Soccer Heading May Be Riskier for Female Players

Sex-based differences in susceptibility to brain injury may lead to better understanding of biologic variances


Compared with their male counterparts, female soccer players exhibit more extensive changes to brain tissue after repetitive heading of the soccer ball, according to a new Radiology study.

Soccer is the most popular competitive sport in the world, and female participation in the sport is on the rise. The Fédération Internationale de Football Association (FIFA) 2014 Women’s Football Survey reported more than 30 million female soccer players worldwide.

Heading is a key component of the game. Heading-related impacts have been associated with abnormalities in the brain’s white matter that are similar to those seen in patients with traumatic brain injury. Cumulative heading over a one-year period has been associated with cognitive dysfunction and microstructural changes to the brain’s white matter. Repetitive head injury in athletes has been associated with cognitive decline and behavioral changes.

“In general, men do a lot more heading than women, but we wanted to specifically examine if men and women fare similarly or differently with a similar amount of exposure to repeated impacts to the head,” said the study’s lead author, Michael L. Lipton, MD, PhD, professor of radiology at the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine and medical director of MRI at Montefiore Medical Center in New York City.

Dr. Lipton and colleagues used diffusion tensor imaging (DTI) to assess microscopic changes in the brain’s white matter in 98 amateur soccer players – 49 men and 49 women – with an average age of 25.8 years. All participants had many years of soccer and heading exposure, including 12 months of frequent heading exposure leading up to the study (median headers: 487 per year for the men and 469 per year for the women). Participants had no significant differences in demographic factors.

White Matter Microstructure Decreases Indicate Inflammation or Neuron Loss

Researchers compared white matter fractional anisotropy (FA) values among the male and female soccer players. The analysis revealed that while both men and women experienced lower FA values related to more repetitive heading, women exhibited lower FA levels across a much larger volume of brain tissue.

“In both groups, this effect we see in the brain’s white matter increased with greater amounts of heading,” Dr. Lipton said. “But women exhibit about five times as much microstructural abnormality as men when they have similar amounts of heading exposure.”

Among men, three regions were identified in which a greater number of heading events was significantly associated with lower FA including the genu and splenium of the corpus callosum and the pons. In men, there was only one location, the left temporal white matter, in which a greater exposure to heading was associated with significantly higher FA.

In women, eight regions were identified in which greater heading exposure showed a significant association with lower FA including the genu of the corpus callosum; left occipital, right parietal and right orbitofrontal white matter; left superior longitudinal fasciculus; right cingulum; and right cerebral peduncle.

Overall, an association between greater heading exposure and FA was detected across 2,121 mm3 of white matter in women, compared with 408 mm3 in men.

“The important message from these findings is that there are individuals who are going to be more sensitive to heading than others,” Dr. Lipton said. “Our study provides preliminary support that women are more sensitive to these types of head impacts at the level of brain tissue microstructure.”

Dr. Lipton said that more research is needed to confirm findings and further characterize gender differences in vulnerability to brain injury due to heading.

“We don’t have enough information yet to establish guidelines to protect the players,” Dr. Lipton said. “But by understanding these relationships – how different people have different levels of sensitivity to heading – we can get to the point of determining the need for gender-specific recommendations for safer soccer play.”

Three-dimensional semitransparent images of the Johns Hopkins University template brain oriented facing the right hemisphere in, A, male, and, B, female soccer players demonstrate that lower FA is associated with heading more extensively in women than in men. Fewer regions of significant association of FA with heading are detected in men than in women. C, Image shows that significant differences in association of heading and FA between men and women are predominantly co-located with areas where women, but not men, show significant association of heading and FA.

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