Historically, including sex as a variable in scientific research has been rare, and a newly published study shows there has been no increase in the number of studies to analyze data by sex in the last decade.
Researchers analyzed more than 700 scientific articles and noted which studies used male, female or both sexes as participants and which ones reported and analyzed data by sex. The new study, published in the journal eLife, is a 10-year follow-up to a study published in 2009, which found that the female sex was often left out of biomedical research.
The new study shows that the number of studies including both male and female subjects increased from 28 percent in 2009 to 49 percent in 2019. But the number of studies to break down and analyze the data by sex did not increase in the same 10-year period.
Not analyzing data by sex may have harmful implications, including scientists making assumptions based on the missing information, said study author Nicole Woitowich, PhD, associate director of the Women's Health Research Institute at Northwestern University and research assistant professor at Northwestern University Feinberg School of Medicine in Chicago.
"Without [analyzing research data by sex], 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," said Dr. Woitowich.