Dust events as a risk factor for daily hospitalization for respiratory and cardiovascular diseases in Minqin, China

Dust events are common air pollution events in parts of the world with arid, semi-arid, or desert areas. There is little research on the association between respiratory and cardiovascular health and dust events in places which are close to the deserts. The aim of this study is to evaluate the health effects of dust events in a location where traffic and industry are underdeveloped and dust events are most frequent in China. The setting allows the opportunity to reduce confounding by anthropogenically derived particulate matter and to confirm the health effects of dust events. The present study was done using daily counts of hospitalizations in Minqin (1994-2003) for respiratory and cardiovascular diseases (International Classification of Diseases, Tenth revision) for males and females. Using a semi-parametric generalized additive model and controlling for long-term temporal trends, day of the week, meteorological factors, and seasonal influence, counts of hospitalization were analyzed for dust events in a Poisson regression. Relative risks (RRs) were used to estimate the risk of dust events for respiratory and cardiovascular hospitalizations. In the year-round model, dust events with a lag of 3 days were significantly associated with total respiratory hospitalization for males and females, with RRs of 1.14 (95% confidence interval (CI) 1.01-1.29) and 1.18 (95% Cl 1.00-1.41); dust events with a lag of 4 days were significantly associated with upper respiratory tract infection (URTI) in males (RR 1.28, 95% Cl 1.04-1.59), and dust events with a lag of 6 days were significantly associated with pneumonia in males, with an RR of 1.17 (95% CI 1.00-1.38). A significant association between dust events with a lag of 3 clays and hypertension in males was also found (RR 1.30, 95% CI 1.03,1.64). In the seasonal analysis model, the associations between the dust events and respiratory and cardiovascular hospitalizations were stronger in spring and in winter, respectively. The results show the health effects of dust events on respiratory and cardiovascular hospitalizations, and the characteristic seasonal distribution of the health effects. In addition, the health effects of dust events are consistent with recent animal and human data showing the respiratory and cardiovascular effects of particulate matter. (c) 2007 Elsevier Ltd. All rights reserved.