New research published in Neurology has demonstrated an inverse relationship between caffeine consumption and the risk of Parkinson’s disease. Building on previous research that supports caffeine blocking the adenosine 2A receptor, this prospective study quantified biomarker caffeine intake years before PD onset and assessed which caffeine metabolites are related to Parkinson’s.

This large, population-based study analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, which was designed to assess the relationship between nutrition and disease. A global subset of patients from EPIC (EPIC4PD) included individuals from Italy, Spain, UK, Netherlands, Germany, and Sweden.

The study consisted of two parts—the prospective EPIC4PD study and a nested case-control study to examine the role of caffeine metabolites in Parkinson’s risk. Coffee consumption information was collected via a self-reported 24-hour diet recall questionnaire and converted to mL/day. Caffeine metabolites were measured by plasma samples taken an average of eight years before Parkinson’s diagnosis.

The EPIC4PD cohort was followed for a median of 13.1 years and included 593 individuals with Parkinson’s disease (diagnosed a median of 8.3 years after recruitment). Ninety-three percent of the study population reported drinking coffee. The protective effects of caffeine were exposure dependent—in the highest quartile of coffee consumers vs non-consumers, the hazard ratio for developing Parkinson’s was 0.63 (95% CI 0.46–0.88; P=0.003). There was no association between decaffeinated coffee consumption and risk of Parkinson’s.

The nested case-control study included 351 patients with incident Parkinson’s and 351 age- and sex-matched controls. Self-reported coffee consumption was positively associated with caffeine metabolite levels. Caffeine and three of its metabolites, paraxanthine, theophylline, and 1-methyluric acid, had an inverse relationship with Parkinson’s risk (odds ratios 0.80 [0.67–0.95], 0.82 [0.69–0.96], 0.78 [0.65–0.93], and 0.84 [0.72–0.98], respectively). Various other metabolites did not demonstrate statistically significant associations with Parkinson’s risk.

The authors note that previous research has demonstrated a modest effect of caffeine on Parkinson’s symptoms, but given that the current study used data from participants before they were diagnosed, they posit that consumption during the prodromal phase of disease may offer higher neuroprotective effects. In fact, another recent study that examined the effects of caffeine consumption on dopamine function found no benefits in patients who had already been diagnosed with Parkinson’s.

” … Our study validated the protective effect of caffeine on PD risk in a large prospective cohort and further confirmed the etiologic role of caffeine using biosamples before PD diagnosis. Additional research on the protective action of caffeine and its main metabolites could build on knowledge gained from this study and provide additional insights into the etiology and potential prevention of PD,” conclude the study authors.

Read the study

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