TY - JOUR
T1 - Colorectal cancer incidence and postmenopausal hormone use by type, recency, and duration in cancer prevention study II
AU - Hildebrand, Janet S.
AU - Jacobs, Eric J.
AU - Campbell, Peter T.
AU - McCullough, Marjorie L.
AU - Teras, Lauren R.
AU - Thun, Michael J.
AU - Gapstur, Susan M.
PY - 2009/11
Y1 - 2009/11
N2 - The Women's Health Initiative randomized trials showed a reduction in colorectal cancer risk with the use of estrogen plus progesterone (E + P), but not with estrogen alone (E-only), after intervention periods <7 years. Using data from the Cancer Prevention Study II Nutrition Cohort, we examined associations of colorectal cancer risk with E-only and E + P, including analyses by recency and duration of hormone use. During 13.2 years of follow-up, 776 cases of invasive colorectal cancer occurred among 67,412 postmenopausal women participants. Cox proportional hazards models were used to estimate multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI) of colorectal cancer for current and former hormone users according to hormone type and duration of use. Relative to women who never used postmenopausal hormones, current, but not former, use of E-only was associated with a reduced risk of colorectal cancer (RR 0.76; 95% CI, 0.59-0.97). Among current E-only users, duration of use was inversely and linearly associated with risk (P trend = 0.01). Use of E-only for <5 years was not associated with reduced risk, whereas use for ≥20 years was associated with a 45% reduction in risk (RR, 0.55; 95% CI, 0.36-0.86). There were no statistically significant associations between E + P and colorectal cancer risk. Our results suggest a strong inverse association of long-term use of E-only with colorectal cancer risk, underscoring the importance of collecting data on duration of hormone use in epidemiologic studies of postmenopausal hormones and risk of disease.
AB - The Women's Health Initiative randomized trials showed a reduction in colorectal cancer risk with the use of estrogen plus progesterone (E + P), but not with estrogen alone (E-only), after intervention periods <7 years. Using data from the Cancer Prevention Study II Nutrition Cohort, we examined associations of colorectal cancer risk with E-only and E + P, including analyses by recency and duration of hormone use. During 13.2 years of follow-up, 776 cases of invasive colorectal cancer occurred among 67,412 postmenopausal women participants. Cox proportional hazards models were used to estimate multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI) of colorectal cancer for current and former hormone users according to hormone type and duration of use. Relative to women who never used postmenopausal hormones, current, but not former, use of E-only was associated with a reduced risk of colorectal cancer (RR 0.76; 95% CI, 0.59-0.97). Among current E-only users, duration of use was inversely and linearly associated with risk (P trend = 0.01). Use of E-only for <5 years was not associated with reduced risk, whereas use for ≥20 years was associated with a 45% reduction in risk (RR, 0.55; 95% CI, 0.36-0.86). There were no statistically significant associations between E + P and colorectal cancer risk. Our results suggest a strong inverse association of long-term use of E-only with colorectal cancer risk, underscoring the importance of collecting data on duration of hormone use in epidemiologic studies of postmenopausal hormones and risk of disease.
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U2 - 10.1158/1055-9965.EPI-09-0596
DO - 10.1158/1055-9965.EPI-09-0596
M3 - Article
C2 - 19843681
AN - SCOPUS:72749109612
SN - 1055-9965
VL - 18
SP - 2835
EP - 2841
JO - Cancer Epidemiology Biomarkers and Prevention
JF - Cancer Epidemiology Biomarkers and Prevention
IS - 11
ER -