Oslo Sports Trauma Research Center

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Information about project titled 'Neurofilament light and tau in serum after head impact exposure in football'

Neurofilament light and tau in serum after head impact exposure in football

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Project status: Published
Project manager: Stian Bahr Sandmo
Supervisor(s): Roald Bahr, Thor Einar Andersen
Coworker(s): Truls Straume Næsheim, Peter Filipcik, Jozef Hanes, Martin Cente


Background: The link between head impact exposure in football and potential neurological sequelae is poorly understood. Blood-based biomarkers can provide valuable information in traumatic brain injuries, reflecting e.g. axonal damage in response to neuronal injury.

Aim: To investigate if repetitive headers or accidental head impacts in football cause structural damage to the brain, detected as an increase in serum concentrations of neurofilament light (NfL) or tau proteins.

Methods: Baseline NfL and tau were measured in Norwegian professional football players in pre‑season. Then, the effect of different short-term exposures was assessed by measuring biomarker levels after three conditions: (1) high‑intensity exercise, (2) repetitive headers, and (3) head‑impact incidents in a match. In addition, the effect of long-term head impact exposure was assessed by comparing two groups with relative differences in previous concussions and headers at baseline (low vs. high levels).

Results: We analyzed 354 samples and observed no effects on serum NfL after exposure from neither of the three short-term conditions. Tau levels rose in response to high-intensity exercise and repetitive headers, but not after accidental head-impact incidents; the highest absolute values were seen 1 h after high-intensity exercise. We did not detect any long-term effects on serum NfL or tau concentrations from previous concussions and headers.

Conclusion: NfL and tau in serum were unaffected by head impacts in football, after both short‑term and long-term exposure. Importantly, tau levels seem to rise in response to exercise, emphasizing the need for appropriate control groups in future studies. Our findings highlight important characteristics and limitations for using NfL and tau as biomarkers in sports.