TY - JOUR
T1 - Reproductive and menstrual factors and colorectal cancer incidence in the Women's Health Initiative Observational Study
AU - Murphy, Neil
AU - Xu, Linzhi
AU - Zervoudakis, Alice
AU - Xue, Xiaonan
AU - Kabat, Geoffrey
AU - Rohan, Thomas E.
AU - Wassertheil-Smoller, Sylvia
AU - O'Sullivan, Mary Jo
AU - Thomson, Cynthia
AU - Messina, Catherine
AU - Strickler, Howard D.
AU - Gunter, Marc J.
N1 - Publisher Copyright:
© 2017 Cancer Research UK. All rights reserved.
PY - 2017/1/3
Y1 - 2017/1/3
N2 - Background:Reproductive and menstrual factors have been evaluated as surrogates for long-term hormonal exposures in several prospective studies of colorectal cancer, yet findings have been conflicting.Methods:The relation of reproductive and menstrual factors (self-reported via a reproductive history questionnaire) with incident colorectal cancer was investigated among women enrolled in the Women's Health Initiative Observational Study (WHI-OS), a longitudinal cohort of 93 676 postmenopausal women (aged 50-79 years at enrolment) in which 1149 incident cases of colorectal cancer occurred over a median follow-up of 11.9 years. Multivariable Cox proportional hazards models that included established colorectal cancer risk factors were constructed to examine the association of colorectal cancer incidence with reproductive and menstrual factors.Results:Having had two children (vs nulliparous: hazard ratio (HR)=0.80, 95% confidence interval (CI): 0.64-0.99) was inversely associated with colorectal cancer risk. Compared with never users, ever use of oral contraceptives was associated with lower colorectal cancer risk (HR=0.74, 95% CI: 0.63-0.86); however, no relationship was observed for duration of oral contraceptives use (4 years vs 1 year: HR=0.94, 95% CI: 0.67-1.32). None of the remaining reproductive and menstrual factors was associated with colorectal cancer incidence.Conclusions:Parity and prior use of oral contraceptives were associated with lower colorectal cancer risk in this cohort of postmenopausal women.
AB - Background:Reproductive and menstrual factors have been evaluated as surrogates for long-term hormonal exposures in several prospective studies of colorectal cancer, yet findings have been conflicting.Methods:The relation of reproductive and menstrual factors (self-reported via a reproductive history questionnaire) with incident colorectal cancer was investigated among women enrolled in the Women's Health Initiative Observational Study (WHI-OS), a longitudinal cohort of 93 676 postmenopausal women (aged 50-79 years at enrolment) in which 1149 incident cases of colorectal cancer occurred over a median follow-up of 11.9 years. Multivariable Cox proportional hazards models that included established colorectal cancer risk factors were constructed to examine the association of colorectal cancer incidence with reproductive and menstrual factors.Results:Having had two children (vs nulliparous: hazard ratio (HR)=0.80, 95% confidence interval (CI): 0.64-0.99) was inversely associated with colorectal cancer risk. Compared with never users, ever use of oral contraceptives was associated with lower colorectal cancer risk (HR=0.74, 95% CI: 0.63-0.86); however, no relationship was observed for duration of oral contraceptives use (4 years vs 1 year: HR=0.94, 95% CI: 0.67-1.32). None of the remaining reproductive and menstrual factors was associated with colorectal cancer incidence.Conclusions:Parity and prior use of oral contraceptives were associated with lower colorectal cancer risk in this cohort of postmenopausal women.
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U2 - 10.1038/bjc.2016.345
DO - 10.1038/bjc.2016.345
M3 - Article
C2 - 27898658
AN - SCOPUS:85000786012
SN - 0007-0920
VL - 116
SP - 117
EP - 125
JO - British Journal of Cancer
JF - British Journal of Cancer
IS - 1
ER -