Vitamin D and dementia

Vitamin D deficiency and insufficiency among US adults: prevalence, predictors and clinical implications

https://www.cambridge.org/core/journa...

(University of Michigan School of Medicine, 2018)

Vitamin D deficiency (VDD) and insufficiency (VDI) are increasing at a global level

Serum 25-hydroxyvitamin D (25(OH)D) measurements were collected from 26,010 adults

(National Health and Nutrition Examination Survey, NHANES)

VDD, less than 50 nmol/l (20 ng ml)

VDI, 50 to 75 nmol/l (20 – 25 ng ml)

Prevalence

VDD, 28·9%

VDI, 41·4 %

Adults who were black, less educated, poor, obese, physically inactive and infrequent milk consumers

Obese adults, 3·09 times higher prevalence of VDD

(1·80 times higher prevalence of VDI)

Physically inactive adults, 2·00 times VDD

(1·36 times higher prevalence of VDI)

Vitamin D status in the United States, 2011–2014

https://academic.oup.com/ajcn/article...

Persons with higher vitamin D dietary intake or who used supplements had lower prevalences of at risk of deficiency or inadequacy.

Vitamin D deficiency 2.0: an update on the current status worldwide

https://www.nature.com/articles/s4143...

Most studies did not meet the basic requirements of a nutrient intervention study

~40% of Europeans are vitamin D deficient,

and 13% are severely deficient

Vitamin D deficiency

(serum 25-hydroxyvitamin D less than 50 nmol/L or 20 ng/ml),

associated with unfavourable skeletal outcomes, including fractures and bone loss

Level of more than 50 nmol/L or 20 ng/ml is, therefore, the primary treatment goal

Severe vitamin D deficiency, below less than 30 nmol/L (or 12 ng/ml),

dramatically increases the risk of excess mortality, infections, and many other diseases,

and should be avoided whenever possible.

Given its rare side effects and its relatively wide safety margin, it may be an important, inexpensive, and safe adjuvant therapy for many diseases,

but future large and well-designed studies should evaluate this further.

Vitamin D supplementation and incident dementia: Effects of sex, APOE, and baseline cognitive status

https://alz-journals.onlinelibrary.wi...

Vitamin D exposure was associated with 40% lower dementia incidence versus no exposure.

(Prospective, n = 12,388)

Low vitamin D serum levels as risk factor of Alzheimer’s disease: a systematic review and meta-analysis

https://ejnpn.springeropen.com/articl...

Serum vitamin D levels, related to cognitive dysfunctions, e.g. dementia, including Alzheimer’s disease

Past studies vary in results on whether vitamin D levels correlated with the development of AD.

Meta-analysis, up to December 2022

AD, 75% of dementias

Results

6 studies, n = 10,884

Vitamin D receptors throughout the brain

Patients, vitamin D serum levels (less than 25 ng/ml),

had an increased risk of developing AD,

compared to more than 25 ng/ml

HR: 1.59

Severe deficiency (less than 10 ng/ml) having the strongest association,

compared to moderate vitamin D deficiency (10–20 ng/ml).

Vitamin D may promote the clearing of amyloid plaques

Vitamin D also prevents cognitive dysfunction via neuroprotection, neurotrophy, neurotransmission, and neuroplasticity

Potential to prevent neuroinflammation, inhibits proinflammatory cytokines

https://www.gov.uk/government/publica...

In the UK during autumn and winter,

everyone is advised to take a supplement containing,

10 micrograms (400 international units) of vitamin D a day
https://ods.od.nih.gov/factsheets/Vit...