Lots and lots of women

For many years, medicine was a man’s business. Photos of professors of old show only distinguished men. The time when women were first allowed into medical school varies per country, but usually it was in the late 1800s – in The Netherlands, Aletta Jacobs was the first woman to graduate as a medical doctor from Groningen University in 1878. Nowadays, women are well represented among medical students – in Europe, they form the majority. In the past, patients were also predominantly men, that is to say, clinical studies mainly included Caucasian males, who were seen as the standard patient, and hence treatment was administered in a ‘male fashion’ to men and women alike. It has only recently been recognised that the sexes truly differ, for instance in the symptomatology accompanying a specific disorder, and the efficacy and effectiveness, or side effects, of various therapies. Again, over the last decades it has been recognized that these differences are relevant and that research, be it etiologic, diagnostic or therapeutic, should target both men and women. An important distinction is between sex and gender, both of which need to be taken into account. Sex is defined as the differences resulting from the number of Xand Y-chromosomes an individual carries. Gender is a more recent term, coined to indicate one’s identity and social and psychological roles. So, in biomedical literature one would expect the word ‘sex’ to be more common than ‘gender’, and the opposite in sociological publications. Nevertheless, ‘gender’ has become increasingly and inappropriately used in medical literature. This may be the result of awareness of the relevance of social and cultural constructs, but we fear it is to a large extent misplaced puritanism, because ‘sex’ may also refer to an act. In this issue of JTH, in which data from humans and mice are reported, females outnumber males by about 250 : 1. There are five studies specifically asking questions related to sex, and four that exclusively include female participants. In several of the laboratory studies, blood from human donors and patients is used of whom the sex remains undisclosed, as is the case of the mice in several experiments. One study, however, exclusively including female mice reports that a plasminogen receptor is required for lactating and successful weaning of baby mice. Four human studies report on sex differences or sex-specific effects. In one, it was asked whether decision rules to diagnose pulmonary embolism performed equally well in women and men. As for characteristics such as sensitivity and specificity the tests performed equally well, but fewer women who were investigated actually had pulmonary embolism than referred men. This points to differences in symptomatology, but since more women than men were referred, this difference was apparently adequately dealt with. Then there are three studies that only included women, ranging from 16 to 1.3 million subjects. In the first, a new factor X concentrate was given with good results to 16 girls and women with factor X deficiency. Bleeding disorders are typically sex-specific: some, such as the classical hemophilias, only occur in men. However, those that occur in both sexes, such as factor X deficiency, often cause most medical problems in women, due to menorrhagia and postpartum bleeding. There is little doubt that the social consequences of the former have been partially ignored in the past in the male-oriented medical world. In the study of over a million women, the question was whether exposure to radiation by computed tomography (CT), e.g. to diagnose pulmonary embolism, during pregnancy would increase the risk of breast cancer later in life. The rationale is that during pregnancy mammary cells proliferate and hence may be particularly sensitive to the deleterious effect of radiation. Finally, this issue contains an ancillary analysis of 100 000 women who participated in studies on the effects of postmenopausal hormones. The authors hypothesized that women who suffered vasomotor symptoms during menopause, such as hot flushes and night sweating, might have these as a marker of underlying vascular vulnerability, and hence have an increased risk of venous thrombosis. This appeared not to be the case. So, we are happy to recommend this particularly women-friendly issue of JTH.