Ending Sex Bias in Medical Research Starts With Lab Mice

The U.S. National Institutes of Health wants scientists to include more female laboratory animals and cells in early studies to better understand how women respond differently to medications.

The new policies will require researchers applying for NIH grants to report plans for avoiding gender bias in early lab studies, NIH director Francis Collins and Janine Clayton, director of the NIH’s Office of Research on Women’s Health, wrote in the journal Nature.

Researchers have known that women respond to certain treatments differently than men and have made efforts to get more women included in clinical trials. Women now make up more than half the participants in NIH-funded studies. Yet the majority of early testing is done on male animals and cells. That disconnect may explain why some results in animals aren’t replicated in human studies, the researchers wrote.

“In requiring sex and gender inclusion plans in preclinical research, the NIH will ensure that the health of the United States is being served by supporting science that meets the highest standards of rigor,” Collins and Clayton wrote yesterday in the journal.

Women are more likely to have side effects from drugs and in some cases require different doses, studies have found. For example, women are recommended to take a lower dose of the sleeping drug Ambien after studies found they had higher levels of the drug in their blood the following morning.

Researchers have typically used male lab animals over concerns that the hormonal changes from female animals’ menstrual cycles would throw off results, the Nature paper said. Those concerns haven’t been validated in studies.

Earlier Guidelines

In 1994, the NIH released guidelines for the inclusion of women and minorities in clinical trials to ensure that the safety and efficacy of drugs would be studied in a full range of patients that might use the treatments. Women had previously been excluded from studies, resulting in inadequate information about the effects of drugs on women.

Even the study of female genitalia in animals has lagged PLoS Biology found. The research, which analyzed 364 papers published from 1989 to 2013 on the evolution of genitalia found that 49 percent studied male genitalia compared with 8 percent that focused on female genitalia.

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