Associations between PM_2.5 exposure and Alzheimer's Disease prevalence Among elderly in eastern China

Studies showed that PM_2.5 might be associated with various neurogenic diseases such as Alzheimer's Disease (AD). However, this topic had been little studied in Zhejiang province of China.  METHODS: In 2018, we established a cohort of AD high-risk population with 1,742 elderly aged 60 and above. In 2020, the cohort was followed up, a total of 1,545 people participated the 2 surveys. Data collection included questionnaires and basic physical examinations. The average residential exposure to PM_2.5 for each participant, that in a 5-years period prior to the first survey, was estimated using a satellite-based spatial statistical model. We determined the association between PM_2.5 and AD prevalence by cox proportional hazards regression model.  RESULTS: This study showed that an increase in the PM_2.5 level was an important associated risk factor that contributed to AD. The average PM_2.5 exposure levels among the study population ranged from 32.69 μg/m³ to 39.67 μg/m³ from 2013 to 2017, which were much higher than 5 μg/m³ that specified in the WHO air quality guidelines. There was an association between PM_2.5 exposure and AD, and the correlations between PM_2.5 and Mini-Mental State Examination, Montreal cognitive assessment scale scores were statistically significant. An increase in the PM_2.5 level by 10 μg/m³ elevated the risk of AD among residents by 2%-5% (HR _{model 2-model 4} = 1.02 to 1.05, CI _{model 2-model 4} = 1.01-1.10). The subgroups of male, with old age, with low education levels, used to work as farmers or blue-collar workers before retirement, overweight and obese were associated with a higher effect of PM_2.5.

Reducing PM_2.5 exposure might be a good way to prevent AD.