The relationship between using estrogen and/or progesterone and the risk of mammary gland hyperplasia in women: a meta-analysis

As reported that the usage of estrogen and/or progesterone increases the risk of mammary gland hyperplasia (MGH) with conflicting results. Therefore, we conducted a meta-analysis to higher elucidate the relationship between hormones and MGH. PubMed, Embase, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, and Wan-fang database were searched for studies until April 28, 2021. Nine related studies were included in the present meta-analysis. We found that the usage of estrogen and/or progesterone had a significant association with increasing the risk of MGH (RR = 1.56, 95% CI: 1.13–2.15, p = .000). The subgroup results showed that the risk of MGH increased in the Mix population (RR = 1.72, CI: 1.58–1.88, p < .001) but no significant difference in the Asian population. Meanwhile, as for using estrogen plus progesterone (EPP) and postmenopausal women the risk of MGH, respectively, increased (RR = 1.74, CI: 1.22–2.47, p = .002) and (RR = 1.75, CI: 1.24–2.47, p = .001) but no significant different for using estrogen alone and premenopausal women. This study findings indicated that using estrogen and/or progesterone might increase the risk of MGH in premenopausal and postmenopausal women.