Related Experiment Video
Updated: Aug 11, 2026

Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 16, 2010
Risk of breast cancer in relation to reproductive factors in Denmark
Abstract:
The effect of reproductive factors on breast cancer risk was evaluated in a population-based case-control study, including 1,486 breast cancer cases diagnosed over a one-year period in Denmark. They were identified from the files of the nationwide trial of the Danish Breast Cancer Co-operative group and the Danish Cancer Registry. The control group was an age-stratified random sample of 1,336 women from the general population. Data on risk factors were collected by self-administered (mailed) questionnaires. Significantly increased relative risks (RR) were associated with never being pregnant (RR = 1.47), an early terminated first pregnancy (RR = 1.43), and having a natural menopause after the age of 54 (RR = 1.67). Trends of decreasing risk were observed by increasing parity and age at menarche. These findings were independent of age at first full-term pregnancy which overall was not related to breast cancer risk, though a weak association appeared in women less than 50 years at diagnosis. The study confirmed that pregnancies must continue to term to offer protection against breast cancer.
More Related Videos
08:15gDNA Enrichment by a Transposase-based Technology for NGS Analysis of the Whole Sequence of BRCA1, BRCA2, and 9 Genes Involved in DNA Damage Repair
Published on: October 6, 2014
13:04In Vivo and Ex Vivo Approaches to Study Ovarian Cancer Metastatic Colonization of Milky Spot Structures in Peritoneal Adipose
Published on: October 14, 2015
Related Concept Videos
Cancer Prevention
Some...
Disorders of the Female Reproductive System
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Relative Risk
Odds Ratio
Hazard Ratio
For example, in a clinical trial evaluating a...