Shiyu Zheng, Xianwei Guo, Xiaoyan Ying
Background: The carcinogenic potential of cadmium has been suggested, but its association with endometrial cancer risk remains uncertain. This meta-analysis aimed to evaluate whether cadmium exposure is associated with the risk of endometrial cancer. Methods: A thorough search of seven databases was conducted to identify observational studies published up to September 2025. The Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) tool were utilized to evaluate the quality of observational studies. The I2 statistic was calculated to assess heterogeneity among studies. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using a random-effects model. Furthermore, sensitivity analysis, subgroup analysis, and an assessment of publication bias were performed. Results: Eight studies involving 196,456 participants were included. Study quality assessment indicated that all included studies were of moderate or high quality. Overall, cadmium exposure was associated with an increased risk of endometrial cancer (OR = 1.27, 95% CI: 1.07–1.50, I2 = 64.1%). Stronger associations were observed in case–control studies, European populations, and studies using blood or urinary cadmium biomarkers. The association remained significant in high-quality and adjusted analyses. Conclusions: The findings of this meta-analysis suggest a possible association between cadmium exposure and endometrial cancer risk. However, given the observational nature of the included studies, causality cannot be established. Further large-scale, well-designed prospective studies with standardized exposure assessment are needed to clarify this relationship.