Vitamin D deficiency is associated with cognitive decline: results from the InCHIANTI study
Key Finding
Severe vitamin D deficiency was associated with 60% greater risk of substantial cognitive decline over 6 years.
Plain-English Summary
This prospational study from the InCHIANTI cohort followed 858 older adults over 6 years to examine the relationship between vitamin D levels and cognitive decline. Participants underwent cognitive testing and vitamin D measurement at baseline and follow-up.
Individuals with severe vitamin D deficiency (below 25 nmol/L) had a 60% greater risk of substantial cognitive decline compared to those with sufficient levels. The association remained significant after controlling for age, education, physical activity, and other confounders.
Vitamin D receptors are found throughout the brain, particularly in areas involved in memory and learning. Vitamin D supports neuroprotection through anti-inflammatory effects, antioxidant defense, and regulation of calcium signalling. Given widespread deficiency, especially in northern latitudes, vitamin D optimization may be a simple and important strategy for supporting long-term cognitive health.