ESR1 and osteoarthritis: Before planning this study, we searched PubMed for articles published in English reporting cohort studies, observational or controlled studies, or randomised controlled trials relating to the effects of HRT agents in people with osteoarthritis, using the terms [“osteoarthritis” OR “hand osteoarthritis”] AND [“HRT” OR “Hormone” OR “Hormone Replacement Therapy”] OR [“estrogen” OR “oestrogen” OR “estradiol”] OR [“selective estrogen receptor modulator” OR “SERM”] from inception to Jan 1, 2016.