Vitamin D Deficiency and Its Association with Fatigue and Cognitive Performance in Adults

Abstract

Objective: To assess the prevalence of vitamin D deficiency and its correlation with fatigue and cognitive function in adults attending for tertiary care in a tertiary care hospital.

Methods: A prospective cross sectional study was carried out at Lady Reading hospital from 23 January 2025 to 23 December 2026. 154 adults were consecutively sampled to obtain an enrollment into the study. Vitamin D was analysed in serum samples by chemiluminescence immunoassay. Fatigue Severity Scale was used to measure the severity of fatigue and Montreal Cognitive Assessment questionnaire was used to evaluate cognitive performance. The data were analyzed statistically using Statistical Package for Social Sciences (SPSS) version 26. P values < 0.05 were deemed statistically significant.

Results: Vitamin D deficiency was found in 53.2% and insufficiency was seen in 29.9% of the participants Participants with vitamin D deficiency had significantly higher Fatigue Severity Scale scores and lower Montreal Cognitive Assessment scores than participants with sufficient vitamin D levels. There was significant association of vitamin D deficiency with generalized weakness, daytime tiredness, decreased concentration and cognitive impairment. Pearson correlation analysis showed an inverse correlation between the vitamin D levels and fatigue severity, and a positive relationship was seen between the vitamin D concentration and cognitive performance.

Conclusion: Vitamin D deficiency was common among adults attending a tertiary healthcare facility and was significantly associated with greater fatigue severity and lower cognitive performance. These findings support consideration of vitamin D assessment in adults presenting with fatigue and cognitive complaints. Longitudinal and interventional studies are required to determine causality and the effects of treatment.