Invisible Women: Exposing Data Bias in a World Designed for Men

clearly a long way to go, and we must begin to address these gaps as a matter of urgency, because while they remain open, women (who ingest approximately 80% of pharmaceuticals in the US¹¹⁹) are dying. Some drugs used to break up blood clots immediately after a heart attack can cause ‘significant bleeding problems in women.’¹²⁰ Other drugs that are commonly prescribed to treat high blood pressure have been found to lower men’s mortality from heart attack – but to increase cardiac-related deaths among women.’¹²¹ Statins, which are regularly prescribed around the world as a preventative measure for heart disease have mainly been tested in men and recent research from Australia suggests that women taking statins at higher dosages may face an increased diabetes risk¹²² – which in turn is a higher risk factor for cardiovascular disease in women than in men.¹²³ In 2000 the FDA forced drug manufacturers to remove phenylpropanolamine, a component of many over-the-counter medications, from all products because of a reported increased risk of bleeding into the brain or into tissue around the brain in women, but not in men.¹²⁴ Drug-induced acute liver failure has also been reported more often in women,¹²⁵ and certain HIV medications are six to eight times more likely to cause an adverse drug reaction (ADR) in women.¹²⁶

In 2014, the FDA released a database of ADR reports between 2004-13 which showed that women are far more likely than men to experience an ADR: more than 2 million were recorded for women compared to less than 1.3 million for men.¹²⁷ Although around the same numbers of men and women die from an ADR, death is ninth on the list of most common ADRs for women, compared to first on the list for men. The second-most common ADR for women (after nausea) is that the drug simply doesn’t work at all, and data on the number of deaths that occur as a result of the drug failing to work is not available. We do know, however, that women are more likely to be hospitalised following an ADR,¹²⁸ and more likely to experience more than one.¹²⁹ A 2001 US study found that 80% of drugs that had been recently removed from the market caused more ADRs in women,¹³⁰ while a 2017 analysis points to the ‘large number’ of medications and medical devices removed from the market by the FDA that posed greater health risks to women.¹³¹

None of this should surprise us, because despite obvious sex differences, the vast majority of drugs, including anaesthetics and chemotherapeutics,¹³² continue with gender-neutral dosages,¹³³ which puts women at risk of overdose.¹³⁴ At a most basic level, women tend to have a higher body-fat percentage than men, which, along with the fact that blood flow to fat tissue is greater in women (for men it’s greater to skeletal muscle) can affect how they metabolise certain drugs.¹³⁵ Acetaminophen (an ingredient in many pain relievers), for example, is eliminated by the female body at approximately 60% of the rate documented in men.¹³⁶ Sex differences in drug metabolism is in part because women’s lower lean body mass results in a lower base metabolic rate,¹³⁷ but it can also be affected by, among other things: sex differences in kidney enzymes;¹³⁸ in bile acid composition (women have less);¹³⁹ and intestinal enzyme activity.¹⁴⁰ Male gut transit times are also around half the length of women’s, meaning women may need to wait for longer after eating before taking medications that must be absorbed on an empty stomach.¹⁴¹ Kidney filtering is also faster in men, meaning some renally excreted medications (for example digoxin – a heart medication) ‘may require a dosage adjustment’.¹⁴²

For millennia, medicine has functioned on the assumption that male bodies can represent humanity as a whole. As a result, we have a huge historical data gap when it comes to female bodies, and this is a data gap that is continuing to grow as researchers carry on ignoring the pressing ethical need to include female cells, animals and humans, in their research. That this is still going on in the twenty-first century is a scandal. It should be the subject of newspaper headlines worldwide. Women are dying, and the medical world is complicit. It needs to wake up.

CHAPTER 11

Yentl Syndrome

In the 1983 film Yentl, Barbra Streisand plays a young Jewish woman in Poland who pretends to be a man in order to receive an education. The film’s premise has made its way into medical lore as ‘Yentl syndrome’, which describes the phenomenon whereby women are misdiagnosed and poorly treated unless their symptoms or diseases conform to that of men. Sometimes, Yentl syndrome can prove fatal.

If I were to ask you to picture someone in the throes of a heart attack, you most likely would think of a man in his late middle age, possibly overweight, clutching at his heart in agony. That’s certainly what a Google image search offers up. You’re unlikely to think of a woman: heart disease is a male thing. But this stereotype is misleading. A recent analysis of data from 22 million people from North America, Europe, Asia and Australasia found that women from lower socio-economic backgrounds are 25% more likely to suffer a heart attack than men in the same income bracket.¹

Since 1989, cardiovascular disease has been the leading cause of death in US women and, following a heart attack, women are more likely to die than men.² This disparity in deaths has been the case since 1984, and young women appear to be particularly at risk: in 2016 the British Medical Journal reported that young women were almost twice as likely as men to die in hospital.³ This may be in part because doctors aren’t spotting at-risk women: in 2016, the American Heart Association also raised concerns about a number of risk-prediction models ‘commonly used’ in patients with acute coronary syndrome, because they were developed in patient populations that were at least two-thirds male.⁴ The performance of these risk-prediction models in women ‘is not well established’.

Common preventative methods may