Causal effects of prenatal and chronic PM 2.5 exposures on cognitive function

• Published in: Environmental research Vol. 219; p. 115138
• Main Authors: Ke, Limei, Feng, Guoqing, Zhang, Yao, Ma, Xindong, Zhao, Bin, Sun, Yisheng, Dong, Zhaoxin, Xing, Jia, Wang, Shuxiao, Di, Qian
• Format: Journal Article
• Language: English
• Published: Netherlands 15.02.2023
• Subjects: Adult; Air Pollutants - analysis; Air Pollutants - toxicity; Air Pollution - adverse effects; Air Pollution - analysis; Cognition; Environmental Exposure - adverse effects; Environmental Exposure - analysis; Female; Humans; Particulate Matter - analysis; Particulate Matter - toxicity; Pregnancy; Vitamins; Causal inference; PM(2.5); Adulthood cognition; Prenatal exposure; Chronic exposure

Growing evidence indicated an association between PM exposure and cognitive function, but the causal effect and the cognitive effect of prenatal PM exposure remain elusive. We obtained 15,099 subjects from a nationally representative sample of China and measured their cognitive performance. We ascertained subjects' prenatal PM exposure and chronic PM exposure of the recent two years. Using this national sample, we found that PM exposure during the mid- to late-pregnancy was significantly associated with declined cognition and income; chronic PM exposure was also independently associated with cognition and income measured at adulthood with greater magnitude. Negative effect modification was observed between prenatal and chronic PM exposure. Instrumental variable approach and difference-in-difference study verified causal effects: every 1 μg/m increase in prenatal and chronic PM exposures were causally associated with -0.22% (-0.38%, -0.06%) and -0.17% (-0.31%, -0.03%) changes in cognitive function, respectively. People with low cognition and low income were more vulnerable to PM exposure with greater cognitive and income decline. In the future, although China's improved air quality continues to benefit people and reduce cognitive decline induced by chronic PM exposure, high prenatal PM exposure will continue to hurt the overall cognition of Chinese population, since in total 360 million people were born during the 2000-2020 polluted era. Prenatal PM -induced cognitive decline would remain largely unchanged before 2050 and gradually reduce after 2065, regardless of environmental policy scenarios. The long-lasting cognitive impact of PM is worth considering while enacting environmental policies.