Dive into the world of sex-disaggregated data with The George Institute’s Dr Sanne Peters
Can you tell us about your latest research as an epidemiologist working with sex-disaggregated data?
We have recently published two papers about sex differences in heart disease, the first concerned sex-specific trends in recurrent heart disease and the second compared the sex-specific rates of the second heart attack to those of a first attack. We also compared sex differences found in the results. In general, the perception is that women have a lower risk of heart disease than men, but there is very little evidence as to what happens after they survived the first heart attack. What we found was that women lose a considerable share of this natural advantage after they have had their first heart attack.
Has the COVID-19 pandemic prompted any learnings about the collection or use of sex-disaggregated data?
Very early on in the pandemic it became clear that there was a sex difference in the mortality rates of COVID-19. Once a man was diagnosed with COVID-19, they were more likely to die from it than a woman was. This really piqued the interest of those working in the sex and gender differences field. What we have found, through Global Health 50/50’s documentation on the availability of sex-disaggregated data on COVID-19, is that there are many gaps. Many countries do not collect specific data on the number of confirmed cases of COVID-19, and even fewer collect data on the number of women and men who die from COVID-19. There is also limited data on sex differences in exposure to COVID-19, which may well be worse in women. So, while sex differences is a hot topic owing to reported differences in mortality following COVID-19 infection, there are considerable gaps as countries and organisations who should be collecting this data are either not collecting or are not publishing it.
Why is sex-disaggregated health data not systematically collected?
The short answer is that, historically, it was thought that results obtained from predominantly male trials were also applicable to women. As women face hormonal fluctuations throughout their lives, their results were thought to cause some 'noise' in the results. A series of birth defects resulting from foetal exposure to certain drugs between the 1940s and 1970s also contributed to the exclusion of women and their foetuses, and later women of childbearing age, from clinical drug research. Nevertheless, it is now increasingly accepted that women are not just small men and that insights provided by sex-disaggregated data could lead to more tailored medicine and health recommendations to improve care and treatments for both women and men.
What is the biggest misunderstanding about the purpose of collecting and using sex-disaggregated data?
That it doesn’t matter (enough). Another prevalent misunderstanding that persists even today, is that you need to have large databases in order to provide such data. If you have a small database of 1,000 people, some may think that it is not as meaningful to disaggregate the data by sex. But, if the results from these 1,000 people are split by sex, you can still pool the data (with other relatively small-scale, accessible databases) and come up with quite a robust sex-specific answer.
What is the biggest challenge to pushing the sex-disaggregated data agenda?
I would say that there are two: lack of priority given to the subject, and cost.
On the first, some researchers may be mainly interested in the pure biological mechanisms and they may see diversity as 'softer’ science so they do not take it as seriously as I think it should be taken.
The second challenge concerns the cost of collecting data. In some cases, of course, the data does exist but if you wanted to test, for example, the effectiveness of the new COVID-19 vaccine and you wanted to do that by sex, you effectively need to double your sample size. With all the monetary and human costs involved with doing a trial like this, doubling the sample size would be really expensive. The other thing to consider is that whilst we are advocating for sex and gender aspects to be taken into consideration, there will be, rightly, other groups advocating for different racial or socioeconomic backgrounds, amongst others, to be equally represented in the data. So if you then included all of these groups the costs of such a study would be enormous.
How do you think we can best tackle this challenge?
Making sex-disaggregated analyses a mandatory requirement of funders or publishers will help us get some of the way there. However, if the motivation to change was intrinsic then that would be better. If we - as the sex and gender community - continue to advocate and show the importance of this data (through disaggregated results and policy effects) then people will start to follow.
Education will also play an important role. Currently, there is not much attention on sex and gender aspects in the medical curriculum and other health-related studies, so raising awareness on this very early in people’s education may change things as well.
What would you like to investigate next?
So far, we have identified sex differences in the field of heart disease and other conditions, but we don’t really know why they exist. So I think we really need to move beyond just identifying differences and start trying to explain them. Then we need to focus on moving them into health policies and clinical guidelines because that is, ultimately, how we change practice.
We also need to think about other conditions where sex and gender differences occur. Within the Institute’s Global Women’s Health programme we have looked at sex differences in cardiometabolic diseases, but have paid less attention to their appearance and manifestation in cancer, lung disease, and mental health disorders, so there are a lot of areas where we still need to start identifying those differences. We do not, however, need to do this ourselves. There are many cancer and mental health experts who have this data, so we just need to motivate and enthuse them to start looking at it from a sex and gender perspective.
Dr Sanne Peters is a Research Fellow in Epidemiology at The George Institute for Global Health, Senior Lecturer in the Faculty of Medicine at Imperial College London, and Chief Editor in Sex and Gender Differences in Disease for the Frontiers in Global Women's Health journal.