A recent study published by The Journal of the American Medical Association's (JAMA) Network Open describes a connection between playing American football and an increased risk of developing Parkinson’s disease (PD) or a related parkinsonism (i.e., disorders that cause symptoms similar to PD, such as tremor and slowness).

This research was conducted by a team at Boston University, using data collected by Fox Insight — an online study sponsored by The Michael J. Fox Foundation for Parkinson’s Research (MJFF) that gathers data from a large cohort of people with PD and age-matched control volunteers. For this research, the team analyzed survey responses from 1,875 Fox Insight study participants.

That sample size makes this research the largest to date to investigate the relationship between playing football and having a diagnosis of Parkinson’s disease. The analysis revealed that participants with a history of playing organized tackle (American) football had a 61 percent increased chance of Parkinson’s or parkinsonism. The risk increased among all football players, regardless of the duration or level, but was higher in those who played for more time overall and at a higher level (i.e., college or professional vs. youth or high school).

The takeaway: This is a link, but not a definite cause

It’s worth noting that while the study identifies an association between playing football and a PD or parkinsonism diagnosis, it doesn’t establish a cause-effect relationship. The bottom line? Playing football will not necessarily lead to Parkinson’s. But it does suggest that certain factors associated with football may increase the risk of developing the disease. While we don’t know for certain, these risks could be due to repetitive head injuries (which some research has linked to PD previously), exposure to pesticides on playing fields (pesticides also have known links to PD) or other, yet unidentified, factors.

It's also important to highlight the limitations of the study, including relying on people to self-report their diagnosis (i.e., a diagnosis not confirmed by a doctor) and to accurately remember when and for how long they played football. Respondents also were primarily white and men, which means these results may not be fully representative of the broad population of people living with Parkinson’s.

If I played football, what does this mean for me?

This study presents noteworthy findings, yet more research is necessary to fully understand the causes of and contributors to PD, including what role football might play. However, these results build on our understanding of what behaviors or environmental factors could contribute to someone being “at risk” for disease.

Movement Disorder Specialist and MJFF’s Senior Vice President of Medical Communications Rachel Dolhun, MD, DipABLM, says, “Studies like this contribute to a growing body of evidence illuminating risks associated with Parkinson’s. And this type of information allows us to learn more about how and why Parkinson’s comes on, how best to treat it, and how to, one day, hopefully prevent it. These research results do not mean that if you play or played football you’re destined to develop Parkinson’s. But they do highlight a link. And knowing about this connection can give people, including younger adults, the power to make decisions and take steps to care for their brains as best as possible all throughout life.”

Participation in research initiatives like Fox Insight or the Foundation’s Parkinson’s Progression Markers Initiative (PPMI) is critical in advancing science. Through the contributions of research volunteers, this study's findings are adding to our evolving understanding of Parkinson's disease, guiding our search for preventive measures and effective treatments.