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The Tromsø Mammography and Breast Cancer Study

Breast cancer is the most commonly occurring malignancy among Norwegian women. The incidence of breast cancer varies a lot around the world. This variation is an indicator that breast cancer is a preventable disease, and that lifestyle and environment factors affect the risk of breast cancer.


How a breast appears on an x-ray image (mammogram) varies by how much fatty tissue, connective tissue, and epithelial tissue there is in the breast. Epithelial and connective breast tissues are radiodense and will appear light on a mammogram, while fatty breast tissue is radiolucent and will appear dark. A mammogram can be classified according to parenchymal patterns (the original method) and percent mammographic density (the newer method).

Mammographic density – a strong risk factor for breast cancer
Epidemiological studies have shown that mammographic parenchymal patterns and mammographic density are independent risk factors for breast cancer. Apart from age and some genetic mutations, mammographic density is regarded as one of the strongest breast cancer risk factors.

Read more about:
- Study group
- Ethics
- International collaborators
- National collaborators
- Financial support
- Publications
- PhD thesis/Doctoral thesis

We wish to study the associations between lifestyle factors, diet, hormonal therapy, endogenous hormones, genetics, biological markers and mammographic parenchymal patterns / mammographic density.

Data collection
In 2001 the Tromsø Mammography and Breast Cancer (TMBC) study was initiated at the Institute of Community Medicine, University of Tromsø. Postmenopausal women, age 55 and over, residing in the municipality of Tromsø, Norway, and attending the population-based Norwegian Breast Cancer Screening Program (NBCSP) at the University Hospital of North Norway (UNN) were eligible for the study. During spring of 2001 and 2002, altogether 1,041 women were included in the TMBC study. After the women had undergone their NBCSP screening mammograms, they were interviewed by a nurse from the Department of Clinical Research, UNN, about reproductive and menstrual factors, previous history of cancer, smoking status, and use of HT or other medications. The participants had their height and weight measured, blood samples drawn, and each was given a questionnaire to be completed at home, and returned in a prepaid envelope.

Page administrator: Inger Torhild Gram
Last updated: 02.02.2016 14:55