Low levels of vitamin D are associated with an increased risk of incident hospital-diagnosed delirium, with genetic evidence indicating a causal association. The findings were published in the Journal of the American Geriatrics Society.
Researchers conducted a community-based cohort study of adults across 22 cities in the UK. The prospective cohort analysis included 351,320 UK Biobank participants who reached the age of 60 years before the end of the inpatient follow-up period.
Three thousand six hundred and thirty-four (1.0%) participants had a diagnosis of incident delirium in hospital admissions data. Compared with sufficient vitamin D levels (>50 nmol/L), vitamin D deficiency (<25 nmol/L) at baseline was associated with an increased risk for incident delirium (HR, 2.49; 95% CI, 2.25-2.76). Furthermore, individuals with vitamin D insufficiency (25-50 nmol/L) also had an increased risk of delirium (HR, 1.38; 95% CI, 1.28-1.49). The associations between vitamin D levels and delirium remained significant even after the exclusion of hospital-diagnosed bone fractures, chronic kidney disease and liver disease.
A genetic analysis showed that individuals carrying more vitamin D-increasing genetic variants had a lower likelihood of being diagnosed with incident delirium.
"Our results suggest that older adults should be routinely screened for vitamin D levels during general practitioner visits to help ensure they are at sufficient levels in the event that they require hospitalization where risk for delirium increases considerably," the authors said.
