While scientists are increasingly including females in their research, a study has found they’re still not analyzing findings based on sex. This could have serious implications in understanding how diseases, drugs, and vaccines affect men and women differently.
The study, published in eLife, is a 10-year-follow-up to a 2009 study which had found females were left out of biomedical research. To see where we stand today with regards to the inclusion of females, a team of researchers from Northwestern University and Smith College examined more than 700 scientific journal articles from nine fields published in 2019. They checked for female representation as subjects in research including animals in lab experiments and humans in clinical trials. Then they studied if scientists discussed results based on the subjects’ sex.
On a positive note, researchers found that in a decade, the inclusion of females in studies had grown from 28% to 49%. However, in eight of the nine fields studied, there was no change in the proportion of results analyzed by sex. In the remaining one, the numbers actually dropped by 4%.
“The implications of not analyzing research data by sex are endless,” said Nicole Woitowich, lead author of the study and research assistant professor at Northwestern University Feinberg School of Medicine. “Without this, we have no way of telling if or how new drugs and therapies may work differently in men and women. It hinders progress toward personalized medicine and it also makes it difficult for scientists to repeat studies and build upon prior knowledge.”
When scientists don’t analyze data by sex, it forces them to make assumptions about their findings, which ultimately hampers their understanding of health and disease in both the sexes. This can become an impediment in understanding the way males and females respond to treatments, or get access to them.
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Further, the authors noted only 4% of the published studies provided a reason for why they didn’t use both the sexes or analyze data by sex. Many said it was to control the influence of female hormones as it may complicate findings or interrupt study designs, although this is an assumption which has been proven false a number of times, Woitowich said.
By not sharing information on methodology, there are chances that the studies may not be built upon, looked into further or be reproduced in the future.
“One of the basic tenets of scientific research is that we share our methods so that people can repeat our work and build on it,” Woitowich said. “And if we don’t have even the most basic information of, say, this study used 10 mice, five of which were female, five of which were male, I think that’s going to play a huge role in our ability to reproduce studies.”
Therefore, the findings of the current study not only provide an insight into how little we know about females’ health and how that might be limiting chances of developing personalized treatments for them, but also that it is time for funders and scientific journals to keep a watch on the discrepancies in methodology. In addition, it is also a call for academicians and scientists to educate their students about the importance of inclusion in various stages — from having an equal number of participants to considering their sexes while deriving at results to ensure problems are addressed adequately and efficiently.
