Prevalence of Asthma and Asthma-Related Symptoms Among Adults Exposed to Indoor Environmental Risk Factors: a Comparison between Winter and Summer in Zunyi, China

Weather and climate are known to infl uence human health. Seasonal changes of temperature promote alterations in respiratory morbidity and in total and cause-specifi c mortality. Data on the prevalence of asthma and asthma-related symptoms and its disparities between winter and summer in the acid rain-plagued city of Zunyi in southwestern China have not been widely available. In order to describe the epidemiology of asthma and asthma-related symptoms and its prevalence changes between winter and summer, we have completed two cross-sectional surveys of people aged ≥18 years in winter and summer in the inner-city areas of Zunyi city, Guizhou Province, China. The subjects were selected using a simple random sampling method. Data on asthma and asthma-related symptoms and selected home environmental factors were assessed by questionnaire. The studied Chinese adult population residing in Zunyi recorded a lower prevalence rate of asthma than those of Western countries. There was signifi cant difference in asthma prevalence among adult respondents between winter (1.8%) and summer (0.8%) in inner-city Zunyi. Asthma and asthma-related symptoms occurred more frequently in winter than summer, and that difference mainly correlated with environmental risk exposures, including coal combustion, frequency of stove cooking, fan or range hood usage, mattress material, pet possession, must and mould in the bedroom, etc. The prevalence of adult asthma and asthma-related symptoms was higher in winter compared to the summer in Zunyi, China. Our study suggests that asthma may be an important component of the public health burden of indoor air pollution, especially in winter.