Possible reasons for these sex differences may include female sex hormones: rat studies show that estrogen has both protective and exacerbative effects, Dr. Carlson said. Cerebral blood flow and basal rate of glucose metabolism are higher in females than in males, and perhaps an increase in either of these after injury may cause concussion symptoms to persist or be more severe, she speculated.
There’s nothing gender specific about concussion-prevention efforts, except perhaps how they’re applied. Boys playing lacrosse are required to wear helmets, for example, but girls are not, she said. Concerns about universal use of headgear leading to more aggressive play and more collisions come from studies of boys, she added.
Regulations may play an increasing role in preventing concussions. A 2011 California law requires that players with suspected concussion must be pulled from school-based sports and not allowed to return without clearance from a health care profession, and they must get yearly head-trauma clearance.
Female participation in high school sports increased 900% in the past 40 years and increased 500% in collegiate sports. It’s not just the older girls who are at risk, though. Recent trends of increased participation in organized sports and greater specialization in sports at younger ages may contribute to overuse and sport-specific injuries at younger ages, Dr. Carlson said.
"My 3-year-old already gets flyers for soccer teams," she said.
Dr. Carlson reported having no financial disclosures.