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.