Out of all autoimmune diseases diagnosed, 80% are from women+*.
Our researcher, Grace Sear, investigates if this is solely due to physical differences or if other factors at play.
Autoimmune diseases are a class of illnesses that occur when the body's immune system mistakenly attacks its own healthy cells and tissues. There are over 80 different types of autoimmune diseases, including lupus, rheumatoid arthritis, multiple sclerosis (MS), and type 1 diabetes, and together they represent the third most common cause of chronic illness in first-world countries [1].
Research shows that women are up to three times more likely to develop autoimmune diseases than men. This gender gap exists across all age groups and ethnicities, affecting millions of women worldwide [2].
What may cause autoimmune diseases to be more prevalent in women?
There are likely multiple factors at play, including hormonal differences. A study found that throughout the second half of pregnancy when oestrogen hormones surge, women with MS experience a 70% reduction in relapses. As oestrogen levels drop after delivery, symptoms tend to return [3].
There is also some evidence to suggest that having two X chromosomes may be a predisposing factor, as another study found that mice with XX chromosomes develop autoimmune conditions such as lupus more frequently than XY mice, even when all the mice are engineered to have the same sex organs and hormones [4].
Environmental triggers such as infections, exposure to toxic chemicals, dietary components, gut dysbiosis, and smoking have been linked to a higher risk of autoimmune diseases in women [5-7].
So, we can appreciate that hormones, genetics and toxins play a role in this gender disparity, but these only account for a partial cause in autoimmune disease development in women [5].
Everyday lives can take a toll
Today’s generation of women tend to experience higher levels of stress than men, often due to societal expectations and responsibilities, such as caring for children and aging parents, while maintaining a career. Research shows women may also be more likely to internalise stress, maintaining the ‘everything is fine’ mentality, which can lead to chronic inflammation and immune dysfunction [8-11].
It has been found chronic stress can alter the biology of our cells, and even trigger and exacerbate autoimmune diseases. For example, exposure to chronic stress has been shown to reduce the number and function of glucocorticoid receptors on immune cells, reducing their response to cortisol’s (stress hormone) regulatory control. According to the glucocorticoid resistance hypothesis, an increased concentration of cortisol levels as a response to long-term stress, can induce a down-regulation of glucocorticoid receptors (e.g. reduction in number, binding capacity, and affinity) in immune system cells, thus increasing the risk of inflammation [12].
Another study of over 120,000 people (tracked over 5 years), shows that those who had experienced Post Traumatic Stress Disorder (PTSD) were at a 58% higher risk of developing certain autoimmune diseases compared to those without PTSD. Even when considering factors like BMI, smoking, and alcohol use, this risk remained largely the same [10].
If we look back at earlier generations, we can appreciate the different pressures and stress experienced by women in our modern, Western world. A study from 2000 that compared the daily experiences of women in the 1990s to those of women in the 1930s found that women in the 90s reported significantly more time pressures and a higher frequency of work-family conflicts. Additionally, these women reported feeling more rushed and less able to enjoy their leisure time than women living 60 years prior [13].
Over the years, women have taken on more work (and hence more stress!) on top of their innate caregiving responsibilities.
Advocating for Holistic Research and Comprehensive Care
While it's important to acknowledge that autoimmune diseases can affect people of all genders, the striking prevalence gender gap and the societal burden placed on women to absorb stress raise a critical question: Is autoimmune disease evolving into a women's health crisis? In a prior blog post, we explored the gender gap in healthcare systems, designed primarily around cisgendered men. As we navigate the intricate landscape of autoimmune diseases and their disproportionate impact on women, we uncover multiple contributing factors, such as hormonal variations and environmental triggers. Yet, our research reveals an often-overlooked element in this puzzle - the profound influence of relentless modern-life stress on women's health. This prompts us to consider whether societal expectations, the dual roles women often assume as caregivers, and chronic stress are directly linked to the rise in autoimmune diseases among women.
To create meaningful change, there must be a holistic approach in autoimmune disease research and healthcare. It's not just about examining the physical aspects; we need to explore the wider picture. In advocating for holistic research and comprehensive care, we aim to bridge the gap between understanding and action, shaping marketing strategies that resonate with the unique challenges faced by women in our modern world. Autoimmune diseases are a shared concern, and by unravelling their complexities, we can better support and empower women in their journey to health and well-being.
* Women+ is a term coined by Rock Health to encompass the health needs of cisgender women, transgender or nonbinary individuals whose health needs relate to those of cisgender women
References
1. Hayter SM, Cook MC. Updated assessment of the prevalence, spectrum and case definition of autoimmune disease. Autoimmun Rev 2012;11:754–765. 2. Desai, M. K., & Brinton, R. D. (2019). Autoimmune disease in women: endocrine transition and risk across the lifespan. Frontiers in endocrinology, 10, 265. 3. Voskuhl, R. & Momtazee, C. Neurotherapeutics 14, 974–984 (2017). 4. Laffont, S. & Guéry, J.-C. Adv. Immunol. 142, 35–64 (2019). 5. Jörg, S., Grohme, D. A., Erzler, M., Binsfeld, M., Haghikia, A., Müller, D. N., … & Kleinewietfeld, M. (2016). Environmental factors in autoimmune diseases and their role in multiple sclerosis. Cellular and Molecular Life Sciences, 73, 4611-4622. 6. Khan, M. F., & Wang, H. (2020). Environmental exposures and autoimmune diseases: contribution of gut microbiome. Frontiers in immunology, 10, 3094. 7. Vojdani, A. (2014). A potential link between environmental triggers and autoimmunity. Autoimmune diseases, 2014. 8. Cohen, S., Janicki-Deverts, D., Doyle, W. J., Miller, G. E., Frank, E., Rabin, B. S., & Turner, R. B. (2012). Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proceedings of the National Academy of Sciences, 109(16), 5995-5999. 9. Silverman, M. N., Pearce, B. D., Biron, C. A., & Miller, A. H. (2005). Immune modulation of the hypothalamic-pituitary-adrenal (HPA) axis during viral infection. Viral immunology, 18(1), 41-78. 10. Bookwalter, D. B., Roenfeldt, K. A., LeardMann, C. A., Kong, S. Y., Riddle, M. S., & Rull, R. P. (2020). Posttraumatic stress disorder and risk of selected autoimmune diseases among US military personnel. BMC psychiatry, 20(1), 1-8. 11. Bergdahl & Bergdahl, 2002; Gao et al, 2019). 12. Cohen, S., Janicki-Deverts, D., Doyle, W. J., Miller, G. E., Frank, E., Rabin, B. S., & Turner, R. B. (2012). Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proceedings of the National Academy of Sciences, 109(16), 5995-5999. 13. Bianchi, S. M., Milkie, M. A., Sayer, L. C., & Robinson, J. P. (2000). Is anyone doing the housework? Trends in the gender division of household labor. Social Forces, 79(1), 191-228.