The Relationship Between Hormone Replacement Therapy and Risk of Kidney Cancer in Women: A Meta-Analysis

Results from the epidemiologic studies on the relationship between hormone replacement therapy (HRT) and the risk of kidney cancer in women were not completely consistent. This meta-analysis aimed to evaluate the relationship between HRT and risk of kidney cancer in women. We performed a meta-analysis of observational studies to assess this association. The PubMed and Embase databases were searched from their inception to January 29, 2020, to identify relevant studies that fit the pre-stated inclusion criteria; reference lists from the retrieved articles were also been reviewed. Relative risks (RRs) with corresponding 95% CIs were extracted and combined using random effects models. Furthermore, dose–response, sensitivity analyses, publication bias, and subgroup analysis by study design, regional location, and exposure assessment method were conducted. Thirteen articles involving 6 cohort studies and 8 case–control studies were included in our meta-analysis. Overall, 4194 women were diagnosed with kidney cancer among 648 107 participants. The pooled RR for kidney cancer was 1.08 (95% CI: 0.96-1.22) in those who were administered HRT compared to those who had not. Subgroup analysis indicated the overall result was not influenced by study type, regional location, or adjusted variables. Dose–response analysis showed a nonlinear relationship between HRT and kidney cancer (P = .0021) and the risk of kidney cancer decreased by 15% to 28% with 12 to 18 years of HRT use. No evidence of publication bias was found (P for Egger =.111). Our meta-analysis showed that HRT use is inversely associated with kidney cancer risk in a dose–dependent fashion.