Association of arsenic exposure and cognitive impairment: a population-based cross-sectional study in China

Abstract Background: Chronic arsenic exposure is a major public health issue worldwide. Previous studies explored the effects of arsenic exposure on cognitive impairment, but majority of previous studies focused on the effects on school children rather than adults. Moreover, few studies investigated the role of arsenic exposure in cognitive impairment process in a large scale in China. Methods: Aimed to evaluate the association between long-term exposure to arsenic and cognitive impairment in China, we designed a cross-sectional analytical study in which 1,556 adults from three locations around the Realgar Plant (Heshan Village, Wangyangqiao Community and Baiyangshan Village) were enrolled. Participants’ general cognitive function were evaluated by using a Chinese version of Mini-mental state Examination (MMSE). Internal arsenic exposure status of participants (hair arsenic concentrations) was measured by inductively coupled plasma-mass spectroscopy (ICP-MS), and external arsenic exposure status of participants was approximately evaluated by measuring the distance between the participants’ location to Realgar Plant. Results: In our study, we found that the prevalence of cognitive impairment in arsenic-endemic areas was 20.6%, which was significantly higher than the prevalence of cognitive impairment in China (14.5%). Hair arsenic concentrations and prevalence of arsenicosis in cognitive impaired group (CI) was significantly higher than those in cognitive normal group (CN) (P<0.05). Conclusions: Our analyses revealed that the distance away from Realgar Plant was positively correlated with MMSE scores, while inversely associated with the prevalence of cognitive impairment. In addition, we found that MMSE scores were decreased with the increasing hair arsenic concentrations in a dose-dependent manner. In two-level Logistic regression analysis, arsenicosis was still a risk factor for cognitive impairment (odds ratio (OR) =1.77, P<0.05) even after adjusting for potential confounding variables. Our results showed that chronic arsenic exposure decreased cognitive function in adults in a dose-dependent manner, and arsenicosis was a risk factor for cognitive impairment.