Characteristics of HRT users in Japan: Evidence from the Japan Nurses' Health Study

Objectives: Little is known about what type of women use hormone replacement therapy (HRT) in Japan. Based on the Japan Nurses' Health Study (JNHS), a large population cohort study, we determined the characteristics of HRT users by comparing the characteristics of new HRT users and the characteristics of women who did not use HRT during a 10-year follow-up period.Study design: Of the 15,019 JNHS participants, 4886 women reported an experience of menopausal transition during the 10-year follow-up period.Main outcome measurement: Characteristics of new HRT users.Results: The proportion of HRT users during the 10-year period was 8.5 %. Advanced age at menopause was significantly associated with a low rate of use of HRT. Past use of oral contraceptives, dysmenorrhea with disturbance in daily life and vasomotor symptoms were significantly associated with a high rate of use of HRT. The occupations of public health nurse and midwife and a history of bilateral oophorectomy were also signifi-cantly associated with a high rate of use of HRT.Conclusions: We determined the characteristics of new HRT users among middle-aged women during a 10-year follow-up period. Women who had sufficient knowledge about endocrinological hormones and women who had less reluctance to visit doctors for gynecological problems were likely to use HRT.