According to the International Federation of Association Football (FIFA), about 30 million women and girls play soccer worldwide. Soccer – or “football” as it’s known in most parts of the world – is one of the most widely played international sports. From a young age, kids around the world are learning how to play the game without using their hands. One of the consequences of the sport is the frequent “heading” of the ball, where a player redirects the flying ball using their head. This has led to a multitude of studies on the effects of this repeated head contact in soccer players.
A new study from researchers at Albert Einstein College of Medicine, part of Montefiore Medical Center, has found that women’s brains are significantly more vulnerable to injury from repeated soccer heading compared to men’s brains. The study – published in Radiology – found that regions of damaged brain tissue were five times more extensive in female soccer players than males.
“Researchers and clinicians have long noticed that women fare worse following head injury than men, but some have said that’s only because women are more willing to report symptoms,” says leader of the study Michael L. Lipton, M.D., Ph.D., professor of radiology and of psychiatry and behavioral sciences at Einstein and medical director of MRI Services at Montefiore. “Based on our study, which measured objective changes in brain tissue rather than self-reported symptoms, women do seem more likely than men to suffer brain trauma from heading soccer balls.”
The study involved performing diffusion tensor imaging (DTI) on 49 male and 49 female amateur soccer players enrolled as participants. Both groups reported a similar number of headings over the previous year at around 500. DTI is a form of MRI that detects subtle brain damage through measuring the direction of the diffusion of water in white matter, which is the deep brain tissue that coordinates communication between brain regions. The diffusion of water was measured on a zero-to-one scale called fractional anisotropy (FA), where a low score indicates structural damage to the brain.
The results of the researchers’ assessment showed that women soccer players had a much higher volume of damaged white matter, with eight brain regions where greater levels of heading were associated with lower FA compared to only three regions in men. The reasons for this difference are not currently known, but researchers believe it may be due to differences in neck strength, and that sex hormones or genetics may play a role.
Although the changes in FA were subclinical – in that they didn’t produce any clinical findings such as altered thinking ability – these results are still a cause for concern. “In various brain injuries, including chronic traumatic encephalopathy, subclinical pathology develops before we can detect brain damage that affects function,” says Dr. Lipton. “So before serious dysfunction occurs, it’s wise to identify risk factors for cumulative brain injury – such as heading if you’re female – so that people can act to prevent further damage and maximize recovery.”
One of the solutions to this problem may lie in soccer organizations coming up with preventative measures to limit the number of headers individuals are allowed – especially at younger ages. Although banning heading altogether is rather unrealistic, the researchers believe there are appropriate steps that can be taken. In the meantime, much more research needs to be done to better determine the mechanics and physiology behind these findings.