Using microdata to improve care for transgenders

/ Author: Masja de Ree/Miriam van der Sangen
How do hormone treatments impact transgenders’ health? This is the issue being explored by two medical researchers at Amsterdam’s VU University Medical Center (VUmc), Christel de Blok and Chantal Wiepjes. They are using microdata supplied by Statistics Netherlands (CBS) for the purposes of their study.

Gender dysphoria

VUmc’s Center of Expertise on Gender Dysphoria treats those suffering from gender dysphoria, which causes people with a female body to feel like men, or vice versa. The treatment involved can include hormone treatment. In the context of their PhD research, Christel de Blok and Chantal Wiepjes are studying the long-term health effects of this treatment.

Breast cancer

Ms De Blok is investigating the effects of hormone treatment on breast cancer. She is studying a large group of transgender subjects who registered with VUmc’s transgender department from 1972 to 2015. There are almost 7,000 people in this group. “By consulting the PALGA public pathology database (a national registry of pathology results) I was able to find out how many of these people developed breast cancer. However, if I was to accurately calculate the risk of breast cancer, I needed more data. I had to find out whether any of the subjects in our cohort had died and, if so, how old they were at the time of their death. Her search for this information led Christel de Blok to CBS. “At first CBS did not think they could help us, as the numbers involved would probably be too small.” CBS sets strict conditions for the use of data. In the case of small amounts of data, there is a risk that the analysis could be traced back to specific individuals. “But, when we said that our cohort consisted of almost 7,000 subjects, we were immediately able to make an appointment.”


In the course of the ensuing discussions, it appeared that CBS was able to provide the researchers with even more assistance. Ms Wiepjes points out that “CBS has details of the diagnoses and treatments (DTCs) that accident and emergency departments declare to health insurers, for example. My study is based on that data.” She explains that hormones such as oestrogen can affect bone density. “That is why the bone density of people undergoing hormone treatment is measured once every five years. However, we don’t know whether bone fractures actually occur more frequently in this group. Thanks to the data supplied by CBS, we can now look into this. CBS has data from extremely large groups. This means that our study’s conclusions are much more reliable than they would have been if we had conducted a survey among general practitioners, for example.”

Expanding the research area

The study of breast cancer in transgender individuals is almost complete, and the results are expected to be published this year. The study of fractures has only just started. How can these studies ultimately improve the quality of care? Ms De Blok notes that “The long-term effects of hormone treatment are still poorly understood. Our results can be used to provide people undergoing gender reassignment with reliable advice. For instance, do transgenders who have had their breasts removed still need to participate in the breast cancer screening programme, for example? And what about those who have instead developed breasts as part of the treatment? What risks do they run? And is the five-yearly bone density measurement actually necessary?”
During the microdata users’ afternoon, which was held on 12 April 2018 at CBS, Christel de Blok and Chantal Wiepjes gave a presentation about the issues they encountered in the course of their work. “We are keen to show fellow researchers the potential of CBS’s microdata. We started small, but we are already planning to expand our area of research!”

“The long-term effects of hormone treatment are still poorly understood”

Health and care

Anouk de Rijk, an account manager at CBS, attended the microdata users’ afternoon on 12 April. She presented a summary of the available microdata in the field of health and care. She noted that more and more people are now making use of this microdata. This is partly due to the growth in the number of files available and partly to improved accessibility. The data on this theme is derived both from surveys and from registries. “Health and care is very up-to-date. During the microdata day, we discussed the new data files that are now available for research and the impact of recent developments on this data. For example, there was a major healthcare reform in 2015. Some elements of care have been decentralised, shifting from the state to local authorities. In addition, the legislation in this area has also changed and this is impacting the way in which healthcare use is registered. Registries are a major source for microdata research, so these changes will also affect microdata files relating to the area of care. We wanted to explore that further during the microdata afternoon.”

A broader, more in-depth understanding

Ms De Rijk emphasises that access to CBS’ detailed microdata is only granted to authorised researchers, subject to strict conditions. Users can either access this material at CBS’ offices or from their own site, via a secure internet connection (remote access). Six hundred researchers throughout the world are currently using this remote access system for 350 different projects. “The files themselves are held on a server at CBS. The researchers can carry out analyses remotely, via a secure internet connection. The ability to link this CBS data to their own research results gives the users a broader, more in-depth understanding. But researchers will only get access to data that cannot be traced back to specific individuals, and CBS will always double check this if the data is to be published.”