A low blood level of folate may be linked to an increase
Low levels of folate (vitamin B9) in the blood may be linked to an increased risk of dementia and death from any cause in older people, suggests research published online in the journal Evidence-Based Mental Health.
Levels should be regularly monitored and deficiencies corrected in old age, especially since blood levels of folate tend to decline with age, with up to 1 in 5 older people estimated to be folate deficient, according to Researchers.
Evidence to date suggests that folate deficiency affects cognition and nerve signaling in the brain, making it a possible risk factor for later dementia.
But the few studies that have looked at this have included small numbers of participants and produced mixed results.
And because of the time it takes for dementia to develop, it was difficult to rule out reverse causation, whereby folate deficiency could be a consequence of preclinical dementia rather than its cause, they add.
They therefore wanted to see whether serum folate deficiency could be linked to the risks of incident dementia and death from any cause in a large national sample of older adults, and to include the potential role of reverse causation.
They relied on the medical records of 27,188 people served by a national healthcare provider in Israel. All of the participants were between the ages of 60 and 75 and had not had pre-existing dementia for at least 10 years before blood folate testing began in 2013.
Their records were watched for a diagnosis of dementia or death until the end of 2017.
Some 3,418 participants (just under 13%) had folate deficiency, defined as levels below 4.4 ng/ml. Folate deficiency was associated with a significantly increased risk of dementia and death from any cause.
Among those with folate deficiency, the incidence of dementia was estimated at 7.96 per 10,000 person-years, while deaths from all causes were estimated at 19.20 per 10,000 person-years.
This compares with an estimated incidence of dementia of 4.24 and death from all causes of 5.36 per 10,000 person-years in those who were not folate deficient.
In percentage terms, rates of dementia were almost 3.5% and death from any cause was just under 8% in people with folate deficiency. This compares to rates of dementia of just over 3% and death from all causes of nearly 4% in those who were not folate deficient.
After controlling for potentially influential factors including co-existing diabetes, depression, cognitive decline, vitamin B12 deficiency, smoking and use of folic acid supplements, people with folate deficiency were 68% more likely to be diagnosed with dementia and almost 3 times more likely to die from any cause.
Other analyzes did not significantly weaken the observed associations, but when stratified by the length of the surveillance period, reverse causation could not be ruled out.
This is an observational study and as such cannot establish cause, especially in light of the potential role of reverse causation, the researchers acknowledge.
But it is possible that folate deficiency affects homocysteine levels and therefore the vascular risk of dementia, and/or compromises DNA repair of neurons, making them vulnerable to oxidative damage, which in turn could accelerate aging and brain cell damage, they explain.
They conclude, “Serum folate concentrations may function as a biomarker used to modify risk of dementia and mortality in older adults,” adding that older adults should be routinely screened for folate deficiency.
“Implications for public health policy appear to be to reliably monitor serum folate levels in the elderly and address deficiency for preventive measures and/or as part of implemented therapeutic strategies while regularly reviewing patients’ clinical outcomes,” they write.
Notes for Editors
Research: Serum folate deficiency and the risks of dementia and all-cause mortality: A national study in aging doi 10.1136/ebmental-2021-300309
Newspaper: Evidence-Based Mental Health
Funding: None declared
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Author contact details
Dr Anat Rotstein, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, USA
Tel: +972 522 629 707
Email: [email protected]
Twitter: Anat Rotstein @Arotstein
Professor Stephen Levine, Department of Community Mental Health, University of Haifa, Haifa, Israel.
Tel: +972 524 896 083
Email: [email protected]
About the journal
Evidence-Based Mental Health is one of more than 70 professional journals published by the BMJ. The title is held jointly with the British Psychological Society and the Royal College of Psychiatrists.
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Low blood folate may be linked to increased dementia and risk of death in older adults
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