P3-124: Selenium and cognitive function in rural elderly Chinese

Background: Selenium is a trace element associated with the activity of the antioxidant enzyme glutathione peroxidase and is considered to be a protective agent against free radicals through enhanced enzyme activity. Associations between low selenium and increased risk in various disease indices including cancer, cardiovascular disease, reproduction and neonatal health, and asthma have been reported. The limited studies on selenium and cognitive function or Alzheimer’s disease, however, have not reached unequivocal conclusions. Objective: To examine the association between selenium levels and cognitive function in the elderly. Methods: A cross-sectional survey of 2000 rural Chinese age 65 and over from two provinces in China was conducted using the Community Screening Instrument for Dementia, CERAD Word List Learning test, a 14-item story recall, Animal Fluency test, and IU Token Test. Over seventy percent of study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Food frequency questionnaires were administrated while local food samples were collected and analyzed for selenium content. APOE genotype was determined using blood samples collected on filter cards. Analysis of covariance models were used to estimate the association between selenium levels measured in nail samples and from food intake and cognitive test scores adjusted for age, gender, education and APOE genotype. Results: Lower selenium levels measured in nail samples and from food intake were significantly associated with poor cognitive function as measured by various cognitive tests. Standardized beta coefficients range from 0.06 to 0.24 on all tests (p<0.01 for all) adjusted for age, gender, education level and APOE genotype. The APO ϵ4 allele was not significantly associated with any cognitive measures and there is no significant interaction between APOE and selenium levels. Conclusions: Our results support the hypothesis that low selenium level is associated with poor cognitive function. Longitudinal follow-up of this cohort will help to establish whether selenium levels affect the rate of cognitive decline associated with aging.