Environ Sci Pollut Res Int. 2023 Dec 27. doi: 10.1007/s11356-023-31504-6. Online ahead of print.

ABSTRACT

This study aimed to reveal harm of exposure to indoor air pollution to cognitive function through “gut-brain-axis” among rural elderly residents. There were 120 participants recruited in rural villages of northwest China from December 2021 to February 2022. The cognitive level was assessed by eight-item ascertain dementia (AD) questionnaire, and indoor air pollution exposure was measured by air quality sensor. Inflammatory cytokines and oxidative stress-related index were detected in blood serum. Fecal samples were collected for gut microbiota analysis. The 120 participants were divided into impaired cognition (AD8) (81/67.5%) and cognition normal (NG) (39/32.5%). And there had more female in AD8 (FAD) (55/67.9%) than NG (FNG) (18/46.2%) (P = 0.003). Exposure of air pollution in FAD was higher than FNG (PM₁, PM_2.5, PM₁₀, P < 0.001; NO₂, P < 0.001; CO, P = 0.014; O₃, P = 0.002). The risk of cognitive impairment increases 6.8%, 3.6%, 2.6%, 11%, and 2.4% in female for every 1 μg/m³ increased in exposure of PM₁, PM_2.5, PM₁₀, NO₂, and O₃, separately. And GSH-Px and T-SOD in FAD were significantly lower than the FNG group (P = 0.011, P = 0.019). Gut microbiota in FAD is disordered with lower richness and diversity. Relative abundance of core bacteria Faecalibacterium (top 1 genus) in FAD was reduced (13.65% vs 19.81%, P = 0.0235), while Escherichia_Shigella and Akkermansia was increased. Correlation analysis showed Faecalibacterium was negatively correlated with age, and exposure of O₃, PM₁, PM_2.5, and PM₁₀; Akkermansia and Monoglobus were positively correlated with exposure of PM₁, PM_2.5 and PM₁₀; Escherichia_Shigella was significantly positively correlated with NO₂. Indoor air pollution exposure impaired cognitive function in elderly people, especially female, which may cause systemic inflammation, dysbiosis of the gut microbiota, and ultimately leading to early cognitive impairment through the gut-brain axis.

PMID:38151560 | DOI:10.1007/s11356-023-31504-6