Sex, gender and health research

1. Sex, gender and health research Lesley Doyal

2. ‘ The evidence base of medicine may be fundamentally flawed because there is an ongoing failure of research tools to include sex differences in study design and analysis ‘ Holdcraft A ‘Gender bias in research : how does it affect evidence based medicine?’ JRSM Jan 2007

3. Introduction • Evidence based health and medical care practiced on foundation of knowledge and skills • But is this ‘evidence ’ really based on an investigation of the needs of all those who will be treated? • Human beings heterogeneous and this is vital to generation of scientific knowledge • Sex/gender two of most basic categories of differentiation between individuals • But many research designs and data collection procedures do not recognise this reality

4. Failure to disaggregate routine health data • Most frequent form of data collection found in routine medical/health statistics • Failure to collect, present and analyse data by sex, limits knowledge base for public health • Disaggregation more common over past decade especially in work of international organisations • SA made progress at national/regional levels especially with DHS that asks gender related questions • For more detail see UN Statistics Division The World’s Women: Progress in Statistics 2005 http://unstats.un.org/unsd/demographic/products/indwm/wwpub.htm

5. Gender critiques of biomedical research • Began in US and Canada in 1980’s but now more widely disseminated • Gender bias in priority setting and choice of topics • Also domination of men as researchers and on ethics committees and funding bodies • But main focus on exclusion of women as research subjects • Most emphasis on clinical trials but bias in epidemiology and HSR also highlighted

6. How are trials biased ? Most samples only include young white men Women excluded on grounds that problem is ‘male’ (eg CHD, HIV) Also estrous cycle assumed to ‘mess up’ the results so cheaper and easier to exclude them Inclusion of women said to put potential fetus at risk even though most women not pregnant If women are included, numbers often too small to draw conclusions about m/f differences Even if numbers are large enough, differences often not analyzed When differences are found, failure to distinguish between sex/gender

7. What are effects of this on medical practice? • Drugs tested in one group are given to others with little concern for their appropriateness (1992 US study found less than 50% of prescription drugs tested on women) • Women offered same drugs as men despite their exclusion from trials….and some may be pregnant • Models of causality/risk factors derived from gender blind epidemiological studies used as basis for public health and health promotion strategies • Health services introduced without due regard for impact on all users; gender differences not included in audit , monitoring and evaluation • These effects pose serious challenges to optimisation of equity AND effectiveness and efficiency of care

8. Moving forward: reshaping research design in North America • Redefinition of ‘women’s health’ : not just repro health but problems unique to women, problems more common in women or presenting differently in women • Both US and Canadian government now mandate analysis of sex/gender results in clinical research • Emergence of legal strategies in pursuit of equity (US 1993 (NIH) Revitalisation Act) • US Offices of Women’s Health set up within NIH (1990) and in FDA; 15 year Women’s Health Initiative begun (1991) • Canada: creation of national Institute of Gender and Health as well as regional Centres of Excellence in Women’s Health • Highlight on women’s role as researchers as well as research subjects • Both countries published extensive gender resources to support researchers in developing new skills and building capacity to work in inter-disciplinary way • For Canadian guidelines go to http://www.cihr-irsc.gc.ca/e/32019.html

9. Have these approaches worked? • Some progress made but recent study by US General Accounting Office called it ‘just a weak and tentative beginning’ • New challenges have emerged in attempts to include appropriate number of women and men (and ethnic groups) • Increases size of studies and may also lead to pressure on subjects to consent to participation

10. Evidence of continuing gender bias • 2005: 8/10 withdrawals of prescription drugs in the US were result of problems experienced by women • A 2002 systematic review of 46 RCT’s on ARV’s found that only 12.25 % of participants were women and none provided analysis by sex (Pardo et al 2002) • Of all RCT’s in NEJM 1994-1999 only 24.6% of participants were women and gender analysis performed in only 14% (Ramasubbu et al 2001) • So much remains to be done

11. US research grants by gender (data from NIH 2005) )

12. Moving forward: including sex/gender in IRS and systematic reviews • Failure to include gender related issues appropriately in MeSH terms that provide framework for data searches For discussion of IRS issues See Ruiz-Cantero et al (2007) http://jech.bmj.com/cgi/content/full/61/Suppl_2/ii46 • Cochrane now moving towards equity issues (new field 2005) but sex/gender dimension still missing in most reviews • Most have little or no sex or gender data to draw on from original studies • But also need for capacity building and protocol design to ensure reviews include assessment of whatever sex/gender information available For recent Canadian discussion of this point see Jackson et al (2007)http://www.cewh-esf.ca/PDF/health_reform/genderWaitTimesEN.)

13. Gender and research in practice: cardiovascular disease • Burden of non-communicable diseases (including CVD) increasing everywhere • Often co-exists with infectious diseases especially among the poor • CVD accounts for 30% of global mortality and 10% of GBD • 80% of these deaths occur in low and middle income countries

14. CHD in women and men • Now clear CHD not just a problem for white middle class men in rich countries • World wide problem for women as well • CHD rates twice as high in men with earlier onset • But actual number of deaths in women and men similar because of longer female life expectancy

15. CVD in women around the world • 10/27 million female deaths each year caused by CVD of which 2/3 in dev co’s • Recent study found women at much greater risk of CVD than expected (Leeder et al 2004) • Brazil, Russia and SA: CVD cause of higher % of deaths in women than in men • Women in these countries also had higher rates than comparable women in US especially in younger age groups • Twice as many deaths from CVD as from pregnancy in Brazilian women 15-34

16. Three main critiques of medical research/practice in CHD • Differences between biology of chd in women/men not properly understood • CHD research rarely takes social or gender differences into account • Systematic bias against women in CHD prevention and treatment

17. Putting critiques into perspective • Not complete or consistent picture • Most studies have been small scale using a variety of methods • Most done in developed co’s especially US • But do show urgent need for greater sensitivity to sex and gender issues in CHD research • So look at each criticism in turn…..

18. Need to know more about sex differences in biology of CHD • Major risk factors for CHD similar in both groups but may affect them in different ways eg smoking worse for women? • Differences in symptoms especially pain • Hard to understand these as so many studies only include/report on men • Recent US study (1985-2001) showed only 32/272 systematic reviews and 25/55 RCT’s gave sex specific information (AHRQ 2004)

19. Failure to take gender seriously in explaining CHD • Most critics point out the lack of a female perspective but gender affects men too • Some of major CHD risk factors are shaped by gender eg smoking as well as diet and physical activity • Differences in illness behaviour: with CHD women less likely than men to seek help • After diagnosis, m/f patients likely to respond differently as do others: women get less support and rehab and often find adjustment harder

20. Gender bias in treatment of CHD? • Studies from US, UK have shown women may get less diagnostic testing than men with same symptoms (eg angiography) • Also less likely to be treated with heparin, aspirin or beta blockers or to get cardiac surgery • Causes of these differences are complex but seem to reflect in part the belief of health care workers that CHD is a ‘male problem’ • Is this ‘gender bias’ ? Need more research to see whether it is under-treatment of women or over-treatment of men

21. Putting sex/gender into CHD research • Both m/f need to be included in research and any differences identified and reported • Implications of differences need to be properly understood as biological and/or social • Eg why are women more likely than men to die within a year of myocardial infarction ? • Eg why were female civil servants in Whitehall study more likely to have elevated BP and therefore greater risk of CHD? (Steptoe and Willemsen 2004)

22. Conclusion: priorities for promotion of sex/gender sensitive research • Evaluation of existing biomedical knowledge base of different diseases to assess applicability to men/women • More research on social/gender dimensions of illness in both women and men • Deployment of both quant and qual methods sometimes in combination • Development of inter-disciplinary methodologies and collaboration to explore interconnections between sex/gender • Studies of links between sex/gender/health and other social stratifiers across a range of different settings • Recognition of sex/gender issues by medical educators, research funders , editorial boards and ethical reviewers in pursuit of good science as the basis for equitable/effective practice