4th January 2018 – How much caffeine a person has in their blood could provide a simple way to help doctors diagnose Parkinson's disease, according to new research.
The lack of a definitive test to detect Parkinson's is currently one of the main obstacles to developing treatments for the degenerative neurological condition, which affects around 1 in 500 of the UK population.
If the study results can be confirmed, it could result in an easy, early, test for Parkinson's, which can be difficult to diagnose, especially in the initial stages.
Previous studies have shown a link between caffeine and a lower risk of developing Parkinson's disease, but not much is known about how caffeine metabolises within people with the disease.
The small Japanese study published in the medical journal Neurology found that, even if they consumed the same amount of caffeine, people with Parkinson's disease had significantly lower levels of caffeine in their blood than people without the disease.
The study involved 108 people who'd had Parkinson's disease for an average of 6 years, and 31 people of the same age who did not have the disease. The two groups each drank the equivalent of about 2 cups of coffee a day, and their blood was then tested for caffeine and 11 by-products which the body makes as it metabolises caffeine.
The people with Parkinson's disease had significantly lower blood levels of caffeine and lower amounts of 9 of the 11 by-products of caffeine in their blood.
Commenting on the research in a statement, Professor David Dexter, deputy research director at Parkinson's UK, says: "We have known of a link between caffeine and Parkinson's for some time, but up to now this was only related to risk of developing the condition. Here, for the first time, researchers suggest an entirely new association with how caffeine is processed in the body."
However, he cautions: "Due to the lack of participants with other conditions in this study, there is no evidence that this test could distinguish Parkinson's from other neurological conditions. The authors also point out it is unclear if the levels of caffeine in the blood were due to a change in metabolism, or simply because the caffeine was not absorbed in the gut.
"As such, further research is needed before we know if this test holds any promise for improving diagnosis to make it quicker and more accurate."
In an editorial accompanying the study, Dr David Munoz, of the University of Toronto in Canada, noted that the people with Parkinson's participating in the research were all taking medication and it's possible the drugs to treat their Parkinson's could also affect the metabolism of caffeine.
Neurology: Article. Serum caffeine and metabolites are reliable biomarkers of early Parkinson disease
Neurology: Editorial. Caffeine and Parkinson disease. A possible diagnostic and pathogenic breakthrough. David G. Munoz, MD,
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