Genetic epidemiology

Project descriptions

Here are a short description of some of our projects:

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1) Pregnancy characteristics and maternal cancer: A joint Nordic study

Project coordinator: Tone Bjørge
Funding: Nordic Cancer Union
Collaborators: Aarhus University Hospital (Denmark), Cancer Registry of Norway (Norway), Finnish Cancer Registry (Finland), National Cancer Institute (USA), National Institute for Health and Welfare (Finland), and Karolinska Institutet and Karolinska University Hospital (Sweden)


There has been an increased focus on pregnancy as a potential disease preventive or promoting phase of life. Growing evidence suggests an association between reproductive factors, obstetric events and long-term morbidity and mortality of mothers. Factors such as age at menarche (the first menstrual period) and menopause, parity (number of births), age at first birth, breastfeeding and use of exogenous hormones (oral contraceptives and postmenopausal hormone therapy) have been extensively studied in relation to maternal cancer risk. Pregnancy complications such as preeclampsia and gestational diabetes have also been explored. For some of these factors firm associations with specific cancers have been established whereas for others controversies still exist.

Aim and study design:

The general aim of this project is to explore relations between pregnancy conditions and birth characteristics and maternal cancer in a joint study that will pool linkages between birth and cancer registries in four Nordic countries (Denmark, Finland, Norway and Sweden). This data resource will include detailed information on the reproductive history of mothers and their subsequent cancer incidence.

The data will be analysed within a nested case-control design, which includes all breast, endometrial, ovarian and colorectal cancer cases in women who have had at least one registered pregnancy lasting more than 22 weeks, and 10 controls per case.

We believe our study will make a substantial contribution to the understanding of pregnancy as a cancer preventive or promoting phase of a woman’s life.


2) Cancer risk in families with children with birth defects

Project coordinator: Tone Bjørge
Funding: Norwegian Cancer Society
Collaborators: Aarhus University Hospital (Denmark), Cancer Registry of Norway (Norway), Finnish Cancer Registry (Finland), National Cancer Institute (USA), National Institute for Health and Welfare (Finland), and Karolinska Institutet and Karolinska University Hospital (Sweden)


Population-based studies have found an excess risk of cancer in children with birth defects. Cancer and birth defects may have a common aetiology (set of causes for the disease or condition). The aetiology may be genetic, environmental, or a combination. The rarity of both conditions, however, makes it challenging to study these associations. Very large cohorts are needed to include a sufficient number of children with malformations to allow estimates of cancer risk. In addition, the cohorts need to be monitored systematically several years after birth to follow the incidence of cancer.

In 2008, we conducted a large population-based cohort study on cancer risk in children with birth defects and in their parents and siblings, based on Norwegian and Swedish birth and cancer registry data. We observed an increased overall cancer risk in individuals with birth defects (SIR 1.7, 95% CI 1.6-1.9) that remained into early adulthood. The highest risks were seen in individuals with malformations in the nervous system, Down syndrome, and for those with multiple defects. No increased overall cancer risk, however, was observed among their parents and siblings, but mothers of Down syndrome children were at 23% (95% CI 4%-46%) increased risk to develop breast cancer.

Aim and study design:

In our previous study, we grouped the congenital malformations by organ system to increase power, and did not focus on specific malformations. We now aim at exploring these associations in further details in an updated and expanded data set with information from the birth, patient, cause of death and cancer registries in Denmark, Finland, Norway and Sweden. We want to examine the risk of specific cancers among individuals with specific birth defects, and also explore the cancer risk among their first-degree relatives.

This project will include two separate case-control studies: I) Cancer risk in children with birth defects and in their siblings, and II) Cancer risk in parents of children with birth defects. In the two case-control studies, 10 matched controls will be selected for each case.

In this project, we take advantage of large population-based registries in four Nordic countries to explore the relation between birth defects and cancer risk in more detail and more extensively than previously done. Whether birth defects are associated with cancer risk in the affected individual and their families is important for the understanding of the etiology of specific cancers, and could possibly allow for identification of individuals at elevated risk who would benefit from consequent clinical intervention.


3) Advancing knowledge of the metabolic syndrome and cancer risk (Me-Can 2.0)

Project coordinator: Tone Bjørge
Funding: Swedish Research Council
Collaborators: Innsbruck Medical University (Austria), Lund University (Sweden), Ulm University (Germany), and Umeå University (Sweden)


In the 80´s, the metabolic syndrome (MetS) was introduced to characterize the metabolic picture of patients at increased risk of cardiovascular diseases. Today several MetS definitions are in use, all including metabolic aberrations such as obesity, hyperglycemia, dyslipidemia, and hypertension.

In 2006, cohorts from Norway, Austria and Sweden were linked to national registers and were pooled in the Metabolic Syndrome and Cancer project (Me-Can project). Data from almost 600,000 men and women were used to study various MetS factors and a combined MetS score in relation to cancer risk. So far, more than 25 scientific papers have been published within Me-Can 1.0.

Aim and study design:

In Me-Can 2.0, we now aim to characterize the MetS-cancer relationship in more detail than previously done by adding new variables from cohort questionnaires and new register linkages, and new participants by linkages to national cancer and cause of death registers, and by implementing new statistical methods. The number of new cases in our studies will increase the statistical power substantially. Also, additional data will enable us to better control for potential confounders. Subprojects dealing with BMI/weight changes and cancer risk are to be coordinated by the Norwegian local working group.

We believe our studies will pinpoint important metabolic risk factors for cancer, and also provide important insight into preventive measures.

You can read more about the project at; http://me-can.se/