No neurochemical evidence for brain injury caused by heading in soccer.

Background: The possible injurious effect to the brain of heading in soccer is a matter of discussion.

Objective: To determine whether standardised headings in soccer are associated with increased levels of biochemical markers for neuronal injury in cerebrospinal fluid (CSF) and serum.

Methods: 23 male amateur soccer players took part in a heading training session involving heading a ball kicked from a distance of 30 m at least 10 m forward. Ten players performed 10 and 13 players performed 20 approved headings. The players underwent lumbar puncture and serum sampling 7-10 days after the headings. The study also included 10 healthy male non-athletic control subjects. CSF was analysed for neurofilament light protein, total tau, glial fibrillary acidic protein, S-100B and albumin concentrations. Serum was analysed for S-100B and albumin.

Results: None of the biomarker levels were abnormal and there were no significant differences between any of the three groups, except for a slightly increased CSF S-100B concentration in controls compared with headers. Biomarker levels did not correlate with the number of headings performed.

Conclusion: Repeated low-severity head impacts due to heading in soccer are not associated with any neurochemical signs of injury to the brain.