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The relationship between gravidity and parity to colorectal cancer risk

Wernli , Karen J. and Wang , Yinghui and Zheng , Yingye and Potter , John D. and Newcomb , Polly A. (2009) The relationship between gravidity and parity to colorectal cancer risk. Journal of Women's Health, 18 (7). pp. 995-1001. ISSN 1540-9996

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Objectives: The influence of hormonal changes due to pregnancy has been well-studied in relation to colorectal cancer risk, but the association remains undefined. The purpose of this investigation was to examine the relationship between differences in gravidity and parity, and colorectal cancer risk, and whether the association varied by microsatellite instability (MSI), a feature more common in women, in a case-control study. Methods: The study population included incident colorectal cancer cases (n=1,014), aged 50-74 years, diagnosed from 1998-2002 in Washington state and controls (n=1,064) randomly selected from population lists. All study subjects completed telephone interviews to ascertain prior pregnancies and live births, and other covariates. Case tissue samples were obtained for MSI analyses. Multivariable logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI), adjusting for age, family history of colorectal cancer, body mass index, education, endoscopy screening, oral contraceptive use, hormone therapy use, smoking, and alcohol consumption. Results: There was an approximate 30-50% reduction in risk of colon cancer associated with gravidity, which was attenuated in the analysis with parity. Increasing gravidity and parity were associated with a suggestion of a decreasing trend in risk for rectal cancer (p-trend=0.07). Compared to women who had equal numbers of pregnancies to livebirths, women who were nulligravid and nulliparous had 40-60% increased risk of colon cancer. There was a suggestion of a reduced risk of both colon and rectal cancer associated with one more pregnancy than live birth. There was a suggestion of an increased risk of MSI-high tumors with nulligravidity and nulliparity. Conclusions: These results confirm the importance of pregnancy events in the etiology of colon and rectal cancer.

Item Type: Article or Abstract
DOI: 10.1089/jwh.2008.1068
PubMed ID: 19575687
PMCID: PMC2851134
Grant Numbers: R01CA 76366, UO1CA74794
Subjects: Diseases > Solid tumors > Digestive system cancer
Cellular and Organismal Processes > Genetic processes > Genomic instability
Molecules > Hormones
Research Methodologies > Epidemiology > Risk assessment
Cellular and Organismal Processes > Reproduction
Depositing User: Library Staff
Date Deposited: 16 Apr 2010 18:34
Last Modified: 14 Feb 2012 14:42

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