PM10 concentration in relation to clinic visits for anxiety disorders: a population-based study of a high river-dust episode region in Taiwan

PM₁₀ exposure has been found to have significant effects on a variety of physical conditions. However, whether it acts on psychopathology remains unclear. This study used 8-year data to examine the relationship between PM₁₀ concentration and daily clinic visits of anxiety disorders. All residents of Yunlin County, Taiwan, which is a high river-dust exposure area, were selected as subjects. Data from the Taiwan National Health Insurance Research Database (NHIRD), 2002–2009, were analyzed. Individuals with any ICD code of 300.0 and 300.2 were categorized as with anxiety disorders. PM₁₀ data were based on the Lunbei station (located at Yunlin County) of EPA, Taiwan. Time-series analysis showed that, during the observed 8 years, the number of daily clinic visits for anxiety disorders increased with PM₁₀ levels, and the relationship remained significant after unemployment rate, and the Weighted Price Index of Taiwan Stock Exchange in the same period were controlled for. In particular, we found that there is a linear dose-response effect between daily clinic visits and PM₁₀ levels when PM₁₀ 3; whereas a dramatically elevated daily clinic visits of anxiety disorders was found when PM₁₀ >?300 μg/m³. Findings from this study highlight that high level of PM₁₀ exposure derived from severe weather or environment condition may affect the occurrence of anxiety disorders. In addition, there seems to have a threshold of PM₁₀ in elevating the risk of anxiety disorders.