Indoor environment in relation to recurrent childhood asthma in Yancheng, China: a hospital-based case-control study

This investigation explored the association between indoor environmental factors and childhood asthma in Yancheng, China. Asthma case (201 children with recurrent asthma) and control cohorts (242 healthy subjects) were recruited from a Traditional Chinese Medical (TCM) Hospital in Yancheng city, based on the results of an ISAAC questionnaire. Questionnaires regarding environmental risk factors were completed by the child’s primary caregivers. To compare data on environmental VOCs and formaldehyde contents between asthma and control cohorts, we passively conducted a 10-day indoor and outdoor sampling. Breastfeeding was a major protective indoor environmental factor for recurrent asthma (adjusted odds ratio [aOR]: 0.368, 95% confidence interval [CI]: 0.216–0.627). Our analysis revealed that childhood recurrent asthma was intricately linked to a family history of asthma. Recurrent asthma was also associated with passive smoking [aOR2.115 (95%-CI 1.275–3.508)]. Analogous correlations were observed between household renovation or new furniture introduction and recurrent asthma [aOR3.129(95%-CI1.542–6.347)]. Benzene and formaldehyde were present in all examined homes. Enhanced benzene and formaldehyde concentrations were strongly evident among asthma versus control cohorts, and they were strongly correlated with augmented recurrent asthma risk. Home environment heavily regulates incidences of childhood recurrent asthma. Hence, actions against the indoor environmental risk factors described in this study may assist in the prevention of recurrent asthma among children.