Studying the sex differences in human health and disease

The genomicist Taru Tukiainen explores the poorly understood sex differences in human health and disease to improve current risk prediction models and to facilitate more accurate treatment and intervention. By directing attention to the role of sex, a topic often neglected in biomedical research, her research could lead to a higher degree of gender equality in the health sector.

It is a busy day at Biomedicum Helsinki, the Center for Medical Research and Training. As usual, the tall glass complex is buzzing with medical students, researchers, graduate students and staff members it hosts.

One of the researchers working in Biomedicum is the human genomicist Dr. Taru Tukiainen. The Helsinki-born specialist in sex differences in human health and disease has been an Academy of Finland funded researcher at the Institute for Molecular Medicine Finland FIMM since 2015.

With the Academy Research Fellow funding she recently received, Tukiainen is currently building her own research group to explore the biology underlying the male-female differences in disease risk and outcome for the next five years.

Listen to Taru Tukiainen talk about her research career

“Sex is thought to be just a confounder not necessarily the topic of interest”

One reason why Tukiainen’s research stands out is that sex has long been overlooked in health research. Although we know that diseases, drugs and treatments affect different sexes differently, for instance auto-immune diseases are often more prevalent in females, while others, such as cardiovascular diseases, are more common in males, the underlying reasons are poorly understood.

Despite being a crucial variable in determining risk and outcome of disease, sex is still often insufficiently taken into account in biomedical research.

“Sex is often thought to be just a confounder and not necessarily the topic of interest – so people just adjust the effect of sex away,” Tukiainen says.

On the other hand, it is partly the complexity of these male-female differences themselves that has contributed to the topic being neglected.

“Including both males and females in a study can be difficult: It is an awful thing to say, but pre-menopausal females can be a bit harder to study given the menstrual cycle and the effects that it has on the body,” Tukiainen says,

“So if we are studying some specific metabolic characteristics, the hormonal cycle might have a big role. That is of course disadvantage to the female sex as it may be that female metabolism, for instance, for some of the tested drugs is not sufficiently taken into account just by adjusting the dose for body weight”.

On a genomic level, one of the contributors to sex differences Tukiainen is particularly interested in are the sex chromosomes X and Y, which initially define us and every single cell in our body as male or female. The genetic research of human health and disease has, however, mostly focused on autosomes and studied the sex chromosomes much less.

“Maybe researchers got enough findings from the autosomes, so they did not bother looking into the sex chromosomes. Analysing sex chromosomes requires a bit more attention and time. The same models that are applied to autosomes do not necessarily work for the sex chromosomal data.”

“I try not to have any personal agenda”

By using genomics methods, tools and data, Tukiainen’s basic research is designed to explain the still poorly understood mechanisms with which sex impacts certain health characteristics. With her findings she hopes to contribute an additional layer to the current risk prediction models and facilitate more accurate medical treatment for each sex.

Tukiainen is aware that her research has a societal component because it can eventually contribute to improved sex-specific diagnostics and treatments and consequently to better gender equality in the healthcare sector. However, Tukiainen has ambivalent feelings about when her work gets framed in a political or even feminist way and prefers to leave the broader political interpretation of her findings to social science and gender studies.

“I am interested in the biology here and try not to have any personal agenda. I’m not saying that I am not a feminist or pro-gender equality in all areas of life – but as it is not my specialty, I do not think that I am the person to talk about these things in much detail.”

Sum of lucky coincidences

Tukiainen herself is a successful female scientist in the male-dominated field of computational genomics. She says that luck played a big role in her steep career path.

“It has been a sum of lucky coincidences actually. I never really had the aspiration to become a geneticist or genomicist.” 

Originally, Tukiainen came from a computational background. In her Master’s studies, however, she participated in a research group working on metabolomics and discovered her passion for working with medically-related questions. Finally, during her doctoral studies in computational system biology at Aalto University, she researched the genetic underpinnings of metabolomic traits by combining metabolite levels with genetic information – and got her first experience of human genetics.

“It got me even more excited and I started finding my own line of research in sex chromosomes and sex differences. And here we are!”

Tukiainen never felt discouraged about pursuing a research career in computational genetics and genomics by the high proportion of men in the field. If she compares herself to her mother, who is a scientist as well, she thinks that for women in research, times have changed for the better. Today, she even sees some benefits to being a female scientist.

“I really could not point to anything tangible that puts me in a disadvantaged position. It can be an asset, it can be a downside – sometimes I may stand out more easily than male researchers at the same career stage. Also, it may have been easier for me to choose this research topic without being labelled.”

“Finland is a great place to do genetic research”

Her research has enabled Tukiainen to attend conferences abroad and participate in several international collaborations – an aspect of her work that she highly appreciates.

“I do not necessarily have that many other people that are interested in the exact same topics and people that I can actively exchange research ideas with – in Finland at least. Internationally, of course there are a number of people who have similar ideas and interests.”

In 2013, Tukiainen had the opportunity to work as a postdoctoral research fellow at the Broad Institute of MIT, Harvard and the Massachusetts General Hospital. After three years, however, she returned to Finland. In the end, it was the high quality of life and the benefits of working in a Nordic welfare state that influenced her decision to return home.

“Working in Boston was an eye-opener in many ways. I still sometimes miss the enthusiasm and high-energy work environment of the Broad Institute. But there are also other things that matter in life besides work. In my view Finland and Helsinki offer me the best balance between the possibility to pursue my career interests in an exciting environment and to have a great quality of life.”

Here, in her hometown of Helsinki, Tukiainen likes to spend her free time with her family, friends and one year old Samoyed puppy Onni, with whom she walks outside in nature on a daily basis. In addition, she regularly takes singing classes and, occasionally, gets spontaneous gardening sprees.

The researcher also has special relationship to Indiana Jones movies – a remnant of her childhood: 

“I really, really liked Indiana Jones movies when I was a kid. Part of it was probably history and archeology, but it was more about finding new things, solving puzzles and going on an adventure. And that is partly what I do in my research: In my current work I am solving the mysteries of life, the mysteries of sex differences and hopefully making the world a better place one day.”

Need to make sure we have talented researchers of all ages in Finland

Tukiainen has built an impressive career and her story is a great example for young researchers. It shows that it pays off to follow your interests, even if that means changing your topic or field.

What has been the biggest challenge for her?

“One of the biggest challenges is definitely that there is just so much information, so many papers published every day, and I find it difficult to keep up with all the available literature.”

Even though Tukiainen has gained a firm foothold in the Finnish medical research community, she worries about the consequences current policies and budget cuts in the education and research sectors have for young striving researchers in Finland.

“I’m one of the lucky ones among young researchers: I got the funding to pursue my career here and therefore didn’t need to consider other options – a research career outside Finland or in industry – too much. It’s sad to see how so many bright young minds get frustrated with the lack of opportunities to stay and advance in academia in Finland and decide to go elsewhere where their input is more valued,” Tukiainen says.

“I hope we’ll see a change in the funding system soon enough to make sure we have the critical mass of talented researchers of all ages working towards meaningful goals here.”