Essay Series 4.2: U.S. medical research has focused on men’s health to the detriment of women.

Men controlled medical research for decades and focused on their own concerns. It wasn’t until the 1990s that the National Institutes of Health required that women be included in research. Even when included, researchers still aren’t required to analyze women’s data separately from men’s. Since women’s bodies differ from men’s, failing to study them has harmed women. Both sexes can be harmed when data analysis lumps them together.

Failure to Include Women in Studies about Women’s Health

Almost everything we think we know about human health comes from male humans, male animals, and male cell lines. Women often were excluded from research that the National Institutes of Health (NIH) funded and from the drug trial results submitted to the Food and Drug Administration (FDA) between the 1960s and 1990s. This led to some odd studies. In the 1960s, researchers studied whether hormonal supplementation would help women, but only enrolled men in the experiment. A 1986 study on the effects of obesity on breast and uterine cancer didn’t include women either.²²¹

This situation started changing in the 1990s. The NIH opened an Office of Research on Women’s Health in 1990 when gynecological symptoms of AIDs began showing up. In 1993, NIH required that researchers include women in clinical trials and that all federally funded clinical research needed to prioritize including women and underrepresented racial and ethnic groups. However, NIH didn’t require researchers to compare women’s and men’s results or to include sufficient numbers of them to determine if research results differed by sex.^222,223

Partial Solutions

It wasn’t until 2014 that NIH acknowledged that there had been widespread male bias in pre-clinical trials.²²⁴ In that year, the NIH required that all animal research consider sex as a biological variable.²²⁵ By 2016, NIH required inclusion of women as a condition of receiving research funds.²²⁶

Studies in 2010 and 2020 showed that not much has changed. Women are still underrepresented in research studies. In addition, female animals aren’t often included in the research that precedes human studies.²²⁷ Researchers examined over 700 NIH-funded and published studies from 2009 to 2019. By 2019, about half of the studies included women. However, the percentage of studies analyzing women’s data separately didn’t improve during that time.²²⁸

Some examples of harm from failing to include a sufficient number of women in research or to analyze data by sex relate to drug dosages and heart disease. The vast majority of drugs have sex-neutral dosage recommendations, despite the fact that women metabolize drugs more slowly than men.²²⁹ For example, the Food and Drug Administration (FDA) had to cut the recommended doses of Ambien in half for women because of these differences.²³⁰

Regarding heart disease, studies of men predominate, and women were less than a third of the participants in landmark studies of cardiovascular disease between 1987 and 2012. Heart disease is the leading killer of women. Yet models used to predict heart disease rely on data from men.²³¹ A study found women under age 55 are seven times more likely to be turned away during a heart attack than the average patient.²³² By the 1980s, cardiovascular deaths among men were declining, but they were rising for women. In fact, women are more likely to die within one year of a heart attack than men. And women’s symptoms of heart disease often get brushed off with diagnoses of depression, anxiety, acid reflux, and other conditions. This situation is worse for Black women.²³³

Reflections

Failing to include women as well as female animals and cell lines in medical research has several results:

1. Researchers have failed to adequately study half the human race.

1. The medical profession often dismisses women’s symptoms and pain, assumes that symptoms are psychological, under-diagnoses serious illness, and gives women the wrong drugs or doses of drugs.

1. Disability and unnecessary pain are two other likely results of failing to include women or separately analyzing their data.

1. Failing to analyze women’s data separately from men’s may lead to errors that could affect either sex.

How many women have died as a result of bias toward men in medical research? I haven’t seen this number quantified, but the number likely is in the tens of thousands, if not much higher.