Hormones, supplements, and stones: A systematic review of urolithiasis risk in postmenopausal women – An EAU endourology study

Background Kidney stones are becoming increasingly common in postmenopausal women, driven by hormonal changes, aging, and lifestyle factors, with oestrogen deficiency affecting calcium metabolism and urinary composition. This review explores how hormone replacement therapy, as well as calcium and vitamin D supplementation, may influence the risk of kidney stones in this population.Methods A systematic literature search was conducted in PubMed, Scopus, and EMBASE. Studies were screened according to PRISMA 2020 guidelines and PICO criteria. Fifteen studies, including randomized trials, observational cohorts, and case – control studies, were included, encompassing 150,341 postmenopausal women. Data on hormone replacement therapy, supplementation, urinary parameters, and stone incidence were extracted and synthesized.Results The relationship between hormone replacement therapy and kidney stone risk remains unclear. Oestrogen, however, seems to promote higher urinary citrate and lower calcium oxalate saturation, which could help protect against stones. As for supplementation, calcium and vitamin D do not appear to significantly raise urinary calcium or stone risk, with calcium potentially reducing intestinal oxalate absorption and vitamin D alone not causing hypercalciuria. Medications like thiazides and bisphosphonates may further help by lowering urinary calcium and reducing stone forming potential in women with hypercalciuria.Conclusions Overall, neither hormone replacement therapy or calcium or vitamin D supplementation consistently increases kidney stone risk in postmenopausal women. Individual metabolic assessment remains essential, particularly for women with a history of nephrolithiasis or known risk factors for calcium stone formation.