Researchers found structural brain differences in some retired professional soccer players compared with people who had no history of repetitive head impacts.
Former players also reported higher levels of anxiety, depression, and difficulties with thinking and decision-making in daily life.
The findings do not show cognitive decline, but they highlight the need for more long-term research and monitoring.
Years of playing professional soccer may leave measurable changes in the brain, even before signs of neurodegenerative disease typically appear.
That's according to new research presented at the Alzheimer's Association International Conference (AAIC) 2026, where scientists shared findings from the largest study to date examining brain health in retired elite professional soccer players.
The researchers were interested in understanding how repeated head impacts over the course of a professional career might affect brain health later in life. While previous research has explored this topic, this study focused specifically on retired players in midlife, offering a snapshot of their brain health before diseases such as Alzheimer's would usually be expected to develop.
Importantly, the researchers did not find meaningful differences in objective thinking and memory tests between former players and people who had not experienced repetitive head impacts. However, they did identify other differences that suggest the topic deserves continued study.
“These findings suggest there may be measurable effects on brain health in former elite soccer players even in mid-life, before clinically apparent neurodegenerative disease would typically emerge,” researcher Caleigh Grace Lynch, M.Sc., said in a news release.
“While we did not find significant differences in objective cognitive testing between the groups, we did observe important differences in symptoms and brain structure.”
How the study was conducted
The study included 142 retired professional soccer players between the ages of 30 and 60. Most were men who had played professionally for at least three years, while 16 were women who competed in the top levels of professional soccer in the United Kingdom. Their results were compared with 56 healthy adults of similar ages who had not played contact sports, served in the military, or experienced repetitive head impacts or neurological conditions.
Participants completed questionnaires about their mental health and daily thinking abilities, along with standardized cognitive testing. Researchers also performed MRI scans on 124 of the former players to examine brain structure and compare those images with scans from members of the control group.
What the findings could mean
Former soccer players reported higher levels of depression and anxiety than the comparison group, along with more self-reported difficulties planning, focusing, solving problems, and managing everyday tasks.
Brain scans also showed lower gray matter volume in several regions involved in memory, attention, decision-making, and emotional regulation. A neuroradiologist reviewing the scans found that about 2% of former players showed brain shrinkage suggestive of neurodegeneration, although researchers said additional investigation is needed to better understand that finding.
At the same time, the players performed similarly to the control group on objective cognitive tests, meaning the study did not find evidence of measurable cognitive decline.
Researchers say these results underscore the importance of following participants over time to learn whether repeated head impacts influence long-term brain health and to help guide future efforts to make sports safer.
“Research like this helps us better understand brain health factors across the lifespan and reinforces the importance of injury prevention and monitoring,” researhcer Maria C. Carrillo, Ph.D., said in the release.
“These findings can help players, physicians and sports organizations better understand the risks of contact sports and how to participate safely.”