Background

Cadmium exposure has been associated with increased diabetes risk in several studies, though there is still considerable debate about the magnitude and shape of the association.

Objective

To perform a systematic review and meta-analysis of observational studies investigating the relation between cadmium exposure and risk of type 2 diabetes and prediabetes, and to summarize data on the magnitude and shape of the association.

Data source

After conducting an online literature search through October 1, 2021, we identified 42 eligible studies investigating the association between cadmium exposure and risk of diabetes and prediabetes.

Study eligibility criteria

We included studies that assessed cadmium exposure through biomarker levels; examined type 2 diabetes or prediabetes among outcomes; and reported effect estimates for cadmium exposure for meta-analysis only.

Study appraisal and synthesis methods

Studies were evaluated using ROBINS-E risk of bias tool. We quantitively assessed the relation between exposure and study outcomes using one-stage dose-response meta-analysis with a random effects meta-analytical model.

Results

In the meta-analysis, comparing highest-versus-lowest cadmium exposure levels, summary relative risks (RRs) for type 2 diabetes were 1.24 (95% confidence interval 0.96–1.59), 1.21 (1.00–1.45), and 1.47 (1.01–2.13) for blood, urinary, and toenail matrices, respectively. Similarly, there was an increased risk of prediabetes for cadmium concentrations in both urine (RR = 1.41, 95% CI: 1.15–1.73) and blood (RR = 1.38, 95% CI: 1.16–1.63).

In the dose-response meta-analysis, we observed a consistent linear positive association between cadmium exposure and diabetes risk, with RRs of 1.25 (0.90–1.72) at 2.0 µg/g of creatinine. Conversely for blood cadmium, diabetes risk appeared to increase only above 1 µg/L. Prediabetes risk increased up to approximately 2 µg/g creatinine above which it reached a plateau with RR of 1.42 (1.12–1.76) at 2 µg/g creatinine.

Limitations and conclusions

This analysis provides moderate-certainty evidence for a positive association between cadmium exposure (measured in multiple matrices) and risk of both diabetes and prediabetes.

中文翻译：

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镉暴露与糖尿病和糖尿病前期风险：系统评价和剂量反应荟萃分析

背景

在几项研究中，镉暴露与糖尿病风险增加有关，尽管关于这种关联的程度和形式仍有相当大的争议。

客观的

对调查镉暴露与 2 型糖尿病和前驱糖尿病风险之间关系的观察性研究进行系统回顾和荟萃分析，并总结有关关联程度和形状的数据。

数据源

在截至 2021 年 10 月 1 日进行在线文献搜索后，我们确定了 42 项符合条件的研究，调查镉暴露与糖尿病和前驱糖尿病风险之间的关系。

研究资格标准

我们纳入了通过生物标志物水平评估镉暴露的研究；检查结果中的 2 型糖尿病或前驱糖尿病；并报告镉暴露的影响估计仅用于荟萃分析。

研究评价与综合方法

研究使用 ROBINS-E 偏倚风险工具进行评估。我们使用带有随机效应荟萃分析模型的一阶段剂量反应荟萃分析定量评估暴露与研究结果之间的关系。

结果

在荟萃分析中，比较最高与最低镉暴露水平，2 型糖尿病的总相对风险 (RR) 为 1.24（95% 置信区间 0.96-1.59）、1.21（1.00-1.45）和 1.47（1.01- 2.13) 分别用于血液、尿液和脚趾甲基质。同样，尿液（RR = 1.41, 95% CI: 1.15–1.73）和血液（RR = 1.38, 95% CI: 1.16–1.63）中镉浓度的糖尿病前期风险增加。

在剂量反应荟萃分析中，我们观察到镉暴露与糖尿病风险之间存在一致的线性正相关关系，2.0 µg/g 肌酐时的 RR 为 1.25 (0.90–1.72)。相反，对于血镉，糖尿病风险似乎仅增加超过 1 µg/L。前驱糖尿病风险增加至约 2 µg/g 肌酐，高于此水平时，在 2 µg/g 肌酐时，RR 达到 1.42 (1.12–1.76) 的平台期。

限制和结论

该分析为镉暴露（在多个矩阵中测量）与糖尿病和糖尿病前期风险之间存在正相关关系提供了中等质量的证据。