Disparities in disease burden between males and females

Males and females have unique health concerns that grow over time. Females show higher rates of health loss from conditions including depressive disorders, anxiety, Alzheimer’s and other dementias. Males show higher rates of health loss from cardiovascular, respiratory, and liver diseases. 

The latest Global Burden of Disease Study (GBD) looks at trends across regions and age groups and highlights the need for specific strategies to address these challenges. We discuss the data with study authors IHME Researcher Gabriela Fernanda Gil and Dr. Vedavati Patwardhan of the University of California, San Diego.

This transcript has been lightly edited for clarity

Rhonda Stewart: Welcome to Global Health Insights, a podcast from IHME, the Institute for Health Metrics and Evaluation. I’m Rhonda Stewart. In this episode, we’ll hear from IHME researcher Gabriela Fernanda Gil and Dr. Vedavati Patwardhan of the University of California, San Diego, as they discuss differences across the lifespan in males and females in the top 20 causes of disease burden globally. The research is part of the Global Burden of Disease study, also known as GBD. GBD is the largest and most detailed scientific effort undertaken to quantify health trends. GBD provides a unique platform to compare the magnitude of diseases, injuries, and risk factors across groups, sexes, countries, regions, and time for decision-makers. GBD provides a unique way to compare countries’ health progress and to understand factors that impact health such as high blood pressure, cancer, heart disease, and many other causes. Led by IHME at the University of Washington, GBD is a truly global effort, with more than 11,000 researchers from over 160 countries and territories participating in the most recent update. The latest GBD studies are out now, so welcome to you both and let’s start by talking about some of the key findings of the study. Can you give us a brief overview of the research?

Dr. Vedavati Patwardhan: Yes. Thank you, Rhonda. So, in this study, we used data from the 2021 Global Burden of Disease study to examine differences in health between females and males. We focused on the 20 major causes of disease burden or health loss, and our analysis looks at these differences globally as well as by world regions, and covers females and males, spanning age ranges from adolescence to older ages. 

Overall, we found that males faced higher health loss, so in 2021, health loss, measured in terms of disability-adjusted life years, or DALYs, was higher in males than females for 13 out of the top 20 causes of disease. These conditions included COVID-19, road injuries, and a range of cardiovascular, respiratory, and liver diseases. Importantly, our study highlighted that females and males experience health and disease differently throughout their lifespan. 

Females bear a disproportionate toll from morbidity-driven conditions, that is, conditions whose impact predominantly contributes to disability throughout life as opposed to leading to death at younger ages. These include low back pain, depressive disorders, headache disorders, anxiety, other musculoskeletal disorders, Alzheimer’s disease and other dementias, as well as HIV/AIDS. On the other hand, males bear a higher health loss owing to mortality-driven conditions such as COVID-19, road injuries, and heart disease. We also found that many of these differences are present in age groups as young as 10–24-year-olds. Road injuries and mental health conditions stand out in particular as some of the causes with the greatest differences at younger ages and which persist as people age. 

And so, to sum up, our analyses show that there are persistent health differences between females and males, and these differences highlight the importance of taking into consideration the different health needs of females and males across the life course.

Rhonda Stewart: Okay, excellent. And what can you tell us about why these differences may exist? Of course there are differences between females and males. What did your research find in terms of some of the causes of these differences?

Researcher Gabriela Fernanda Gil: Yeah, so, as a descriptive study, we didn’t dive into many of the factors that drive these differences, but we know that a lot of the differences we observe are also reflected in the growing body of literature on how components of sex and gender influence health. 

So I particularly point folks toward a recent Lancet series exploring how restrictive gender norms can influence the well-being of individuals across different health outcomes, similar to the ones that we explored in our paper. We’re hoping to dive into these potential drivers a little bit more in the next phase of the research but really just focused on laying the landscape of what health differences exist at the moment.

Rhonda Stewart: And explain what DALYs are and why is that a useful measure to examine the differences between males and females across the lifespan?

Researcher Gabriela Fernanda Gil: Yeah, DALYs stands for disability-adjusted life years, and they are calculated as the sum of years lived with disability and years of life lost due to premature mortality. So, in other words, DALYs are a measure that captures both the duration and magnitude of health and life loss in a way that’s comparable across regions, ages, and time. 

We think that’s a really useful measure for drawing comparisons of health between females and males, because it captures both the morbidity and the mortality components of health, so what causes illness and what causes death, in a single measure. And as our findings highlight, focusing only on morbidity or only on mortality wouldn’t tell the full story of health gaps between females and males. So I think it really leverages or captures the full span of health loss.

Rhonda Stewart: Okay, great. So it sounds like DALYs are a good way to get a fuller picture of health loss.

Researcher Gabriela Fernanda Gil: Yeah, exactly.

Rhonda Stewart: Okay, great. And in addition to the differences that you found between males and females, were there particular differences that you found within age groups?

Dr. Vedavati Patwardhan: So, for many conditions, such as depressive disorders, anxiety disorders, and road injuries, we found that the differences between females and males began to emerge in adolescence, which is a critical time when gender norms, attitudes, and self-perceptions are shaped. In the case of conditions for which female DALYs were higher globally, we observed that the differences between females and males that begin early in life are sizable. 

So, for example, globally, for mental, neurological, and musculoskeletal disorders, there’s a substantial difference that disadvantages females in the age group of 10–24 years. So it emerges during this time and it further intensifies for those ages 25–49. And as for conditions where males have a higher disease burden, such as heart disease, lung cancer, or chronic kidney disease, the female-male differences tend to be smaller at younger ages, between 10 and 24 years, but widen over the life course. And I’d like to highlight here that road injuries are an exception to this global pattern. 

So younger males aged 10–24 years have a significantly higher burden of global DALY rates due to road injuries in all regions. And this is also the most notable cause of female-male differences that disadvantage males in this age group. This difference continues to widen between 25 and 49 years globally, but then diminishes at older ages. And, finally in our oldest age group of 70-plus years, for this age group, Alzheimer’s and other dementias are the leading conditions of excess disease burden for females.

Rhonda Stewart: As you said, this is a descriptive study. Some of the reasons why you see those differences in age groups aren’t included here. That's something you’ll explore in further research and future research.

Dr. Vedavati Patwardhan: Yes, exactly, we will hopefully be able to look at the drivers and determinants of these differences in future research.

Rhonda Stewart: Great. And tell us what you found with respect to global changes over time.

Researcher Gabriela Fernanda Gil: For the most part, we see gradual changes over time in the absolute difference between female and male DALY rates in our time period of 1990 through 2021. When we compared those 1990 rates to 2021 rates, we found that the gap between females and males grew slowly for depressive disorders, anxiety, other musculoskeletal disorders, and diabetes. And eight other conditions actually saw a decrease in the difference between females and males between 1990 and 2021. But three of those eight were actually driven by changes in the overall disease burden between those two years. So the relative difference between females and males actually increased. 

I think, overall, our takeaway when we looked over time was that overwhelmingly, even when progress was evident in closing the gap between females and males, we were struck by how gradual the observed changes were over the course of our 30-year time period, with the one exception of HIV and AIDS. We highlighted this a little bit in our paper because it shows a different temporal pattern to other causes. In 1990, there was no observed difference between HIV/AIDS DALY rates between males and females. But there was a sharp increase in rates that peaked in the early 2000s, and that sharp increase among females outpaced the increase observed in males, resulting in a large increase in DALY rates and DALY gaps between those two years. And then we see the difference quickly decrease from this peak, kind of following the pattern that we also see in sub-Saharan Africa. 

And so now we see pretty substantial progress being made toward closing the gap since the early 2000s, but still see higher rates of HIV/AIDS DALYs among females than among males in 2021.

Rhonda Stewart: Okay. And are there particular countries or regions that stood out in the results that you found?

Dr. Vedavati Patwardhan: Yes, we do find significant regional differences between females and males. For instance, for low back pain and musculoskeletal disorders, we found that the differences that disadvantaged females were particularly pronounced in South Asia and also in the Central Europe, Eastern Europe, and Central Asia regions. For HIV/AIDS, we found a very large difference that burdens females aged 25–49 in sub-Saharan Africa. 

This was the largest absolute difference across all regions and conditions for this age group, excluding COVID-19, of course. And sub-Saharan Africa is the only region where the DALY rate for HIV/AIDS is higher for females than for males in 2021. And the magnitude of this difference is so large that we basically see it reflected in the global patterns as well. Other regions that stood out, North Africa and the Middle East, have higher rates among females than males for diabetes, which is different because other regions had higher rates among males for diabetes. 

And then finally, for mental disorders, we found a higher burden for females compared to males across all regions for depressive and anxiety disorders. This difference was most pronounced in countries in the high-income regions, closely followed by Latin America and the Caribbean, and North Africa and the Middle East.

Rhonda Stewart: And let’s talk about the implications of the research. How can this information be put to use? You’ve both talked about some really specific differences between males and females, some interesting differences within the various age groups. And so, what are the implications here? How can people use this information?

Researcher Gabriela Fernanda Gil: Yeah, so I think a couple different ways. Our analysis really lays bare the need for granular insights on the health needs of males and females across ages, regions, and contexts. So, for example, all of the patterns that we’ve talked about in differences between females and males over ages highlights the need for early and targeted gender transformative interventions to prevent the onset and exacerbation of health conditions. And then the very existence of these differences and the patterns that we see speak to the need for concerted, sex-informed and gender-informed strategies that recognize the distinct health needs across different populations and different groups. 

Our insights can be more specifically leveraged to help inform health system planning. Moving forward, it’s clear that mental health conditions and musculoskeletal disorders, as examples, will persist as important causes of disease burden, particularly among females and aging populations. And we need to bolster funding research policies that address and recognize how these conditions, which disproportionately affect females, are pressing public health concerns globally, and especially in low- and middle-income countries. Less of a direct use of our results is that one of the biggest implications of our research is the clear need for more granular data on sex and gender identity. 

So our analysis was limited to females and males, and that’s something that we talk quite extensively about in the paper, given the constraints of our data. But even when comparing these groups, we saw clear distinctions between regions, between ages, and over time, and expanding sex and gender identity-disaggregated information, when possible and safe to do so, is crucial for better understanding these and other differences, as well as continuing to integrate a gender lens into the analysis of health data and health inequities, which is absolutely crucial for understanding and addressing barriers that sustain health inequities. So that’s kind of our big goal that the paper as a whole will be used to inform.

Rhonda Stewart: Wonderful. Well, thanks so much to you both. Details about the Global Burden of Disease study and a wide range of GBD-related resources can be found at healthdata.org. Thanks again.

Researcher Gabriela Fernanda Gil: Thank you so much.