@cremieuxrecueil Your "quick-and-dirty" Mendelian randomization (MR) is already outmatched

Well SupportedGenetically determined low vitamin D levels increase dementia risk by 54%.

Well SupportedVitamin D supplementation (800 IU daily for one year) improved memory, attention, and IQ in individuals with mild cognitive impairment.

Well SupportedVitamin D directly regulates neuronal inflammation, amyloid clearance, neurotrophic factors, and oxidative stress pathways by controlling gene expression.

Well SupportedEach 10 nmol/L increase in vitamin D is associated with a small decrease in white matter hyperintensities, suggesting brain protection.

Not Supported