Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Prevalence of the Use of Oral Contraceptives and Hormone Replacement Therapy in Japan: The Japan Nurses’ Health Study
Toshiyuki YasuiYuki IdenoHiromitsu ShinozakiYoshikazu KitaharaKazue NagaiKunihiko Hayashi
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JOURNALS OPEN ACCESS Advance online publication

Article ID: JE20200207

version.2: February 18, 2021
version.1: October 31, 2020

Background: There have been few community-based epidemiological studies in which the prevalence of exogenous hormone use, including the use of oral contraceptives (OCs) and hormone replacement therapy (HRT), has been accurately assessed in Japan.

Methods: We have been conducting repeated surveys of participants in the Japan Nurses’ Health Study (JNHS), as a nationwide prospective cohort study, since 2001. We determined the prevalence of exogenous hormone use at baseline and during a 10-year follow-up period. A total of 15,019 female nurses participated in the JNHS follow-up cohort. We determined the prevalence of OC use in 14,839 women <60 years of age at baseline and the prevalence of HRT use in 7,915 women, excluding premenopausal women, at the last time they answered a questionnaire. The duration of HRT use was estimated using the Kaplan-Meier method.

Results: Six percent of the participants used OCs. The proportion of HRT users who stopped HRT before the baseline survey, the proportion of women using HRT during the follow-up period, and the proportion of all of the participants who had used HRT were 3.2%, 10.6%, and 13.8%, respectively. The median duration of HRT use was 2 years.

Conclusions: The lifetime prevalences of exogenous hormone use during this prospective study conducted in Japanese nurses were 6.0% for OCs and 13.8% for HRT. The information obtained in this study will be useful for clarification of the association between exogenous estrogen exposure and estrogen-related diseases as future research.

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© 2020 Toshiyuki Yasui et al. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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