Women's brains are much more vulnerable than men's to injury from repeated football heading, according to a new study.
Regions of damaged brain tissue were five times more extensive in female football players than in males, suggesting that sex-specific guidelines may be warranted for preventing soccer-related head injuries, showed the findings published online in the journal Radiology.
"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," said study leader Michael Lipton, Professor at Albert Einstein College of Medicine in New York.
"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," Lipton added.
About 30 million women and girls play football worldwide, according to the International Federation of Association Football, known as FIFA, the international governing body of football.
In the study, Lipton and his colleagues performed diffusion tensor imaging (DTI), a form of MRI, on 49 male and 49 female amateur football players.
Both groups ranged in age from 18-50 with a median age of 26, and both groups reported a similar number of headings over the previous year (an average of 487 headings for the men and 469 for the women).
DTI detects subtle brain damage by measuring the direction of the diffusion of water in white matter (the deep brain tissue that coordinates communication between brain regions).
The more uniform the diffusion of water - measured on a zero-to-one scale called fractional anisotropy (FA) - the better the microstructural integrity of the tissue. Finding a low-FA brain region indicates structural damage to the brain.
Assessment of fractional anisotropy in players' brains showed that the volume of damaged white matter in women soccer players was five times greater than for male players.
The women had eight brain regions where greater levels of heading were associated with lower FA compared with only three regions in men, the study found.