Biology of Subjective Cognitive Complaint Amongst Geriatric Patients: Vitamin D Involvement

Background: Insufficiency in vitamin D, a neurosteroid hormone, is associated with cognitive decline in older adults. The impact on the subjective perception of cognitive decline has not yet been examined. The objective of this cross-sectional hospital-based study was to determine whether vitamin D insufficiency was associated with subjective cognitive complaint amongst geriatric patients. Methods: Ninety-nine consecutive Caucasian in- and outpatients recruited in the ’Cognition and LIPophilic vitamins’ (CLIP) study, who had no advanced cognitive disorders (ie, Mini-Mental State Examination score≥20) and who took no vitamin D supplements, were categorized into 2 groups based on vitamin D insufficiency (ie, serum 25-hydroxyvitamin D≥75nmol/L). Subjective cognitive complaint was examined using the Memory Complaint Questionnaire (MAC-Q; score 0-30, best). MAC-Q score<15 out of 30 defined severe cognitive complaint. Age, gender, body mass index, education level, comorbidity burden, functional autonomy, mood, and serum concentrations of parathyroid hormone, calcium, thyroid-stimulating hormone and vitamin B12, and estimated glomerular filtration rate were used as potential confounders. Results: Compared to participants with serum 25OHD>75nmol/L, those with vitamin D insufficiency (n=89) had a lower mean MAC-Q score (14.9±2.9 versus 17.1±1.6, P=0.02) and more often a MAC-Q score<15 (52.8% versus 10.0%, P=0.01). Vitamin D insufficiency was inversely associated with the MAC-Q score (adjusted β=-2.84, P=0.03), and positively associated with severe cognitive complaint (adjusted OR=10.07, P=0.03). Conclusion: Vitamin D insufficiency was associated with subjective cognitive complaint in the studied cohort of geriatric patients.