Sex, gender and the brain: Towards an inclusive research agenda

March 08, 2023


Sex, gender and the brain: Towards an inclusive research agenda

March 08, 2023

Emi Michael

Manager, Health Policy and Insights at Economist Impact

Emi is a Global Health Manager in the Health Policy and Insights team at Economist Impact. Emi is a global health equity specialist with a focus on the social determinants of health and has a wealth of experience in global health research, policy and programming. Her expertise in global health advisory, program design and healthcare communications means that Emi brings a breadth of experience to the team across technical areas. Her current role involves exploratory research using economic models, rapid reviews of scientific papers and the development of a global index on health inclusivity. Emi also designs and works on longer-term research assignments across the international development sphere, including related to Education and WASH. Emi has experience working across sectors, having held various roles across the health and social care industry, serving as a Health Inequalities Manager within the UK Department of Health and Social Care, Consultant Epidemiologist with the World Health Organisation under the Health Securities and Preparedness Division and as a Technical Delivery Officer with UNICEF. Emi has an undergraduate degree in Biomedical Science from the University of Warwick, a Master's in Public Health from Imperial College London and is currently completing a PhD in Health Equity at the University of Exeter.

Despite remarkable advances in science and technology, females are “missing” from brain research as it fails to capture and account for the differences in prevalence, severity and trajectory between men and women. Instead diagnostic approaches and innovative treatments are developed on the foundations of male dominated data and clinical research agendas. The consequences of this expand beyond poorer health outcomes in females and include wider economic consequences. Economist Impact conducted an in-depth research program exploring the role of sex and gender in brain disease outcomes to define the economic case for greater investment in sex and gender inclusive brain research.

The burden of death and disability from brain diseases is a global health challenge, costing over US$800bn in the United States (US) alone, exceeding that of cancer and cardiovascular disease. Brain disorders have been described as a pandemic far worse than Covid-19, with one in three people having some form of these conditions.

The level of risk, rate of progression, severity of disease and management approach for brain diseases are influenced by, among other factors, an individual’s sex, (denoted by characteristics that are biologically defined) and gender (denoted by socially constructed features). Yet, data detailing the influence of sex and gender on brain diseases are limited as these variables are rarely investigated or disaggregated. This gap in clinical research leads to inequitable service provision, from delayed diagnosis to inappropriate treatment and caregiving.

This Economist Impact white paper, informed by expert interviews, presents an economic impact framework to examine how sex and gender differences manifest across five brain diseases: Multiple Sclerosis, Stroke, Parkinson’s Disease, Alzheimer’s Disease and Migraine. The paper also explores the economic impact of proposed precipitating factors, consequences of differences in disease outcomes, and the most promising solutions to address the imbalance in research – which is, currently, primarily informed by clinical trial data dominated by male participation. This is the first phase of a research programme to create a modelling framework that quantifies the economic implications of sex and gender differences.

Key highlights from the report include:

  • Brain diseases are growing in prevalence, mirroring the global ageing population. One in three people worldwide live with a brain disease and the total number of people who have died from them has increased significantly over the last 30 years, costing US$1.7trn in the US and Europe.
  • Most brain diseases have a higher prevalence among females: Multiple Sclerosis is twice as common in females than males, Migraine is two to three times more common, and two-thirds of the Alzheimer’s Disease burden occurs among females. However, Parkinson’s Disease is more prevalent among males.
  • The economic impact of these conditions is shaped by factors including age of onset, promptness and accuracy of diagnosis, and the burden of caregiving. The human and economic cost calls for an increase in more inclusive and advanced scientific research.
  • Both sex and gender influence the prevalence, onset, and progression of brain diseases. Sex can modulate responses to treatment and disease progression, while gender influences factors such as communication between patients and healthcare providers, perceptions, stigma, and individual health-seeking behaviours.
  • The economic burden of brain diseases is vast, thereby paralysing global markets and stunting international development. The growing burden and longevity of brain disorders will economically impact individuals, their families and society for years to come. Symptoms can make maintaining a job difficult and often lead to both patients and caregivers, who are primarily women, having poor educational attainment as well as leaving the labour force. Tackling brain diseases therefore is not just a health problem, but also an economic one.
  • Females are ‘missing’ from science. They are under-represented in clinical trials and data are generally extrapolated and deemed suitable for all.                                               
  • Biases are persistent in clinical research but there are tools to reveal and overcome them. More inclusive clinical trial design, as well as the recruitment and inclusion of sex and gender sensitivity as a requirement for research funding are examples of tools that can be used to enable more inclusive brain research and policy agenda. More equitable preclinical and clinical research that tackle the biases that emerge from narrow trial populations would provide data to improve treatment protocols, adherence to drug regimens and overall disease outcomes.

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