Male and female bodies are biologically different. But a new study from the University of British Columbia found that only 53 per cent of health research studies included both bodies.
The study comes from Dr. Liisa Galea, a professor in the department of psychology. She analyzed 3,193 neuroscience and psychiatry studies from 2009 to 2019.
According to Dr. Galea, the analysis was motivated by a separate study that highlighted women are diagnosed on average two years later than men for the same diseases.
“We know that women are more likely to live longer than men, but they are also more likely to suffer from chronic disease and side effects from new drugs,” said Dr. Galea in a press release.
And although health research funding agencies in the U.S. and Canada have tried to correct disparities by mandating female inclusion, Dr. Galea said disparities are still seen across a wide variety of diseases.
“The majority of studies in our sample did not analyze the data with sex as a factor. Of the studies that did, most of the studies thought of sex as a “nuisance” variable and used it as a covariate, which is a way of removing the effect of sex. That’s a problem, because you’re simply removing the variable rather than looking at whether it made a difference.”
In fact, removing sex as a factor has its consequences.
“When researchers look for sex differences, they often find differences in risk for disease or prevalence of disease," she said.
And diseases can also manifest differently in male and female bodies.
For example, when males experience a heart attack, they might feel chest pain. But women are more likely to “just feel sick,” said Dr. Galea. As a result, they are often sent home, which can cost lives.
When it comes to medication to help diseases, analyzing its effects on male and female bodies is important.
“Lazaroids are therapeutic drugs that can help limit damage from a stroke. It turns out they are very effective in males but not in females, which you wouldn’t discover if you didn’t analyze for sex differences,” she said.
In more recent cases, Dr. Galea noted the effects of COVID-19 vaccines and pregnant people.
“Initial clinical trials did not use pregnant people. They also didn’t record any possible effects post-vaccine that would affect men and women differently such as a menstrual cycle disturbance. When women started reporting this on social media, it caused confusion, misinformation and likely contributed to some vaccine hesitancy."