Hospital admission risks and ambient fine particulate matter exposure in Beijing, China

To estimate the impact of short- and long-term exposure to PM2.5 on hospital admission (HA) risks of circulatory diseases, respiratory diseases, mental disorders, endocrine and metabolic diseases, allergic diseases, urogenital diseases and malignant tumors respectively in an exposed population (by gender and age groups). Based on the data of ambient PM2.5 concentration and HAs in Beijing from January 1, 2013 to December 31, 2014, the spatial-temporal method is employed for a mixed Poisson regression model to integrate both short- and long-term exposure simultaneously when estimating the risk of HAs in the whole and subgroup population. The HA risks of mental disorders, urogenital diseases, diabetes and malignant tumors of the exposed population were associated with higher short-term ambient PM2.5 exposure. Positive associations between long-term PM2.5 exposure and the HAs were found for ischemic stroke, respiratory diseases, endocrine and metabolic diseases, allergic diseases, urogenital diseases, and malignant tumors (except lung cancer). The estimates of PM2.5-HA associations varied by sex and age groups. Ambient PM2.5 levels were positively associated with previously identified causes of HAs such as circulatory and respiratory diseases, as well as several prevalent but rarely studied diseases such as mental disorders, endocrine and metabolic diseases, allergic diseases, urogenital diseases, and malignant tumors (except lung cancer). The health losses caused by PM2.5 exposure could be underestimated if only circulatory and respiratory diseases were considered. Sex and age were modifying factors for the PM2.5-HA associations.