A Conceptual Model of Sex & Gender Influences on Health ...€¦ · internal factors external...
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A Conceptual Model of Sex & Gender Influences on Health and Disease orwh.od.nih.gov │#SABV │ @NIH_ORWH Chloe Bird, Ph.D. Special Advisor to the Director, ORWH 44 th Meeting of the NIH Advisory Committee on Research on Women’s Health September 13, 2017
Transcript of A Conceptual Model of Sex & Gender Influences on Health ...€¦ · internal factors external...
A Conceptual Model of Sex & Gender Influences on Health and Disease
orwh.od.nih.gov │#SABV │ @NIH_ORWH
Chloe Bird, Ph.D.Special Advisor to the Director, ORWH
44th Meeting of the NIH Advisory Committee on Research on Women’s Health
September 13, 2017
Presenter
Presentation Notes
Let’s talk about sex, gender, and health.
sex(biology)
XX/XYsex and gender
gender(social)
women/men
Presenter
Presentation Notes
When we study animals, it is simpler - the differences between males and females are sex differences; they are biological. When we study humans, there are sex differences AND there are also gender differences which are associated with the social and environmental contexts in which people live. Both sex and gender influence health. In some cases, we know that differences in health are biological in origin. These include cancers in sex-specific organs and sex-linked diseases, such as most forms of hemophilia, which are much more common in males than females. At the other end of the spectrum, there are likely some health conditions or events that we might be able to categorize as purely gendered, meaning entirely socially created and not biological. For example, we could discuss or debate whether some forms of violence against women are or are not solely social phenomenon – but we are not going to do that today. In most cases, when we study human health, we are studying sex AND gender, not sex OR gender. Because humans live in a world with a myriad of life-long gendered expectations and socialization, which overlay inherent biological differences. In fact, these have been shown to impact how we perceive and interact with newborns and infants based on their presumed sex. In the simplest case illustrated here, both sex and gender are treated as dichotomous. In reality, we recognize that there is more variation all the way down to the genetic level, which ORWH uses to define sex. Individuals who are intersexed (including those who are not XX or XY) and those who are transgender have additional complexity to their health and medical care. Similarly, some societies have recognized 3 or more genders, and those categories and related life experience likely shape health in complex ways as well. *****
internal factors
external factors
Influences on the Health of Women
the individual
organ systems
(Images: Wikimedia Commons; Pixabay, released under Creative Commons CC0; and National Institute of Environmental Health Sciences)
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To understand the influences of sex and gender on health, we need to consider the levels at which they operate – [click: L] internally from the genome to the individual and [click: R] externally from the individual to the national or even global social and environmental context. In short, internal biological factors AND external social and environmental factors and contexts shape our lives AND our health. [click: curved arrows] Almost all aspects of health are influenced by exposures to external and internal factors. [Click to advance to next slide, which looks the same: audience won’t see any change.] *****
internal factors
external factors
Influences on the Health of Women
the individual
life course
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Presentation Notes
These exposures occur across the life course and contribute to differences in health, such as the risk of diabetes, which is higher among girls, even prior to puberty, or rates of autism, which like heart disease, has been defined and understood as a disease of males and is now thought to include previously unrecognized expressions in females. Dr. Ching-Yi Shieh will be providing more information on trends in the disease burden in women and men right after our morning break. But first, let’s look at some specific examples where sex and gender play important roles in disease outcome and severity. *****
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social /environmental
context
biology
the individual
Bio-Social Interactions with Sex Influences on Lung Cancer
Walsh, D.C., Sorensen, G., Leonard, L. 1995. Gender, health, and cigarette smoking. Pp. 131-171 in Amick, B. III et al. (Eds.), Society and Health. New York: Oxford Univ. Press.
Zang, E.A., Wynder, E.L. 1996. Differences in lung cancer risk between men and women: examination of the evidence. Journal of the National Cancer Institute 88: 183-192.
Kiyohara, C., Ohno, Y. 2010. Sex diffs. in lung cancer susceptibility. Gend. Med. 7: 381-401.Bottorff, J.L. et al., 2014. Gender, smoking and tobacco reduction and cessation: a
scoping review. International Journal for Equity in Health 13: 114.Hiilamo, H., Crosbie, E., Glantz, S.A. 2014. The evolution of health warning labels on
cigarette packs. Tobacco Control 23: e2.(Images: Wikimedia Commons; and Ebony, June, 1977, Vol. 32, No. 8, fair use, no known copyright)
1 of 4 warnings since 1984: “SURGEON GENERAL’S WARNING: Smoking Causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy.”
1969-1984: “Warning: The Surgeon General Has Determined That Cigarette Smoking Is Dangerous to Your Health.”
Presenter
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Let’s start with lung cancer, the leading cause of cancer death in the U.S. Prohibitions against women smoking protected women from lung cancer for many decades. However, as these norms gave way, women’s smoking rates and eventually their lung cancer rates grew. After smoking was linked to cancer, smoking rates began to decline, but rates decreased more rapidly in men than women. Consequently, lung cancer rates peaked among men in 1984, but did not peak among women until 1998. Only after smoking rates declined did it become clear that women are at higher risk of lung cancer than men when they are not smokers. In fact, 20% of women with lung cancer are nonsmokers compared to less than 15% of men. [Click to advance allow references to slide in.] For decades, gendered social and behavioral patterns masked differences in men’s and women’s cancer risk among nonsmokers. [Click to advance to next slide.] *****
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Bio-Social Interactions with Sex Influences on Heart Disease
social /environmental
context
biology
the individualArtherosclerosis
Joakimsen, O. et al., 1999. Arterioscler. Thromb. Vasc. Biol. 19: 3007-3013.Bairey Merz, C.N. et al., 2006. J. Am. Coll. Cardiol. 47: S21-S29.Zhang, Z., Hayward, M.D. 2006. Journal of Marriage and Family 68: 639-657.McFarland, M.J., Hayward, M.D., Brown, D. 2013. Journal of Marriage and the Family 75:
363-380.Mathur, P. et al., 2015. Cardiovasc. Drugs Ther. 29: 319-327.Bots, S.H., Peters, S.A.E., Woodward, M. 2017. BMJ Glob Health 2: e000298. (Image: Wikimedia Commons)
(Images: Pixabay, released under Creative Commons CC0)
Presenter
Presentation Notes
Coronary heart disease is the leading cause of death and disability in the United States. Though rates of coronary heart disease are decreasing, they declined sooner and faster in men than women. We now know that biology influences men’s and women’s CVD risk. As Noel Bairey Merz has shown in her work on microvascular disease, which demonstrates that plaque accrues in the smallest vessels of the heart for women, whereas men have higher rates of developing acute blockages. In terms of social and environmental context, Mark Hayward and colleagues have shown strong gender differences in the relationship between marital biography and cardiovascular risk. You can think of this as exposure to being married over the adult life course. For example, Zhang and Hayward (2006) found that women who experienced marital loss had a higher CVD risk in midlife compared to continuously married women, whereas marital loss was not associated with men’s CVD risk. Emotional distress and socioeconomic status (SES) account for divorced women’s higher CVD risk. McFarland, Hayward, and Brown (2013) also found that marital exposure was protective of CVD risk for women but not men. They also found that early age at first marriage was associated with chronic inflammation among men but not women. Health behaviors did not explain these associations. [Click to allow the references to slide in.] As you can see, the influences of sex and gender are complex. [Click to advance to next slide, which looks the same: audience won’t see any change.] *****
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social /environmental
context
biology
Bio-Social Interactions with Sex Influences onAlzheimer’s Disease
the individual
Pinquart, M., Sörensen, S. 2006. J. Gerontol. B Psychol. Sci. Soc. Sci. 61: P33-P45.Qiu, C., Kivipelto, M., von Strauss, E. 2009. Dialogues Clin. Neurosci. 11: 111–128.Pöysti, M.M. et al., 2012. Int. J. Alzheimers Dis. 2012: 162960.Mielke, M.M., Vemuri, P., Rocca, W.A. 2014. Clin. Epidemiol. 6: 37-48.Mazure, C.M., Swendsen, J. 2016. The Lancet Neurology 15: 451-452.Van Cauwenberghe, C., Van Broeckhoven, C., Sleegers, K. 2016. Genet. Med. 18: 421-30.
(Image: Wikimedia Commons)
(Photo: The Lancet Neurology, April, 2016, Vol. 15)
normal aged brain Alzheimer’s patient’s brain
Presenter
Presentation Notes
Women’s lifetime risk of Alzheimer’s (1/6) is higher than their risk of breast cancer. Almost 2/3 of individuals diagnosed with AD are women, due in part to their greater longevity. Whether and to what extent women are otherwise at greater risk of AD compared to men remains unclear and the findings are mixed. Genetic research has found a growing number of genes and SNPs that increase risk and progression of AD in women but not men, and some with greater impact in men. Most but not all of the studies finding sex differences link the association to sex hormones, but not always in the expected directions. Thus, the biological mechanisms are not fully understood. Changing epidemiologic patterns for AD among women compared to men also appear to have been influenced by decades of changes in men’s and women’s comparative levels of education and their intellectual lifestyles and their physical activity patterns, all of which are protective against AD, as well as in their smoking behavior, which is associated with increased risk of AD in some studies (especially for men and in late life). [Click to allow references to slide in.] Of note, women are also more likely than men to be impacted by Alzheimer’s as unpaid family caregivers, and to lack a caregiver spouse due to a combination of longevity, gender roles and marriage patterns. [Click to advance to next slide.] *****
gendersex sex and gender
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[First click: words disappear. Second click: circles separate; labels reappear] As these examples have begun to illustrate, the influences of sex and gender on health are complex. They are not only additive, they can interact in ways that amplify or confound health effects. One’s sex can contribute to exposure to and the impact of social factors and contexts. For example, women’s greater longevity exposes them to greater risk of widowhood and poverty in old age, which in turn impact health. AND, this hazard is exacerbated by the social norms of marrying men who are on average 2 years older. Similarly, gendered social exposures can also influence exposure to or impact of biology factors on health. Consider the case of the impact of workplace childcare on men’s and women’s health. There are many reasons we might expect a stronger exposure and impact on women’s health, but for women workplace childcare can support extended breastfeeding and in so doing lower a woman’s risk of breast cancer. Workplace childcare will not have the same impact on men’s health. Consequently, understanding women’s health and the influence of sex and gender on health requires both a clear conceptual model encompassing both types of exposures and impacts, and rigorous methodology and research. *****
sex gender
exposure & health impact
exposure & health impact
Presenter
Presentation Notes
[First click: words disappear. Second click: circles separate; labels reappear] As these examples have begun to illustrate, the influences of sex and gender on health are complex. They are not only additive, they can interact in ways that amplify or confound health effects. One’s sex can contribute to exposure to and the impact of social factors and contexts. For example, women’s greater longevity exposes them to greater risk of widowhood and poverty in old age, which in turn impact health. AND, this hazard is exacerbated by the social norms of marrying men who are on average 2 years older. Similarly, gendered social exposures can also influence exposure to or impact of biology factors on health. Consider the case of the impact of workplace childcare on men’s and women’s health. There are many reasons we might expect a stronger exposure and impact on women’s health, but for women workplace childcare can support extended breastfeeding and in so doing lower a woman’s risk of breast cancer. Workplace childcare will not have the same impact on men’s health. Consequently, understanding women’s health and the influence of sex and gender on health requires both a clear conceptual model encompassing both types of exposures and impacts, and rigorous methodology and research. *****
Implications for Research
• The influences of sex and gender operate to some extent at every level of analysis.
• Controlling for the influences of sex and gender is insufficient.
• Recognizing where a body of research fits in the large model is critical.
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Presentation Notes
Given that the influences of sex and gender operate at every level from genetics and epigenetics to national and global contexts, failure to examine whether and to what extent male/female differences operate in our research, undermines not only the value of the research but the integrity of the models and of the findings. To only control statistically for sex/gender is likely in many cases to be model misspecification at the most basic level. Consequently, some researchers refer here to the fact that we are not a population of average people with one testicle and one ovary. Although some areas of research may examine solely biological or solely social or environmental influences on health, as we look to how specific research findings apply to individual and population health, it is important to consider how they fit into the larger model in which men’s and women’s health is influenced by both their sex and their gender. In so doing, we can identify potential interactions among social and biological factors and contexts. Drawing on this framework can help us make our work useful, by helping us to ask the right questions as we move our work from bench to bedside and bedside to community or population. *****
Special Thanks to the “Raising the Bar” Working Group
Chris BachrachWendy BaldwinJill BeckerWendy BrewsterVirginia CainWei-Jung ChenGeert DeVriesCarmen GreenKimberly Gregory
Mark HaywardPatricia HorohoRachel JonesAngela KashubaAna María LópezEmeran MayerCarolyn MazureNoel Bairey MerzSusan Newcomer
David PageAmy PallerMary PalmerJudy RegensteinerElizabeth SekineElizabeth SpencerMarcia StefanickConnie WeaverMichelle Williams
