Abstract
BACKGROUND: Most studies that analyze the association between serum folate levels and cognitive function either restrict their assessments to specific clinical scenarios or do not include middle-aged individuals, to whom strategies for preventing cognitive impairment may be more feasible. OBJECTIVE: To examine the association between serum folate levels and cognitive function in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) baseline assessment. METHODS: Data from 4,571 ELSA-Brasil participants who live in the state of São Paulo, aged 35-74 years, were analyzed. The word list learning, delayed recall, word recognition, verbal fluency, and Trail Making Test Part B consisted in the cognitive tests. For each test, age, sex, and education-specific standardized scores and a global cognitive score were calculated. Crude and adjusted linear regression models were used to examine the associations of serum folate levels with cognitive test scores. RESULTS: In multivariable-adjusted models, serum folate was not associated with global cognitive score (β=-0.043; 95% confidence interval [95%CI] -0.135 to 0.050 for lowest vs. highest quintile group), nor with any cognitive test performance. We did not find associations between serum folate and global cognitive scores in subgroups stratified by age, sex, or use of vitamin supplements either. CONCLUSIONS: We did not find significant associations between serum folate and cognitive performance in this large sample, which is characterized by a context of food fortification policies and a consequent low frequency of folate deficiency. Positive results from previous studies may not apply to the increasingly common contexts in which food fortification is implemented, or to younger individuals.