[The effect of short-term exposures to atmospheric fine particulate matter and its components on cognitive function...

Objective: To assess the effect of short-term exposures to atmospheric fine particulate matter (PM_2.5) and its components on cognitive function in middle-aged and older people aged 40-89 and identify key components that affect cognitive function. Methods: From October 2018 to March 2019, a cross-sectional survey of middle-aged and older people aged 40-89 was conducted across 10 cities in Beijing-Tianjin-Hebei and neighboring regions of China. Data on PM_2.5 and its components were collected from the nearest air supermonitoring stations to the residential addresses. The cognitive function was assessed using the Min-Mental State Examination (MMSE) scale. Multiple linear regression models were used to assess the effect of short-term exposures to PM_2.5 and its components on cognitive function in middle-aged and older people. The restricted cubic spline function was used to fit the exposure-response relationship between different components and changes in MMSE scores. Results: The age of the 1 978 respondents was (65.1±13.4) years, and 976 (49.34%) were males. During the study period, the daily mean concentration of PM_2.5 was (71.2±43.2) μg/m³, and the MMSE score was (28.2±3.7). The results of the multiple linear regression model showed that short-term exposures to PM_2.5 and its components were associated with cognitive decline in middle-aged and older people after adjusting for confounding factors, and the effect was higher at lag 0-28 days. For an interquartile range (64.3 μg/m³) increase in PM_2.5 at lag 0-28 d, the MMSE score decreased by 5.91 (95%CI: 0.04, 11.77). For an interquartile range increase in organic carbon (OC), antimony (Sb), chromium (Cr), zinc (Zn), tin (Sn), and cadmium (Cd), the MMSE scores of middle-aged and older people decreased by 5.71 (95%CI: 1.69, 9.73), 4.67 (95%CI: 2.50, 6.84), 4.49 (95%CI: 1.05, 7.92), 3.65 (95%CI: 0.89, 6.42), 2.76 (95%CI: 1.22, 4.30), and 1.72 (95%CI: 0.53, 2.92). Conclusions: Short-term exposures to atmospheric PM_2.5 and its components (OC, Sb, Cr, Zn, Sn, and Cd) are associated with cognitive decline in middle-aged and older people.