Vitamin D insufficiency and mild cognitive impairment: cross-sectional association.

BACKGROUND: Low serum 25-hydroxyvitamin D (25OHD) concentrations have been associated with dementia. The association with mild cognitive impairment (MCI) has not yet been explored. Our aim was to examine the association between vitamin D status and MCI status amongst older community-dwellers with subjective memory complaint. METHODS: Ninety-five non-demented Caucasian community-dwellers with subjective memory complaint (mean, 71.1 ± 6.4 years; 54.7% women) included in the Gait and Alzheimer Interaction Tracking (GAIT) study were categorized into two groups according to Winblad et al. consensus criteria [i.e., subjects with MCI or cognitively healthy individuals (CHI)]. Serum 25OHD concentration was divided into quartiles, the fourth quartile corresponding to the highest 25OHD concentration. The cross-sectional associations between 25OHD concentrations and MCI were modeled using logistic regressions. Age, gender, body mass index, number of comorbidities, education level, Mini-Mental State Examination score, Frontal Assessment Battery score, Geriatric Depression Scale score, creatinine clearance, and season tested were considered as potential confounders. RESULTS: Compared to CHI, patients with MCI (n = 43; mean, 71.4 ± 5.6 years; 34.9% women) had lower mean serum 25OHD concentrations (P = 0.006) and belonged more often to the lower quartiles compared to the highest quartile (P = 0.03). Increased serum 25OHD concentration was associated with a lower risk of MCI [adjusted odds ratio (OR) = 0.96, P = 0.002]. Accordingly, lower quartiles of 25OHD were positively associated with MCI whilst using the highest quartile as reference (adjusted OR = 25.46, P = 0.002 for the first quartile; adjusted OR = 6.89, P = 0.03 for the second quartile; and adjusted OR = 10.29, P = 0.02 for the third quartile). CONCLUSIONS: Low 25OHD concentrations were associated with MCI status in older non-demented community-dwellers with subjective memory complaint.