For the past twenty or so years, changes have taken place in international medical research so as to incorporate the gender issue in research practices and topics. The objective is to take into account the way in which social roles and cultural context affect women's and men's health from a physiological and pathological perspective. Incorporating gender in medicine and research is a response to both scientific and ethical questions. This involves fighting against inequality and discrimination affecting men and women in the field of health.
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Understanding the issue
Men and women do not benefit from the same conditions in terms of health. However, biological differences are far from being the only reason: social perceptions related to the female or male gender influence the attitudes of patients, the medical profession, and scientists. Examining the relationships between gender and health allows for ethical consideration of the way in which social and cultural factors contribute to health inequalities between the sexes. This approach aims to expand knowledge on the origins of the differences between men and women in health, to improve clinical practices, and in biomedical research.
Sex and gender: a way of incorporating all decisive factors for health status
In order to understand the gender issue in terms of health, it first needs to be defined:
- Sex describes the biological characteristics (chromosomes, genital organs, hormones, reproductive function) which differentiate males from females, including in the human species.
- Gender corresponds to the non-biological differences which distinguish individuals from each other: this concept describes the social and cultural construction processes for female and male identities, the processes for social relations between the sexes.
Sex and gender are not separate variables: they merge as part of an interactive process between biology and social environment which develops from birth, or indeed even earlier. It is important to encourage physicians to take the differences between males and females into consideration, not as a simple dichotomy between male and female, but as the result of intricate links between sex and gender. Health research should take this connection into account in order to explain both the differences and similarities between males and females in terms of physiology and pathology. Approaching medicine from the sex and gender perspective offers a more precise vision of health inequalities and their causes.
Delayed awareness in France
Awareness of this issue first came to light in the United States, between the end of the 1980s and the beginning of the 1990s, based on the need to incorporate the gender dimension in order to rethink medicine and research. Already aware of the issue, owing to research in social sciences, several female members of Congress made changes to US legislation: they obliged the governmental public health research organization, the National Health Institute (NIH), to adapt its research policy to take into account a more balanced concept of sex and gender in its research (as well as for ethnic minorities). Since 1990, the NIH has thus had a specific office (Office of Research on Women's Health) and a steady budget with this aim in mind. At the same time, the Food and Drug Administration (FDA), responsible for approving medicinal products, made changes to the quality criteria of clinical trials conducted in therapeutic research, henceforth including the representation of women.
Further to these early North American initiatives, in 2002, WHO adopted a policy approach to issues of equity between the sexes and according to gender. This took the form of different projects, primarily aiming to resolve the health challenges facing motherhood, violence and sexually transmitted infections.
Awareness of this issue emerged later in Europe. This was first observed in countries like Germany, and in Northern European countries, which focused attention on the concept of gender-based medicine. More recently, the European Commission already included gender equality in its criteria for scientific excellence.
From the early 2000s, several French research organizations began to take up the issue, such as the Institut national d'études démographiques (INED - National Institute of Demographic Studies), CNRS and Inserm. In 2013, the Inserm Ethics Committee created a working group on the theme of "Gender and health research". This aimed to raise awareness among the institute's scientists and physicians on the issue of health inequalities related to sex and gender, and to take into account these specific aspects in clinical practice and research.
Gender and medicine: taking into account the weight of social representation, for improved medical and research practices
Sex and gender are inextricably linked: the health status of an individual may be influenced by the nature of their occupation, level of education, and lifestyle. These decisive factors often differ between men and women, due to their different social and cultural contexts. For example, most men usually tend to seek medical advice later than women. The physician/patient relationship may also be influenced (often unconsciously), by gender-related social perceptions. Research in the field of social science, which offers valuable additional insight into this issue, reveals the extent to which social codes for femininity (fragility, sensitivity, verbal expression) and masculinity (virility, resistance to harm, risk-taking) play a role in the expression of symptoms, the relationship with the body, and recourse to health care. It has also shown how these stereotypes influence the way in which health care professionals screen for and treat certain disorders. Taking into account the connection between sex and gender raises questions on the way in which these differences have emerged in terms of health, thereby allowing an appropriate solution to be found. This is an essential part of the ethical debate which should promote the development of good practices, or indeed new practices, whether in the research or clinical domain.
A few examples illustrate the importance of taking both sex and gender into account in medicine and biomedical research:
Myocardial infarction is a typical example of the interaction between sex and gender. The risk of infarction has long been associated with the image of the older male with a stressful occupation. Therefore, this disease is under-diagnosed in women. A female patient who complains of tightness in her chest will be prescribed anxiolytic drugs, whereas a man will be referred to a cardiologist. In certain cases, infarction symptoms may have an atypical presentation in women. The risk of late diagnosis and management is therefore common. This explains why the majority of infarction-related deaths currently concern women.
In contrast, osteoporosis is under-diagnosed in men as it is perceived as a disease which affects menopausal women. However, a third of femur neck fractures in men are due to osteoporosis. Consequently, the risk of a second fracture is as high in men as in women
Depression is often perceived as a predominantly female disorder; however, it occurs as often in men if we take into account diagnostic criteria for atypical symptoms, such as aggression and increased harmful behaviors (alcohol or drug use, dangerous driving).
There are numerous examples of the influence of sex and gender on health, in practically all fields of medicine: cancer, diabetes, obesity, pain, asthma, osteoarthritis, addiction, aging, etc.
The brain: between sex and gender
At the start of the century, anatomists concluded that men were more intelligent… because their brain weighed 1,350 grams on average, i.e., 150 grams more than women's brains! It is now known that it is the quality of the connections between the nerve cells which determines cognitive capacity, and not organ weight.
For over 10 years, MRI studies have demonstrated that learning and life experiences modify brain structure and function: this is known as brain plasticity. Brain structure and function is thus specific to each individual: there may be fewer differences between the brains of a man and woman than between two individuals of the same sex. Moreover, perceiving differences between the sexes does not mean that these differences were inscribed on the brain from birth, or that they will remain so (owing to the properties of the brain in terms of plasticity!).
Hence, in neuroscience and other fields, it is vital to raise the question of the origin of the differences which may be observed between men and women's brains, before concluding as to differences in innate predisposition. It is essential to take into consideration variables other than biological sex when comparing men and women's brains: level of education, occupation, activities (sports, games), ethnic origin, social situation, marital status, economic status, etc. For instance, aptitude tests show that, on the whole, boys generally have better spatial orientation abilities than girls. However, when these abilities are studied in girls having regularly played video games, the results of these tests are equivalent to those achieved in boys. This is proof that the difference in result is not related to sex, but to different cultural practices.
Other example: girls and boys were given two drawings depicting a complex 3D shape, in a different position. The investigator asked them to determine whether both drawings depicted the same shape or not. When this exercise was presented to the children as a geometrical problem, boys gave the correct answer more often than girls. In another group, the exercise was presented as a drawing test: in this case, the girls gave the correct answer more often, thus demonstrating the impact of social perceptions related to sex.
Challenges facing research
Sex, gender and biomedical research
Analysis of the relationships between sex, gender and health does not fall within the scope of a specific research discipline, but corresponds to a cross-cutting approach which includes every aspect of the human being with the aim of understanding or resolving health problems. This calls for methodological changes in practices.
In the context of preclinical research (in vitro or animal studies), questions may arise as to the sex of cells and animals being studied.
- At cell level, even aside from sex cells (gonads, gametes), certain mechanisms have been shown to differ according to sex, in various tissues. These microscopic data are well documented. However, their consequences on the body in general are unclear, particularly in the human species.
- As regards animal studies, numerous tests are conducted in male animals only. The reason put forward is that female hormone cycles lead to variations in behavior. However, according to recent studies, it appears that this is not necessarily the case: these studies in fact show that the main factor for variations in behavior in rodents is the number of animals confined to the cages, and not sex.
Studies in the context of clinical trials have mainly been conducted in male subjects. Studies on the risk of gynecological cancers have even been conducted in males! Faced with this divergence in the pharmaceutical industry, legislation have now made it compulsory to conduct clinical trials on subjects of both sexes, for the past 30 years in the United States, and over the past 15 years in Europe.
Opening up medical research to the issue of sex and gender is perceived as a new opportunity to raise questions as to the validity of the models conventionally used in research protocols and to challenge existing practices so that more reliable methods can be developed. This approach represents an innovation in medicine, with optimum benefit for men and women, and has led to higher quality research.