How Blood Type Influences Risk of Venous Thrombosis

Formation of blood clots in the veins of the legs and lungs, also known as venous thromboembolism (VTE), is a common disease with severe complications including death. The ABO blood group system, which determines whether a person has blood type A, B, AB, or O, is not only important for blood transfusions but also plays a major role for VTE risk. Individuals with non-O blood types (A, B, or AB) have higher risk of venous thromboembolism (VTE) and 20-30% of the VTE events in the population are attributed to non-O blood types. While the association between ABO blood type and venous thrombosis is well-known, the biological mechanisms behind this association are not completely understood.

A recent study from the Thrombosis Research Group (TREC) at UiT - The Arctic University of Norway and University Hospital of North Norway, in collaboration with researchers from NTNU (Trondheim) and international researchers from France and USA, took a step toward unravelling these mechanisms. Using high-quality data from the Trøndelag Health Study (HUNT), we combined advanced protein measurements (proteomics) and genetic analyses (genomics) to investigate how the ABO blood group system influences VTE risk.

The study focused on a protein called histo–blood group ABO system transferase (BGAT), which is produced by the ABO gene. BGAT is a combined term for the enzymes that determines ABO blood type. These enzymes add the blood type antigens (A- and B-antigen) to red blood cells but also adds these antigens to other cells and proteins in the body. We found that plasma BGAT levels were strictly genetically regulated and that elevated BGAT levels were associated with an increased risk of VTE. The association between BGAT levels and VTE risk remained even after accounting for clotting-related factors in the blood which are already known to be affected by blood type.

Our research highlights the power of international collaboration and how the use of new technologies in unique population studies can explore how blood type affects disease risk. While this study provides new insights, it is just the first step in a broader effort to understand the complex relationship between the ABO system and VTE risk. Future research will build on these findings and methods to uncover hitherto unknown pathways through which blood type influences VTE risk, paving the way for improved prevention and treatment strategies for VTE.

The paper was recently published and was highlighted with a commentary in the world-leading journal in hematology Blood.

Reference: Onsaker AL, Arntzen AY, Trégouët DA, Nøst TH, Tang W, Guan W, Jonasson C, Morange PE, Hindberg KD, Folsom AR, Hveem K, Morelli VM, Hansen JB. Histo-blood group ABO system transferase plasma levels and risk of future venous thromboembolism: The HUNT Study. Blood. 2025

Evaluation of TREC by the Research Council of Norway

Evaluation of the Thrombosis Research group (TREC) by international experts commissioned by the Research Council of Norway (EvalMedHelse)

EvalMedHelse, or the Evaluation of Medical and Health Research in Norway, is a nationwide initiative designed to assess the quality, relevance, and societal impact of medical and health research conducted across Norwegian institutions during the years 2012-2022. Commissioned by the Research Council of Norway (RCN), international experts evaluated research institutions, departments and research groups with regards to organization, scientific and public dissemination, and contributions to their specific research fields. The evaluation was based on self-reports and available public information about the institutions, departments and research groups.

Recently, TREC, a translational research group focusing on the etiology of venous thromboembolism, received the evaluation report from EvalMedHelse 2023-2024. Overall, the research group got a high score, with marks of 4 or 5 on all items (5 is highest). The report highlighted that TREC is a successful and focused translational research group, that TREC during 25 years of research has gained a high international reputation, operating at a very high standard and achieved the position of international opinion leader with a large network of national and international collaborators.

TREC was evaluated as a very well-organized research group with strong leadership. The report further stated that “The research quality in relation to both contribution and leadership in research and outputs are excellent in the specific field of VTE”. “TREC has contributed to the reputation of the institution by substantial international visibility due to publications in high-ranked international peer-reviewed journals as well as many invited and selected oral presentations at important international conferences in the field (e.g., ISTH)”. With regards to societal impact, “TREC has contributed to increase academic competence of medical doctors at hospitals in Norway” and “taken a great focus on dissemination of project results and on increasing the public awareness and knowledge of VTE in the society”.

As a comment to the evaluation report, professor Hansen, the research group leader of TREC, states that “TREC is satisfied by the findings in the evaluation report, and we are encouraged to continue working to improve the organization as well as the scientific and societal relevance and impact of TREC. As the evaluation has been resource-demanding, and a huge effort for everyone involved, it will be exciting to see how the recommendations in the evaluation report will be implemented in the strategies and organization at the institutional- and department levels with goal to improve the framework for research in general and top research in particular”.

You can read the full report here: EvalMedHelse Report TREC

Body height and risk of blood clots in men versus women

Is body height a risk factor for venous thromboembolism (VTE) in both men and women, and do men have a higher risk of VTE because they are taller? 

Previous studies, including the Tromsø study, have shown a link between body height and risk of VTE in men, but studies in women have shown inconsistent results. Limited study size, and consequently few tall women included in these studies, could potentially explain this inconsistency. We therefore aimed to investigate the risk of VTE according to body height in men and women separately, in a large population-based study. Since men are on average taller than women, we also investigated whether differences in body height could explain differences in VTE risk between men and women in different age groups.

We used a merged cohort of 114,567 individuals from the Tromsø study and the Trøndelag Health Study (HUNT). The participants were followed up over a median of 22 years, and all VTE events during this period were recorded. We found that 10cm increase in body height on average increased the risk of VTE with 34% in men and 23% in women. The risk of VTE was higher in men than in women in the age group 50-74 years, but this difference disappeared after adjustment for differences in body height. In the young (19-49 years) and elderly (≥75 years) there was no difference in VTE risk in men versus women, but the risk was higher in women after adjusting for body height. Our findings indicate that body height mediates the risk of VTE to a larger extent in men than in women in all age groups.

The paper was published in Journal of Thrombosis and Haemostasis in May 2025. You can find the article here:

Arnesen et al. Body height and risk of venous thromboembolism in men vs women. JTH 2025.

John Bjarne Hansen  –  Professor

Sigrid Kufaas Brækkan  –  Professor

Omri Snir  –  Associate Professor

Thor Ueland  –  Professor II

Vania Maris Morelli  –  Researcher

Nadezhda Latysheva  –  Research technician

Kristian Dalsbø Hindberg  –  Researcher

Eduarda Mazagao Guerreiro  –  Researcher

Samantha Swamy  –  Doctoral Research Fellow

Maryam Hosseini  –  Doctoral Research Fellow

Christopher Antoun  –  Doctoral Research Fellow

Lisa Jakobsen  –  Doctoral Research Fellow

Celina Janene Cathro  –  Doctoral Research Fellow

Ellen-Sofie Wulff Eilertsen  –  Doctoral Research Fellow

Christabel Esi Damoah  –  Doctoral Research Fellow

Oda Gabrielle R. Leknessund  –  MD PhD student (Forskerlinja)

Vårin Eiriksdatter Wikan  –  MD PhD student (Forskerlinja)

Asbjørn Lund Onsaker  –  MD PhD student (Forskerlinja)

Nikolai Hagensen Eide  –  MD PhD student (Forskerlinja)

Camilla Langholm  –  MD PhD student (Forskerlinja)

Anna Yang Arntzen  –  MD PhD student (Forskerlinja)

Mathias Haugmo Storvand  –  MD PhD student (Forskerlinja)

Solveig Marie Valderhaug  –  MD PhD student (Forskerlinja)

Inga Røstvold  –  MD PhD student (Forskerlinja)