Existing data sources in clinical epidemiology: the Scandinavian Thrombosis and Cancer Cohort

Hilde Jensvoll,1,2 Marianne T Severinsen,3,4 Jens Hammerstrøm,5 Sigrid K Brækkan,1,2 Søren R Kristensen,4,6 Suzanne C Cannegieter,7 Kristine Blix,1,2 Anne Tjønneland,8 Frits R Rosendaal,1,7,9 Olga Dziewiecka,1 Kim Overvad,10,11 Inger Anne Næss,12 John-Bjarne Hansen1,21Department of Clinical Medicine, KG Jebsen – Thrombosis Research and Expertise Center (TREC), UiT – The Arctic University of Norway, 2Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway; 3Department of Hematology, Aalborg University Hospital, 4Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; 5Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; 6Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark; 7Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands; 8Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark; 9Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, the Netherlands; 10Department of Cardiology, Aalborg University Hospital, Aalborg, 11Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus, Denmark; 12Department of Hematology, Trondheim University Hospital, Trondheim, NorwayBackground: Although venous thromboembolism (VTE) is a known common complication in cancer patients, there is limited knowledge on patient-related and cancer-specific risk factors in the general population. The Scandinavian Thrombosis and Cancer (STAC) Cohort was established by merging individual data from three large Scandinavian cohorts (The Tromsø Study, the second Nord-Trøndelag Health Study, and the Danish Diet, Cancer and Health Study). Here, we present the profile of the STAC cohort and provide age-specific incidence rates of VTE and cancerMethods: The STAC cohort includes 144,952 subjects aged 19–101 years without previous VTE or cancer. Baseline information collected in 1993–1997 included physical examination, self-administered questionnaires, and blood samples. Validated VTE events and cancer diagnoses were registered up to 2007–2012.Results: There were 2,444 VTE events (1.4 per 1,000 person-years [PY]) during follow-up, and the incidence increased exponentially from 0.3 per 1,000 PY in subjects aged 20–29 years to 6.4 per 1,000 PY in subjects aged 80+. Overall, 51% of the VTE events were provoked, and cancer was the most common provoking factor (19%), followed by immobilization and surgery (both 15%). In total, 19,757 subjects developed cancer during follow-up (9.8 per 1,000 PY), and the 5-year age-specific incidence rates of cancer were coherent with corresponding rates from the Norwegian Cancer Registry.Conclusion: The STAC cohort will provide a unique opportunity to explore the epidemiology and impact of genetic and environmental patient-related and cancer-specific risk factors for VTE in the general population.Keywords: venous thromboembolism, incidence rates, person-years, pulmonary embolism, population-based cohort, prospective, cancer