Oral contraceptive use, hormone replacement therapy, reproductive history and risk of colorectal cancer in women

Geoffrey C. Kabat, Anthony B. Miller, Thomas E. Rohan

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Evidence from epidemiologic studies suggests a possible role of exogenous and endogenous hormones in colorectal carcinogenesis in women. However, with respect to exogenous hormones, in contrast to hormone replacement therapy, few cohort studies have examined oral contraceptive use in relation to colorectal cancer risk. We used data from a large cohort study of Canadian women enrolled in a randomized controlled trial of breast cancer screening to assess the association of oral contraceptive use, hormone replacement therapy and reproductive factors with risk of colorectal cancer, overall and by subsite within the colorectum. Cancer incidence and mortality were ascertained by linkage to national databases. Among 89,835 women aged 40-59 at enrollment and followed for an average of 16.4 years, we identified 1,142 incident colorectal cancer cases. Proportional hazards models were used to estimate the associations between the exposures of interest and risk of colorectal cancer. Ever use of oral contraceptives at baseline was associated with a modest reduction in the risk of colorectal cancer (hazard ratio 0.83, 95% confidence interval 0.73-0.94), with similar effects for different subsites within the colorectum. No trend was seen in the hazard ratios with increasing duration of oral contraceptive use. No associations were seen with use of hormone replacement therapy (ever use or duration of use) or reproductive factors. Our results are suggestive of an inverse association between oral contraceptive use and colorectal carcinogenesis. However, given the lack of a dose-response relationship and the potential for confounding, studies with more complete assessment of exogenous hormone use throughout the life course are needed to clarify this association.

Original languageEnglish (US)
Pages (from-to)643-646
Number of pages4
JournalInternational Journal of Cancer
Volume122
Issue number3
DOIs
StatePublished - Feb 1 2008

Fingerprint

Reproductive History
Hormone Replacement Therapy
Oral Contraceptives
Colorectal Neoplasms
Hormones
Carcinogenesis
Cohort Studies
Risk Reduction Behavior
Early Detection of Cancer
Proportional Hazards Models
Epidemiologic Studies
Randomized Controlled Trials
Databases
Confidence Intervals
Breast Neoplasms
Mortality
Incidence
Neoplasms

Keywords

  • Cohort study
  • Colorectal neoplasms
  • Hormone replacement therapy
  • Oral contraceptive use
  • Reproductive factors

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Oral contraceptive use, hormone replacement therapy, reproductive history and risk of colorectal cancer in women. / Kabat, Geoffrey C.; Miller, Anthony B.; Rohan, Thomas E.

In: International Journal of Cancer, Vol. 122, No. 3, 01.02.2008, p. 643-646.

Research output: Contribution to journalArticle

@article{890f2b714a1947808aa76317c90138ad,
title = "Oral contraceptive use, hormone replacement therapy, reproductive history and risk of colorectal cancer in women",
abstract = "Evidence from epidemiologic studies suggests a possible role of exogenous and endogenous hormones in colorectal carcinogenesis in women. However, with respect to exogenous hormones, in contrast to hormone replacement therapy, few cohort studies have examined oral contraceptive use in relation to colorectal cancer risk. We used data from a large cohort study of Canadian women enrolled in a randomized controlled trial of breast cancer screening to assess the association of oral contraceptive use, hormone replacement therapy and reproductive factors with risk of colorectal cancer, overall and by subsite within the colorectum. Cancer incidence and mortality were ascertained by linkage to national databases. Among 89,835 women aged 40-59 at enrollment and followed for an average of 16.4 years, we identified 1,142 incident colorectal cancer cases. Proportional hazards models were used to estimate the associations between the exposures of interest and risk of colorectal cancer. Ever use of oral contraceptives at baseline was associated with a modest reduction in the risk of colorectal cancer (hazard ratio 0.83, 95{\%} confidence interval 0.73-0.94), with similar effects for different subsites within the colorectum. No trend was seen in the hazard ratios with increasing duration of oral contraceptive use. No associations were seen with use of hormone replacement therapy (ever use or duration of use) or reproductive factors. Our results are suggestive of an inverse association between oral contraceptive use and colorectal carcinogenesis. However, given the lack of a dose-response relationship and the potential for confounding, studies with more complete assessment of exogenous hormone use throughout the life course are needed to clarify this association.",
keywords = "Cohort study, Colorectal neoplasms, Hormone replacement therapy, Oral contraceptive use, Reproductive factors",
author = "Kabat, {Geoffrey C.} and Miller, {Anthony B.} and Rohan, {Thomas E.}",
year = "2008",
month = "2",
day = "1",
doi = "10.1002/ijc.23079",
language = "English (US)",
volume = "122",
pages = "643--646",
journal = "International Journal of Cancer",
issn = "0020-7136",
publisher = "Wiley-Liss Inc.",
number = "3",

}

TY - JOUR

T1 - Oral contraceptive use, hormone replacement therapy, reproductive history and risk of colorectal cancer in women

AU - Kabat, Geoffrey C.

AU - Miller, Anthony B.

AU - Rohan, Thomas E.

PY - 2008/2/1

Y1 - 2008/2/1

N2 - Evidence from epidemiologic studies suggests a possible role of exogenous and endogenous hormones in colorectal carcinogenesis in women. However, with respect to exogenous hormones, in contrast to hormone replacement therapy, few cohort studies have examined oral contraceptive use in relation to colorectal cancer risk. We used data from a large cohort study of Canadian women enrolled in a randomized controlled trial of breast cancer screening to assess the association of oral contraceptive use, hormone replacement therapy and reproductive factors with risk of colorectal cancer, overall and by subsite within the colorectum. Cancer incidence and mortality were ascertained by linkage to national databases. Among 89,835 women aged 40-59 at enrollment and followed for an average of 16.4 years, we identified 1,142 incident colorectal cancer cases. Proportional hazards models were used to estimate the associations between the exposures of interest and risk of colorectal cancer. Ever use of oral contraceptives at baseline was associated with a modest reduction in the risk of colorectal cancer (hazard ratio 0.83, 95% confidence interval 0.73-0.94), with similar effects for different subsites within the colorectum. No trend was seen in the hazard ratios with increasing duration of oral contraceptive use. No associations were seen with use of hormone replacement therapy (ever use or duration of use) or reproductive factors. Our results are suggestive of an inverse association between oral contraceptive use and colorectal carcinogenesis. However, given the lack of a dose-response relationship and the potential for confounding, studies with more complete assessment of exogenous hormone use throughout the life course are needed to clarify this association.

AB - Evidence from epidemiologic studies suggests a possible role of exogenous and endogenous hormones in colorectal carcinogenesis in women. However, with respect to exogenous hormones, in contrast to hormone replacement therapy, few cohort studies have examined oral contraceptive use in relation to colorectal cancer risk. We used data from a large cohort study of Canadian women enrolled in a randomized controlled trial of breast cancer screening to assess the association of oral contraceptive use, hormone replacement therapy and reproductive factors with risk of colorectal cancer, overall and by subsite within the colorectum. Cancer incidence and mortality were ascertained by linkage to national databases. Among 89,835 women aged 40-59 at enrollment and followed for an average of 16.4 years, we identified 1,142 incident colorectal cancer cases. Proportional hazards models were used to estimate the associations between the exposures of interest and risk of colorectal cancer. Ever use of oral contraceptives at baseline was associated with a modest reduction in the risk of colorectal cancer (hazard ratio 0.83, 95% confidence interval 0.73-0.94), with similar effects for different subsites within the colorectum. No trend was seen in the hazard ratios with increasing duration of oral contraceptive use. No associations were seen with use of hormone replacement therapy (ever use or duration of use) or reproductive factors. Our results are suggestive of an inverse association between oral contraceptive use and colorectal carcinogenesis. However, given the lack of a dose-response relationship and the potential for confounding, studies with more complete assessment of exogenous hormone use throughout the life course are needed to clarify this association.

KW - Cohort study

KW - Colorectal neoplasms

KW - Hormone replacement therapy

KW - Oral contraceptive use

KW - Reproductive factors

UR - http://www.scopus.com/inward/record.url?scp=37349089395&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=37349089395&partnerID=8YFLogxK

U2 - 10.1002/ijc.23079

DO - 10.1002/ijc.23079

M3 - Article

C2 - 17847020

AN - SCOPUS:37349089395

VL - 122

SP - 643

EP - 646

JO - International Journal of Cancer

JF - International Journal of Cancer

SN - 0020-7136

IS - 3

ER -