New research has found that coffee consumers had a lower risk of developing Parkinson’s disease compared to individuals not drinking coffee. Adjusting for smoking and alcohol consumption did not change these findings. The research was published in Neurology.
Parkinson’s disease is a progressive neurodegenerative disorder that primarily affects movement control. It occurs due to the loss of dopamine-producing neurons in a specific area of the brain called the substantia nigra. Common symptoms include tremors, stiffness, slowed movement, and balance problems, which gradually worsen over time. In addition to motor symptoms, individuals with Parkinson’s may also experience non-motor symptoms such as sleep disturbances, depression, and cognitive impairment.
Factors leading to the development of Parkinson’s disease are currently not fully understood. However, studies have indicated that individuals who frequently engage in activities involving impacts to the head, such as boxing and other contact sports, have a higher likelihood of developing the disease. Studies have also found reduced levels of caffeine and its major metabolites, paraxanthine and theophylline, in individuals suffering from Parkinson’s disease.
Following up on these findings, study author Yujia Zhao and her colleagues note that coffee is the most widely consumed psychoactive beverage in the world. It also contains significant amounts of caffeine. With this in mind, they set out to investigate the relationship between coffee consumption and the risk of developing Parkinson’s disease using longitudinal data.
These researchers noted that data collected in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study contains participants’ answers about their coffee consumption. The EPIC is an ongoing longitudinal study involving over half a million individuals from 10 European countries recruited between 1992 and 2000. The EPIC study aims to explore the relationship between nutrition and noncommunicable diseases (diseases that are considered noncontagious). At the start of the study, participants were between 35 and 70 years of age.
The study authors analyzed data from a substudy of EPIC that focused on Parkinson’s disease called EPIC4PD. This subgroup of participants included 184,024 individuals from Sweden, the United Kingdom, the Netherlands, Germany, Spain, and Italy who participated in the study for an average of 13 years.
These individuals completed a dietary questionnaire that included questions on coffee consumption, as well as smoking, alcohol consumption, education level, and physical activity. Parkinson’s disease data came from participants’ medical records and were validated by experts in movement disorders. A small portion of study participants provided blood samples for assessing the levels of caffeine metabolites (substances that are created when the body processes caffeine) in the blood plasma.
Results showed that, of all the participants included in the study, 308 men and 285 women developed Parkinson’s disease (less than 1%). Ninety-three percent of study participants reported drinking coffee. Coffee consumption was highest among participants from the Netherlands (around 500 milliliters per day) and lowest in Italy and Spain (around 100 milliliters per day). Those consuming the most coffee were more often men, smokers, younger, and more prone to consuming alcohol.
The 25% of participants with the highest coffee intake were nearly 40% less likely to develop Parkinson’s disease compared to participants who did not drink coffee at all. When all coffee consumers were compared to participants not drinking coffee, the risk reduction ranged between 63% and 5% depending on the country. The association between Parkinson’s disease and coffee consumption was approximately equally strong in men and women, but seemed to be slightly stronger among people who never smoked.
“This study demonstrated an inverse association of caffeinated coffee consumption with the risk of PD [Parkinson’s disease] in one of the largest longitudinal cohorts worldwide with more than 20 years of follow-up. The neuroprotective effects of coffee were exposure dependent, and individuals in the highest coffee consumption group had nearly 40% lower risk of PD compared with non-consumers,” the study authors concluded.
“This observation was strengthened with a comprehensive evaluation of prospectively measured plasma caffeine and its metabolites. These analyses showed strong inverse associations for caffeine and its major metabolites with the risk of PD.”
The study sheds light on the links between coffee consumption and Parkinson’s disease. However, it should be noted that the study design does not allow any definitive cause-and-effect inferences to be drawn from the data. Additionally, coffee consumption was assessed through self-report questionnaires, leaving room for reporting bias.
The paper, “Association of Coffee Consumption and Prediagnostic Caffeine Metabolites With Incident Parkinson Disease in a Population-Based Cohort,” was authored by Yujia Zhao, Yunjia Lai, Hilde Konijnenberg, José María Huerta, Ana Vinagre-Aragon, Jara Anna Sabin, Johnni Hansen, Dafina Petrova, Carlotta Sacerdote, Raul Zamora-Ros, Valeria Pala, Alicia K. Heath, Salvatore Panico, Marcela Guevara, Giovanna Masala, Christina M. Lill, Gary W. Miller, Susan Peters, and Roel Vermeulen.