Amateur Soccer Heading and Acute Elevations in Blood-Based p-Tau217 and S100B

Importance: Former professional soccer players have increased risk of neurodegenerative disease, potentially due to cumulative exposure to repetitive head impacts such as heading. However, the acute effects of heading on neural integrity remain unclear. Objective: To assess the acute association of real-life heading with blood biomarkers of neural damage before and after soccer matches. Design, Setting, and Participants: In this prospective population-based case-control study, soccer players participated in organized matches (August-December 2024). Blood samples were collected prematch and immediately and delayed postmatch (20 m; 80 players [26%] with exposure to a single high-impact header; 65 players [22%] with exposure to multiple high-impact headers). Players exposed to heading showed significantly greater immediate postmatch increases in S100B concentration (n = 299, P = .03; Cohen d = 0.29) compared with unexposed players. Exposure to more headers was associated with greater increases in S100B (n = 299, P = .02; Cohen d = 0.07 per header) and p-tau217 concentration (n = 296, P = .01; Cohen d = 0.09 per header). High-impact headers were also associated with greater increases in p-tau217 (n = 148, P = .03; Cohen d = 0.40) and S100B concentration (n = 149, P = .02; Cohen d = 0.43) compared with no exposure. Observed biomarker elevations normalized within 24 to 48 hours. No other significant associations were found. Results were robust to sensitivity analysis adjusting for blood volume. Conclusion and Relevance: Findings of this case-control study show that soccer heading was associated with acute increases in blood biomarkers of neural damage, including dose-response relationships. These findings suggest that amateur-level heading may acutely affect neural integrity.