25-Hydroxyvitamin D, APOE ε4 genotype and cognitive function: findings from the 1958 British birth cohort

Both high and low vitamin D statuses have been associated with lower memory function. Apolipoprotein E (APOE) epsilon 4 alleles have been associated with reduced memory function, and separately with higher vitamin D concentrations. This report aims to examine if the presence of APOE epsilon 4 alleles contributes to the relationship between vitamin D and memory function. A total of 4848 (46% female) participants from the 1958 British birth cohort had information on APOE genotypes and completed memory tests at 50 years, where 4644 also had 25-hydroxyvitamin D (25(OH) D) concentrations measured at 45 years. Both low and high 25(OH) D concentrations were associated with lower memory function after adjustment for number of APOE epsilon 4 alleles (P-curvature = 0.02). There was evidence of interaction between APOE epsilon 4 and 25(OH) D, suggesting the association between 25(OH) D concentrations and memory function is different for those with two APOE epsilon 4 alleles compared with those with zero or one APOE epsilon 4 alleles (recessive model P-interaction = 0.01). Among participants with two APOE epsilon 4 alleles, higher 25(OH) D concentrations were associated with higher memory function, whereas in others, memory scores were slightly lower for individuals with higher versus lower concentrations. Further studies are required to replicate these findings.