Mediation Effect of Oxidative Stress on Association Between Selenium Intake and Cognition in American Adults

Objectives: Dementia affects millions of aged people globally and mainly results from oxidative stress. Selenium shows beneficial effects on dementia however it remains elusive for the mediation effect of oxidative stress on the association between selenium and cognition. The present study firstly investigated the potential mediation role of oxidative stress on the relationship of selenium and cognition. Methods: A total of 2154 adults aged 60 years and older from the National Health and Nutrition Examination Survey 2011–2014 were selected for the study. Weighted multivariate linear regression, weighted logistic regression, and mediation effect analysis were employed to investigate the association among selenium intake, cognition, and oxidative stress. Results: Selenium intake was positively associated with cognition, albumin, and vitamin D, negatively associated with uric acid, and exhibited no correlation with gamma glutamyl transpeptidase (GGT). Cognition was positively correlated with albumin and vitamin D, negatively related to GGT, and had no association with uric acid. Albumin and vitamin D significantly mediated the relationship between selenium intake and cognition, and the mediation proportion values of albumin and vitamin D were 3.85% and 8.02%, respectively. Conclusions: For the first time, our findings demonstrated that higher selenium intake decreased cognitive impairment and oxidative stress levels. Moreover, the relationship between selenium intake and cognition was mediated by oxidative stress.