average, eight years of age. The Childhood Asthma Control Test (ACT) score of 74.8% of the children in the asthma group was more than 19. There were no statistically significant differences in age and gender in asthma and control groups. The endotoxin level was an inverse risk factor for the presence of asthma (OR = 0.324, 95% CI: 0.155–0.677). According to multivariate logistic regression, a high β-(1→3)-D-glucan level was a risk factor for the presence of asthma (OR = 3.162, 95% CI: 1.101–9.028). Furthermore, high β -(1→3)-D-glucan level was a risk factor for asthma exacerbation (OR = 2.563, 95% CI: 1.076–6.106) (P value= 0.034). Among the potential determinants that fitted multivariate modeling, dwelling age (˃20), house floor (≤1), new furniture at home, smoke exposures at home, and houses without a separate kitchen are risk factors for the presence of asthma. All associations with Aspergillus and Penicillium were statistically nonsignificant in multivariate logistic modeling. According to multivariate logistic regression analyses dwelling age (˃20), house floor (≤1) were determined as risk factors for uncontrolled asthma. Multivariate logistic regression analyses to determine the association between potential determinants and biological markers showed that having houseplants at home and the frequency of changing coverlets and bedsheets were the factors that were significantly associated with most of the biological markers.