Teenage girls twice as likely as boys to be concussed while playing football
A Glasgow University study analysed injury data from around 80,000 American high school footballers.
Teenage girls who play football are almost at double the risk of concussion compared to their boy counterparts, according to a study.
Professor Willie Stewart at the University of Glasgow reviewed three years of injury data of around 40,000 female high-school footballers in the United States of America.
Working with researchers at the University of Pennsylvania and Michigan State University, he compared data for a similar number of male footballers and found risk of sports-related concussion among female footballers was almost double - 1.88 times higher.
Prof Stewart, senior author of the study, says the reasons why girls are affected isn't clear, but there are theories and loosely researched topics that could provide details.
He said: "There's been very little research looking at why male and female athletes have differences in concussion risk.
"Some of the best work has looked at fine fibres in brain cells, that show females have slender fibres and are perhaps at more risk of damage than males' more robust ones.
"There are some subtle differences in male and female neck strength as well which might be responsible and, finally, there's been some work looking at the menstrual cycle which suggests that females are at greater risk of concussion towards the end of their cycle."
The study concludes teenage girls are less likely to be removed from play and take on average two days longer to recover from injury and return to play than boys do.
Male footballers were most often injured colliding with another player and were 1.5 times more likely to be removed from play on the day of injury. According to the findings, females were most often injured from contact with equipment such as the ball or a goalpost.
Prof Stewart added: "For the first time we've shown that the reasons for getting concussion and the mechanism of it are different.
"Boys are more likely to be concussed when colliding with an opponent or team-mate, while girls are more likely to be hurt colliding with equipment, which in football is the ball.
"It looks as though heading the ball is a riskier event for girls.
Despite what may jump-out as an alarming statistic for girls keen to continue playing the game, Prof Stewart is keen to hammer home the point that although they are more likely than boys to be concussed, the overall likelihood still remains very low.
He continued: "As far as concussion goes, football is a low risk sport. Even in our study or 80,000 boys and girls in the USA, only two per cent of them suffered a concussion during our timeframe so it's an infrequent event.
"But, it's important to understand the risk is there. It's not just the immediate concussion either, but the low level impacts. If there's a higher risk of concussion in female athletes then is there a higher risk of problems in later life?
"There needs to be more research for female athletes and more caution taken with them overall."
Dr Abigail Bretzin is another lead author of the study, a postdoctoral fellow and certified athletic trainer at the University of Pennsylvania.
She said: "This is the first study to look in this detail at sex-associated differences in concussion management and outcomes in teenage footballers.
"Our findings add to research showing that female athletes are at increased concussion risk compared to male athletes, and highlight the importance of sex-specific research in this field.''
Professor Stewart's work has been funded by the Football Association and the Professional Footballers' Association, NHS Research Scotland, the Penn Injury Science Center and a Brain Injury Training Grant.