Higher caffeine and urate levels may protect against Parkinson's

Two purines — caffeine and urate — have been associated with a reduced risk of Parkinson’s disease (PD) in multiple study groups and populations. A study published in the Journal of Parkinson’s Disease now shows that lower levels of caffeine consumption and lower blood urate are inversely associated with PD, strengthening the links between caffeine intake and urate levels and the neurodegenerative disorder.

“Both caffeine and urate possess neuroprotective properties via adenosine receptor antagonist and antioxidant actions, respectively,” explained lead investigator Dr Rachit Bakshi, from Massachusetts General Hospital and Harvard Medical School. “They both have protective properties in animal models of PD, raising the possibility of their disease-slowing potential.”

Dr Bakshi and colleagues investigated whether these reduced risk factors are associated with PD in participants in the Harvard Biomarkers Study (HBS), which is a longitudinal study designed to accelerate the discovery and validation of molecular diagnostic and progression markers of early-stage PD. Investigators conducted a cross-sectional, case-control study of 369 individuals with idiopathic PD and 197 healthy controls from the full HBS cohort. Urate was measured in plasma samples collected at each participant’s initial HBS visit. Caffeine intake was also assessed at each participant’s initial HBS visit using a semi-quantitative questionnaire, which queried participants’ usual consumption of caffeinated and decaffeinated coffee, tea and soft drinks during the previous 12 months.

Caffeine intake was lower in idiopathic PD patients compared to healthy controls. The odds of having PD decreased significantly with increasing caffeine consumption in a concentration-dependent manner across quintiles of caffeine consumption, adjusting for age, sex, BMI and plasma urate. Compared with the lowest caffeine consumption quintile, the prevalence of PD was over 70% lower in the highest quintile. A strong inverse association was also observed with plasma urate levels both in males and females. An equally large association between urate and PD risk was observed among women, in contrast with most prior studies of the association between urate and idiopathic PD stratified by sex. These findings support the generalisability of discoveries made with this cohort, which is well suited for deep analysis of relationships between dietary factors, genes, established and novel biomarkers, and clinical phenotypes of PD.

The investigators caution that a recent large clinical trial of a urate-elevating treatment failed to demonstrate a benefit for people with PD over months to years. Thus, even though the current study strengthens the link between PD and lower urate levels, strategies to raise them may be harmful and cannot be recommended. Meanwhile, caffeine has yet to be rigorously studied in a long-term PD trial; therefore, increasing one’s caffeine intake cannot be recommended. Nevertheless, people who currently enjoy caffeine in coffee or tea may take additional pleasure in knowing of its potentially therapeutic potential.

“Identifying factors that are linked to lower likelihood of PD, such as caffeine consumption, offer a unique opportunity to understand … [and] possibly to slow the disease,” concluded Dr Bakshi.

Image credit: ©Africa Studio/Dollar Photo Club

Please follow us and share on Twitter and Facebook. You can also subscribe for FREE to our weekly newsletters and bimonthly magazine.