Association between serum 25-hydroxyvitamin D levels and cognitive function among older adults in Tianjin, China: a cross-sectional community-based study

Abstract

Objective To explore the association between serum 25-hydroxyvitamin D (25-OH-D) levels and mild cognitive impairment (MCI) and further analyse the association between serum 25-OH-D levels and different dimensions of cognitive function. Design Cross-sectional study. Setting Tianjin, China. Participants A total of 866 participants aged 65 and above were enrolled in this study. Outcome MCI was diagnosed based on the revised Petersen diagnostic criteria. Cognitive function was assessed by the Wechsler Adult Intelligence Scale Revised in China. Results The prevalence of MCI was 12.0%. Higher serum 25-OH-D levels were significantly associated with lower odds of MCI, as well as with MCI across all subgroups (p<0.05). Serum 25-OH-D levels were significantly and positively associated with full intelligence quotient (FIQ), verbal intelligence quotient (VIQ), information, similarity and vocabulary (p<0.05). The associations between serum 25-OH-D levels and cognitive function did not significantly differ by age, gender or education level, with no statistical evidence of interactive effects. Conclusion Higher serum 25-OH-D levels were significantly associated with lower odds of MCI. Furthermore, serum 25-OH-D levels were significantly and positively associated with different dimensions of cognitive function, specifically FIQ, VIQ, information, similarity and vocabulary. There was no statistically significant interaction observed between serum 25-OH-D levels and age, gender or education level.