NIH-Funded Studies Often Overlook Sex Differences in Research Reporting, Study Finds

Fewer than half of research papers published by researchers funded by the National Institutes of Health (NIH) analyze or report their data by sex, according to a new study. This gap could obscure the relevance of findings for men and women.

Over a decade ago, the NIH introduced guidelines to promote sex-inclusivity in study design by requiring researchers to consider sex as a biological variable (SABV). The guidelines encourage researchers to integrate SABV into study design, analysis, and reporting, but they do not mandate that sex differences be examined in the results.

The study, published in JAMA Network Open, analyzed 1,382 papers from 2016 to 2020 funded by the NIH. Key findings include:

• 42% of papers reported sex-specific data, with only 26% analyzing sex differences in their results.
• Papers in neuroscience and immunology were less likely to report sex-specific data compared to other fields.
• Researchers in the United States were more likely to report sex differences than those in other countries.

The study’s authors emphasize that the lack of sex-specific reporting limits the ability to draw conclusions about how findings apply to different sexes, potentially affecting the accuracy and applicability of medical research.

"The NIH’s policy was a significant step forward, but our findings suggest that more needs to be done to ensure compliance and meaningful integration of sex as a biological variable," said Dr. Londa Schiebinger, lead author of the study and a professor at Stanford University.

The NIH’s Sex as a Biological Variable (SABV) policy, introduced in 2016, requires researchers to account for sex in their study design, analysis, and reporting. However, the policy does not enforce the examination of sex differences in the results, leaving room for variability in compliance.

Experts argue that greater emphasis on sex-specific analysis could improve the precision of medical research and lead to more tailored treatments for men and women.