Longitudinal association between exposure to vitamin D supplementation and incident dementia – A study of dementia‐free older adults

Abstract

Background: In the absence of clear disease-modifying drugs for dementia, modifiable risk factors have been explored to slow disease progression. Vitamin D deficiency is a risk factor, associated with higher risk of dementia. However, the role of vitamin D supplementation has been a subject of debate. Here we explored longitudinal associations between vitamin D supplementation and incident dementia in dementia-free older adults from the National Alzheimer's Coordinating Center (NACC).Method: All participants had normal cognition (NC) or mild cognitive impairment (MCI) at baseline. Exposure to vitamin D supplementation was based on the NACC A4 medication form. Three vitamin D formulations were considered: calcium-vitamin D, cholecalciferol, and ergocalciferol. For the primary analysis, participants with baseline exposure to any supplement were considered D+, while those without any exposure in advance of dementia diagnosis were considered D-. Kaplan-Meier curves were generated to compare ten-year dementia-free survival between D+ and D-groups. Cox proportional hazards models were implemented to assess the risk of dementia across vitamin D exposure groups, adjusted for baseline age, sex, years of education, race, APOE-e4 status, cognitive diagnosis, and depression. To distinguish the associations of various vitamin D formulations with risk of dementia, sensitivity analyses were conducted to independently examine the effect of each formulation (calcium-vitamin D, cholecalciferol, ergocalciferol). Result:The final sample consisted of 2836 D+ (mean age = 72.1; 68.4% female) and 5075 D-participants (mean age = 72; 45.1% female). MCI was more prevalent in D-vs D+ participants (35.7% vs 26.8%; p<0.001). Similarly, depression was more prevalent in D-vs D+ participants (6.9% vs. 4.3%, p<0.001). Across all three vitamin D formulations, exposure was associated with longer dementia-free survival (p<0.001) and lower adjusted hazard ratio (HR) for incident dementia compared to no exposure (calcium-

The effects of the interplay between vitamins, antibiotics, and gut microbiota on the pathogenesis and progression of dementia: A systematic review and meta‐analysis

“…49 Vitamin D deficiency may increase oxidative stress and inflammation, which are linked to dementia. 53 Fat-soluble vitamin D is needed for phosphorus, calcium, bone health, and immunological function. Recent research show vitamin D may be involved in dementia pathogenesis.…”