Almost three-quarters of biomedical studies do not report whether the outcomes differ for men and women, according to a study that raises concerns about gender bias.
Analysis of more than 11.5 million medical research articles published between 1980 and 2016 found that a majority overlooked the role of gender differences in genetics, physiology and the way the body responds to medicines.
"Female participants are often underrepresented or excluded from research, with all the consequences," said Vincent Larivière of the University of Montreal, senior author of the article. "The inadequate attention to gender differences … has had disastrous consequences."
For example, the note noted that of the ten medicines withdrawn from the market between 1997 and 2001, eight health risks were greater for women than for men.
In many studies and clinical trials, the exclusion of women was justified on the grounds that their physiology is less stable due to the menstrual cycle. However, the paper states that "recent empirical research has shattered the myth of women's variability" by showing that men exhibit more variability than women on different traits.
The uptake of women in clinical trials has increased, according to the study, but at the same time the bias of the male has increased in animal and cell culture studies.
The study showed that female authors were more inclined to report on gender differences and that magazines with a high impact report sex less quickly. Between 1980 and 2016, gender-related reporting increased in all types of health research included in the paper: from 59% to 67% in clinical medicine and from 36% to 69% in public health. Progress in biomedical research, however, was slower and increased from 28% to 31%.
The study was published as part of a series of articles in the Lancet on the progress of women in science and medicine. One comment noted that medical textbooks are also highly biased, with the male body remaining "the norm." In 31 anatomy manuals published between 1890 and 1989, approximately 70% of the anatomical drawings were male, compared with less than 10% female (the remainder being classified as non-sexes). A more recent survey of 15 general medical and surgical textbooks showed that 78% of the depicted faces were male.