Research on combined effects between ambient particulate matters (PMs) and Folate (FA) with respect to cognitive function remains limited. This study aimed to investigate whether long-term PMs exposure could modulate the association between FA and cognitive function in Chinese older adults. The study was composed of 3,880 individuals aged 60 and above. The cognition of the subjects was assessed using the Montreal Cognitive Assessment - Basic Version (MoCA-B). Folate concentration was measured through laboratory serum analysis, and data on ambient particulate matter levels were acquired from the China High Air Pollutant (CHAP) monitoring network. A linear regression analysis was conducted to explore how FA and PMs interact to affect cognitive function, with stratified analysis based on thresholds identified using restricted cubic splines (RCS). Based on the results of the linear trend analysis, PMs exposure exhibited a negative with MoCA-B scores (all P trend < 0.001); RCS analysis further revealed that the exposure-response relationships for PM 2.5 , PM 10 and MoCA-B scores exhibited significant non-linear characteristics ( P < 0.05), identifying their effect inflection points. FA was positively associated with MoCA-B scores ( β = 0.107, 95% CI : -0.073, 0.287), and this association was effect by PM 2.5 and PM 10 exposure levels: as their concentration increased, the positive association was attenuated; When the exposure concentration exceeded 64.54 µg/m³and 103.9 µg/m 3 , the association even replaced by a negative association. Our findings indicated that PM exposure were associated with an attenuated positive association between FA and cognitive function, and even a negative association.Therefore, further action must be taken to reduce the harm caused by air pollution to enhance the cognitive benefits of FA.
Y et al. (Tue,) studied this question.