Hormone Replacement Therapy and Psoriasis Risk: A Nationwide Population-Based Cohort Study

Background: Hormone replacement therapy (HRT) is used to relieve menopause symptoms, but has been reported to be associated with coronary heart disease and cancers in women. However, a link between HRT and psoriasis has yet to be established. The aim of this study was to determine the association between HRT and the risk of psoriasis. Methods: We executed a nationwide population-based study. A total of 1,130,741 post-menopause women were enrolled in the national health care insurance database based on the enrollment criteria. The study population was classified into four groups based on the duration of the HRT, and the risk of psoriasis was analyzed. Results: The incidence rates of psoriasis per 1,000 person-years were 3.36 and 4.09 in the no history of HRT and ≥ 5 years of HRT, respectively. After adjustment for age, smoking, alcohol intake, regular exercise, body mass index, diabetes mellitus, hypertension, and dyslipidemia, the most prolonged duration of the HRT group (≥ 5 years) exhibited significantly increased risk of developing psoriasis (hazard ratio, 1.22; 95% confidence interval, 1.16–1.29). Conclusion: We propose that HRT in post-menopausal women is associated with an increased likelihood of psoriasis development.