Older adults with low levels of folate (vitamin B9) may be at heightened risk of dementia and death from any cause, according to a study published in the journal Evidence Based Mental Health.

The study, which drew on the medical records of more than 27,000 people, found that the folate deficient were 68% more likely to be diagnosed with dementia and nearly 3 times as likely to die from any cause. 

While previous studies have suggested that that folate deficiency affects cognition and nerve signalling in the brain, they have been on a small scale and have produced mixed results. 

These results, however, draw on a large national sample of older adults and considers the potential role of reverse causation. 

The folate deficient were more than double as likely to be diagnosed with dementia

The participants of the study were aged between 60 and 75 and had no pre-existing dementia for at least 10 years before blood folate checks began in 2013. Their records were then monitored for a diagnosis of dementia or death up to the end of 2017.

Around 13% of participants were folate deficient, and among these people the incident of dementia was estimated at 7.96 per 10,000 person years, while death from any cause was estimated at 19.20 per 10,000 person years. 

This compares with an estimated dementia incidence of 4.24 and of death from any cause of 5.36 per 10,000 person years among those who weren’t folate deficient.

After accounting for potentially influential factors, the folate deficient were more than double as likely to be diagnosed with dementia and nearly 3 times as likely to die from any cause. 

Older adults should be routinely screened for folate deficiency

While the researchers note that the study is observational and cannot establish a cause, they say it is possible that folate deficiency might affect homocysteine levels and therefore the vascular risk of dementia.

It is also possible that a deficiency in vitamin B9 could compromise DNA repair of neurons, making them vulnerable to oxidative damage, which in turn might speed up brain cell ageing and damage, they explain.

For this reason, the researchers say that older adults should be routinely screened for folate deficiency as a preventative measure for dementia and death.