Happy International Women’s Day!
One of my favourite questions is neuroscience right now is how concussions affect men and women differently, so I thought today was a great day to talk about concussions are different for women than for men.
One of the important things to consider when comparing injury data between men and women is the difference between sex and gender. Sex is biology: a person’s chromosomes, hormones, and sex organs. Gender is imposed by the culture in which we live: it relates to how a society defines masculine vs. feminine. I don’t distinguish here between gender- or sex-based data here - because in most cases we discuss, there’s an interplay.
Concussion rates are higher in women
First of all, while males get more concussions than females as a group, when you compare sports played with similar rules and equipment by both sexes, females appear to have a higher incidence of concussion. A Canadian study of varsity hockey players counted how many concussions players got, and found that across the regular season, men sustained 7.50 concussions per 1000 athletic exposures and women sustained 14.93 (1).
So what’s going on here? Perhaps there’s a gender-based difference in reporting: maybe women report concussions more readily than men, although this study only counted concussions that were observed and confirmed by on-ice physicians. But perhaps there is some unconscious, implicit bias in how these physicians observed men’s hockey as compared to women’s.
Women are at greater risk for persistent symptoms
When we look at recovery from concussion, women and girls often struggle more than men or boys. Persistent symptoms, also sometimes called post-concussion disorder (PCD) or post-concussion syndrome (PCS), is considered the failure of normal clinical recovery, specifically defined as “symptoms that persist beyond expected time frames,” which are 10-14 days in adults and 4 weeks in kids (2). The Consensus Statement on Concussion in Sport includes one sentence on women and girls specifically, which reads:
There is some evidence that the teenage years, particularly the high-school years, might be the most vulnerable time period for having persistent symptoms— with greater risk for girls than boys.
The reasons for the higher risk of persistent symptoms in girls is not yet clear. Is it related to reporting again? Or maybe it’s more sex-based and related to hormones or body structure.
Hormones may play a role
This is a topic that I find simultaneously fascinating and frustrating. There is a growing body of evidence that hormones play a role in the incidence and the experience of concussion. The exact role of sex hormones, though, is poorly understood. We know that sex hormones (including estrogen, progesterone, and testosterone) affect more than just the sex organs - they have effects on the brain, too. There are studies that have shown that women are likely to have a poorer recovery from concussion during their child-bearing years, suggesting that estrogen and progesterone play some kind of role (3).
There are some big questions that remain unanswered: Does the phase that a woman is at in her menstrual cycle at the time of injury affect how she recovers? Does the brain injury mess with hormone production, or do hormone levels at the time of injury? Can we give hormones to help recovery? Unfortunately, at this time, we just don’t know.
Women report more symptoms, and more severe symptoms
There is a flood of data that shows that after concussion, women report having more symptoms than men do, and they rate the symptoms as more severe. I’m not going to re-state all of the stats, just Google if you don’t believe me. I’m more interested in WHY.
Is there a sex-based reason why women report more symptoms or worse symptoms? Maybe it’s related to hormones, which we know are radically different between the sexes. Maybe it has to do with women having, on average, smaller bodies or less neck strength. Or is the reason gender-based? We know girls and boys are socialized differently from birth. Boys are encouraged to “suck it up” more than girls, so maybe, as adults, females are more willing or able to accurately report how they’re feeling, or males are more apt to hide or downplay symptoms.
Women get concussions in different ways than men
When we think of concussion, we often think of contact sports like football. Fewer women play football than men, so you could be forgiven for thinking that concussion is primarily a male problem. But 30% of women worldwide experience intimate partner violence, and this is a major cause of traumatic brain injury, including but not limited to concussion (4). Accurate statistics are hard to calculate, because these women may not self-identify, but it’s vital we as health care providers try to check our biases. It’s not just the athletes who get concussions.