Dataset Information

Menopausal hormone therapy and breast cancer: what is the true size of the increased risk?

ABSTRACT:

Background

Menopausal hormone therapy (MHT) increases breast cancer risk; however, most cohort studies omit MHT use after enrolment and many infer menopausal age.

Methods

We used information from serial questionnaires from the UK Generations Study cohort to estimate hazard ratios (HRs) for breast cancer among post-menopausal women with known menopausal age, and examined biases induced when not updating data on MHT use and including women with inferred menopausal age.

Results

Among women recruited in 2003-2009, at 6 years of follow-up, 58?148 had reached menopause and 96% had completed a follow-up questionnaire. Among 39?183 women with known menopausal age, 775 developed breast cancer, and the HR in relation to current oestrogen plus progestogen MHT use (based on 52 current oestrogen plus progestogen MHT users in breast cancer cases) relative to those with no previous MHT use was 2.74 (95% confidence interval (CI): 2.05-3.65) for a median duration of 5.4 years of current use, reaching 3.27 (95% CI: 1.53-6.99) at 15+ years of use. The excess HR was underestimated by 53% if oestrogen plus progestogen MHT use was not updated after recruitment, 13% if women with uncertain menopausal age were included, and 59% if both applied. The HR for oestrogen-only MHT was not increased (HR=1.00; 95% CI: 0.66-1.54).

Conclusions

Lack of updating MHT status through follow-up and inclusion of women with inferred menopausal age is likely to result in substantial underestimation of the excess relative risks for oestrogen plus progestogen MHT use in studies with long follow-up, limited updating of exposures, and changing or short durations of use.

SUBMITTER: Jones ME

PROVIDER: S-EPMC4997554 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

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Publications

Menopausal hormone therapy and breast cancer: what is the true size of the increased risk?

Jones Michael E ME Schoemaker Minouk J MJ Wright Lauren L McFadden Emily E Griffin James J Thomas Dawn D Hemming Jane J Wright Karen K Ashworth Alan A Swerdlow Anthony J AJ

British journal of cancer 20160728 5

<h4>Background</h4>Menopausal hormone therapy (MHT) increases breast cancer risk; however, most cohort studies omit MHT use after enrolment and many infer menopausal age.<h4>Methods</h4>We used information from serial questionnaires from the UK Generations Study cohort to estimate hazard ratios (HRs) for breast cancer among post-menopausal women with known menopausal age, and examined biases induced when not updating data on MHT use and including women with inferred menopausal age.<h4>Results</h ...[more]

PMID: 27467055

Similar Datasets

Project description:BackgroundMenopausal hormone therapy (MHT) is a risk factor for breast cancer (BC). Evidence suggests that its effect on BC risk could be partly mediated by mammographic density. The aim of this study was to investigate the relationship between MHT, mammographic density and BC risk using data from a prospective study.MethodsWe used data from a case-control study nested within the French cohort E3N including 453 cases and 453 matched controls. Measures of mammographic density, history of MHT use during follow-up and information on potential confounders were available for all women. The association between MHT and mammographic density was evaluated by linear regression models. We applied mediation modelling techniques to estimate, under the hypothesis of a causal model, the proportion of the effect of MHT on BC risk mediated by percent mammographic density (PMD) for BC overall and by hormone receptor status.ResultsAmong MHT users, 4.2% used exclusively oestrogen alone compared with 68.3% who used exclusively oestrogens plus progestogens. Mammographic density was higher in current users (for a 60-year-old woman, mean PMD 33%; 95% CI 31 to 35%) than in past (29%; 27 to 31%) and never users (24%; 22 to 26%). No statistically significant association was observed between duration of MHT and mammographic density. In past MHT users, mammographic density was negatively associated with time since last use; values similar to those of never users were observed in women who had stopped MHT at least 8 years earlier. The odds ratio of BC for current versus never MHT users, adjusted for age, year of birth, menopausal status at baseline and BMI, was 1.67 (95% CI, 1.04 to 2.68). The proportion of effect mediated by PMD was 34% for any BC and became 48% when the correlation between BMI and PMD was accounted for. These effects were limited to hormone receptor-positive BC.ConclusionsOur results suggest that, under a causal model, nearly half of the effect of MHT on hormone receptor-positive BC risk is mediated by mammographic density, which appears to be modified by MHT for up to 8 years after MHT termination.

Dataset Information

Menopausal hormone therapy and breast cancer: what is the true size of the increased risk?

Background

Methods

Results

Conclusions

Publications

Menopausal hormone therapy and breast cancer: what is the true size of the increased risk?

Similar Datasets

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