Background and Objective: Breast cancer is the most common malignancy in women worldwide. Cadmium is one of the most persistent and toxic heavy metals, exposure to which may lead to an increased risk of breast cancer. This study aims to quantitatively summarize the available evidence for the relationship between cadmium exposure and the risk of breast cancer using a systematic review and meta-analysis.
Materials and Methods: In this research, observational studies that investigated the relationship between cadmium and breast cancer until May 2022 and were published in international databases were searched and retrieved. To determine the heterogeneity, the statistical tests Chi2 and I2 were used, to determine the presence of publication bias Egger's and Begg's tests were used, and to detect the root of the heterogeneity, meta-regression, and sensitivity analysis were used.
Results: In this study, it was observed that compared to the base group, the relative risk of breast cancer in people exposed/exposed to a dose higher than the base level of cadmium is equal to 1.10 (95% CI: 1.06-1.14; p ≤ 0.001), therefore, a statistically significant relationship was observed between exposure to cadmium or exposure to levels exceeding the baseline and developing breast cancer. In investigating the possibility of publication bias, the result of Egger's test was equal to (p ≥ 0.001), and the result of Bagg's test was equal to (p = 0.099).
Conclusion: According to the available evidence, exposure to cadmium leads to an increase in the risk of breast cancer, and this increase in risk is statistically significant.
