In a study published in the journal Radiology, the researchers responsible for a recent study illustrating the concussion risks of heading a soccer ball have now found that women are much more vulnerable to head injuries.
The popularity of soccer among women and girls has grown considerably in recent years. The sport’s governing body, the Fédération Internationale de Football Association (FIFA), reports that more than 30 million females play the game worldwide.
The vulnerability of females to head trauma has long been reported, but study leader Michael Lipton, of the Albert Einstein College of Medicine in New York’s the Bronx, US, notes that some believe this is because women are more willing to report symptoms.
The new study refutes this point by rejecting a self-report model in favour of an advanced form of medical resonance imaging (MRI) called diffusion tensor imaging (DTI). DTI detects damage to the brain’s white matter by measuring the direction of water movement in the organ, producing a result called fractional anisotropy (FA).
The more uniform the water diffusion, the higher the FA value, which indicates stronger integrity of the brain tissue. Conversely, Lipton explains, “a decline in FA is an indicator of changes in the white matter microstructure that may be indicative of inflammation or loss of neurons”.
The researchers gathered 49 active amateur football players from each gender, with both groups reporting a similar incidence of heading over the previous year – 487 for the men and 469 for the women. Assessing the FA values in the players showed the volume of damaged white matter was five times greater in women than men.
Specific regions of the brain in which frequent heading resulted in lower FA were also pinpointed, with eight identified in women compared to three in men.
Factors including differences in neck strength, genetics and sex hormones have been suggested as possible causes for women’s sensitivity to head impacts. Lipton, however, urges a degree of caution and calls for further study to better characterise the gender differences in vulnerability to head trauma before action is taken.
“We don’t have enough information yet to establish guidelines to protect the players,” he says.
“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.”
Lipton, who has studied the cumulative effects of brain injury for more than a decade, also believes at this stage that mooted bans to heading, which are already in force in junior football in the United States, are not necessarily the answer.
“We have carried out several studies showing that most players seem to tolerate some level of heading,” he explains.
“Rather than ban heading altogether – which probably isn’t realistic – we’d like to get a better handle on how many headers will get players into trouble. What is important about this study is that men and women may need to be looked at differently.”