Earlier this week, when discussing the recently implemented National Institutes of Health (NIH) grant requirement that proposals cover how sex is accounted for as a biological variable, I commented on the length of time it has taken to get to this point.
“While some of this time can be accounted for by the typical time required in developing policy I think it also highlights the challenges in confronting and mitigating a longstanding bias against systematic consideration of sex in biomedical research.”
I mentioned in that post a 2015 GAO report noting the problems NIH grantees have had in incorporating women into clinical trials. However, this Nature news article describes the problems ahead for addressing sex differences in research animals. It discusses a paper in eLife that describes an analysis of sex differences in research mice used in over 15,000 open access research papers published between 1994 and 2014.
While researchers did find that recording data on animal studies improved over the time series of the study, it plateaued around 2010. So the existence of subsequent policies, like that of the NIH, has not yet translated into further improvements. The study also noted that certain research fields have strong preferences for either male or female research mice. These differences were also found in different kinds of research in the same field (the Nature article notes that diabetes research tends to use male mice, but studies on immunology related to diabetes tend to use female mice.
It would seem that policies will only be one tool used in order to successfully manage the use of both genders in research mice for biomedical research. Education and journal practices will need to adapt to make sure researchers understand why sex is an important variable in their research that needs to be address much better than it has until now.