Soccer is the most popular competitive sport in the world, and female participation in the sport is on the rise, but a new study published in the journal Radiology shows that a particular action — heading the ball — may be riskier for females than their male counterparts as female soccer players exhibit more extensive changes to brain tissue after repetitive ‘heading’ of the soccer ball.
Michael L. Lipton, professor of radiology at the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine, and colleagues conducted the study to examine the role of sex in abnormal white matter microstructure after soccer heading as identified by using the diffusion-tensor imaging (DTI) metric fractional anisotropy (FA).
The heading is a key component of soccer, in which players field the ball with their heads. 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.
Long-term consequences of repeated exposure to heading is an area of concern because a repetitive head injury in athletes has been associated with cognitive decline and behavioral changes.
The research team used diffusion tensor imaging (DTI), an advanced MRI technique, 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.
DTI produces a measurement, called fractional anisotropy (FA), which characterizes the movement of water molecules in the brain. In healthy white matter, the direction of water movement is fairly uniform and measures high in FA. When water movement is more random, FA values decrease.
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.
- 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 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.
- 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 seven of the eight regions identified in women, the association between heading and FA was stronger in women than in men.
- There was no significant difference of heading with FA between the sexes for any region in which heading was associated with FA among men.
- 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.
“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.”
“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.”
For more information follow the link: https://doi.org/10.1148/radiol.2018180217