Air Pollution During Lockdown May Lead To Accelerated Cognitive Decline

Have you ever considered air pollutionduring lockdown? Recently, Professor Jintai Yu of Huashan Hospital, FudanUniversity, together with several internationally and nationally renownedscholars, estimated the risk effects of three common air pollutants, includingfine particulate matter (PM2.5), ground-level ozone and nitrogen dioxide, atdifferent exposure concentrations in different time windows, revealing that long-termexposure to PM2.5 significantly accelerates the deterioration of cognitivefunction, and that premature onset of Alzheimer's disease (AD) may occur in thebrains of highly exposed residents with air pollution This study has beenpublished in BioPsychiatry. The study was published in Biological Psychiatry.

Scientists explore air pollution duringlockdown. "Nine million people (equivalent to one-sixth of global deaths)will die from pollution in 2019, with air pollution accounting for nearly 75percent of these deaths." Jintai Yu described, "As our populationages, the incidence of dementia is also increasing year by year. Consideringthe global heterogeneity of different national conditions, ethnic groups,follow-up time and residual confounding, it has become a hot topic toinvestigate the effects of air pollution on different populations and differentstages of cognitive decline, and in vivo biological mechanisms."

However, the effects of air pollution onthe pathogenesis of AD have not been best interpreted due to the scarcity ofcerebrospinal fluid (CSF) or positron emission tomography (PET) scans. Yu'steam conducted a multi-level study of these issues based on the ChinaLongitudinal Healthy Longevity Survey (CLHLS) cohort, the earliest and longest-heldsocial science survey in China, and using the large-scale domesticneurobiological China Alzheimer's Disease Biomarker and Lifestyle (CABLE) studythat it led to establish. Some experiments verify air pollution duringlockdown.

In collaboration with the teams of HaidongKan and Renjie Chen, professors at the School of Public Health, FudanUniversity, Yi Zeng, professor at Peking University, Qiushi Feng and Lei Feng,professors at the University of Singapore, Huashuai Chen, professor at XiangtanUniversity, and Lan Tan, professor at Qingdao University, Yu's team studied31573 CLHLS participants (5878 in the follow-up cohort with a mean follow-uptime of 5.95 ± 2.87 years) and 1131 participants receiving AD CSF The study ofthe core pathological protein measurement CABLE population found that the riskof developing cognitive impairment increased by 10% for every 20 μg/m3 increasein PM2.5 exposure.

We get some studies about air pollutionduring lockdown. "This high risk is independent of the effects of commongenetic factors. Similarly, residents exposed to ozone and nitrogen dioxidepollution were more likely to experience deterioration in cognitive function,although both did not reach statistical significance." Yu added, "Forresidents living in areas with high levels of PM2.5 pollution, who haveaccelerated changes in scale scores reflecting overall cognitive function,premature AD pathological changes may occur in their brains."

The key contribution of using large-scalebiomarker data is to provide evidence that AD pathology may mediate themechanisms of PM2.5-associated cognitive decline, the investigators noted. Inaddition, air pollution-induced neuroinflammation and oxidative stress canexacerbate the burden of AD pathology or directly cause damage to criticalareas of brain tissue. Structural changes in the brain (e.g., brain atrophy)may be responsible for air pollution-related cognitive decline. Other mediatingfactors (e.g., stroke, coronary heart disease, etc.) may also underlie theassociation between air pollution and elevated risk of cognitive impairment.

Jintai Yu introduced that the prevalence ofAlzheimer's disease is increasing as China's population ages, but the impact ofair pollution on the pathogenesis of Alzheimer's disease has not been optimallyinterpreted due to the scarcity of key biological samples such as cerebrospinalfluid. Jintai Yu's team has systematically conducted a multi-level study ofthese issues using the China Longitudinal Healthy Longevity Survey (CLHLS)cohort of social science surveys and applying data from the large-scaleneurobiological China Alzheimer's Disease Biomarkers and Lifestyle (CABLE)study that it led to establish. The research team used the Intelligent MentalStatus Examination Scale for cognitive functioning scores.

Studies have confirmed that residents withlong-term exposure to ambient air pollution are at significantly higher risk ofcognitive decline. Moreover, AD pathological changes can occur prematurely inthe brain of highly exposed groups, thus accelerating the process of cognitivedecline. The researchers suggest that these findings have policy implications,namely that reducing exposure to air pollutants (especially PM2.5) could haveconsiderable health social benefits at the national level.