title: Existing data sources in clinical epidemiology: the Scandinavian Thrombosis and Cancer Cohort.
abstract: BACKGROUND
  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 cancer.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Clinical Medicine, KG Jebsen - Thrombosis Research and Expertise Center (TREC), UiT - The Arctic University of Norway ; Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Hilde
authors.initials: H
authors.lastname: Jensvoll
authors.affiliation: Department of Hematology, Aalborg University Hospital, Aalborg, Denmark ; Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Marianne T
authors.initials: MT
authors.lastname: Severinsen
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Jens
authors.initials: J
authors.lastname: Hammerstrøm
authors.affiliation: Department of Clinical Medicine, KG Jebsen - Thrombosis Research and Expertise Center (TREC), UiT - The Arctic University of Norway ; Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Sigrid K
authors.initials: SK
authors.lastname: Brækkan
authors.affiliation: Department of Clinical Medicine, Aalborg University, Aalborg, Denmark ; Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Søren R
authors.initials: SR
authors.lastname: Kristensen
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Suzanne C
authors.initials: SC
authors.lastname: Cannegieter
authors.affiliation: Department of Clinical Medicine, KG Jebsen - Thrombosis Research and Expertise Center (TREC), UiT - The Arctic University of Norway ; Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Kristine
authors.initials: K
authors.lastname: Blix
authors.affiliation: Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Tjønneland
authors.affiliation: Department of Clinical Medicine, KG Jebsen - Thrombosis Research and Expertise Center (TREC), UiT - The Arctic University of Norway ; Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands ; Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Frits R
authors.initials: FR
authors.lastname: Rosendaal
authors.affiliation: Department of Clinical Medicine, KG Jebsen - Thrombosis Research and Expertise Center (TREC), UiT - The Arctic University of Norway.
authors.forename: Olga
authors.initials: O
authors.lastname: Dziewiecka
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark ; Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Overvad
authors.affiliation: Department of Hematology, Trondheim University Hospital, Trondheim, Norway.
authors.forename: Inger Anne
authors.initials: IA
authors.lastname: Næss
authors.affiliation: Department of Clinical Medicine, KG Jebsen - Thrombosis Research and Expertise Center (TREC), UiT - The Arctic University of Norway ; Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway.
authors.forename: John-Bjarne
authors.initials: JB
authors.lastname: Hansen
keywords: cancer; incidence rates; person-years; population-based cohort; prospective; pulmonary embolism; venous thromboembolism