IN 2016, a group of researchers in Canada released a paper that completely upended the gold standard for survivorship of heart disease. For years, study after study had shown that mice have a better chance of surviving a heart attack that hits during the day. . How come?
The answer turned out to be simple. All the previous – implicitly gender-neutral – mice had been male. These new mice were female.
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It is perhaps no coincidence that women have lower survival rates for heart attacks than men. That sex matters is a message that has been repeated by biomedical researchers for decades. The past couple of weeks have seen three further calls for researchers to stop using males as the default sex in their work.
Writing in the journal Science, neuroscientist Rebecca Shansky at Northeastern University in Boston the underlying premise that hormonal activity makes female bodies and brains too variable to be good research subjects. This assumption wasn’t even tested until 2014, when a of almost 300 studies found that male mice were, in fact, more variable than female mice on certain markers.
Over-reliance on male data goes beyond animal research, too. As science journalist highlighted in The New York Times, men far outnumber women in HIV trials. This is despite the fact that women make up the majority of those with HIV, and that the virus is the leading cause of death among women of reproductive age worldwide. We know that men and women react differently to the virus, probably because male and female immune systems are different.
As a series of articles just published by The Lancet on makes plain, this isn’t just about biology. The disparity between the roles and opportunities afforded to men and women is reflected in health outcomes. Many of the challenges women face are because their rights aren’t protected, and restrictive gender norms are woven into the fabric of health systems and research.
These latest interventions should all be welcomed, but will they achieve anything? After all, we have known about many of these problems for decades, yet progress remains achingly slow. The US National Institute for Health (NIH) now mandates the inclusion of females in the research it funds, but compliance remains patchy. As Shanksy points out, the NIH doesn’t explicitly dictate how to incorporate both sexes into experimental designs. Too often, researchers conduct studies in men first and only progress to including women if they find something interesting, which, once again, positions men as a standard from which women deviate.
We need better, stronger and more well-enforced regulation. The truth is that, because of the need to test at different stages of the menstrual cycle, it probably is more expensive to include women in clinical trials. But we must ask ourselves a simple question. What do we care about more: saving money or saving lives?
