Gender and season disparities in the influence of short-term fine particulate matter exposure on emergency room visits for mood disorders in Taiwan

Objective: This study examined the short-term effects of fine particulate matter (PM 2.5 ) exposure on emergency room (ER) visits for mood disorders, specifically bipolar disorder (BD) and depressive disorder (DD), in Taiwan. Methods: A time-stratified case-crossover design combined with distributed lag non-linear models was used to analyze data from the Taiwan Ministry of Environment and the Chang Gung Research Database (2010-2020). Results: Among 2,172 identified ER visits, PM 2.5 exposure was significantly associated with increased risks of BD/DD-related ER visits exclusively during the hot season, with significant associations observed among females. Both delayed and cumulative effects were observed at lag days 3-5 and cumulative lag periods of 0-1 and 0-3 to 0-5. Conclusions: Short-term PM 2.5 exposure was associated with increased risks of BD/DD-related ER visits, with effects observed exclusively during the hot season and predominantly among females.