Background Existing studies suggest that cadmium exposure is associated with the occurrence of cardiovascular disease (CVD), but the current epidemiological evidence is inconsistent.

Objective To systematically evaluate the relationship between cadmium exposure and CVD through meta-analysis.

Methods We systematically searched PubMed, Cochrane Library, Web of Science, CNKI, Wanfang and SinoMed databases to collect observational studies on the relationship between cadmium exposure and CVD in human population published until July 30, 2024. On the basis of following predetermined inclusion and exclusion criteria, the retrieved literature was systematically screened, and the basic information of the included research was extracted, including basic participant information, research outcomes, and data results. This study used the Newcastle-Ottawa Scale and a cross-sectional study evaluation protocol (11 items) recommended by the Quality of Health Care and Research Institutions of the United States for literature quality evaluation. Meta-analysis, subgroup analysis, sensitivity analysis, and assessment of publication bias of the data were conducted using Stata16.0 software.

Result A total of 15 studies (18 datasets) were included, and the quality of all the studies was graded as medium or above. Among them, there were 10593 cases of CVD and 86801 controls. The results of meta-analysis showed that the standard mean difference (SMD) of the CVD case group was 0.44 and 95% confidence interval (95%CI) was (0.30, 0.58), and the cadmium exposure level of the CVD case group was higher than that of the control group (P<0.05). The subgroup analysis showed that the cadmium exposure levels in the CVD patients from the Americas (SMD=0.46, 95%CI: 0.29, 0.63) and Europe (SMD=0.14, 95%CI: 0.09, 0.19) were higher than those in the control group (P<0.05). The cadmium levels in blood (SMD=0.52, 95%CI: 0.31, 0.73) and urine (SMD=0.34, 95%CI: 0.16, 0.52) in the CVD case group were higher than those in the control group (P<0.05). In those cross-sectional studies (SMD=0.34, 95%CI: 0.23, 0.46), the cadmium exposure level in the CVD patients was higher than that in the control group (P<0.05). The sensitivity analysis showed robust meta-analysis results and the assessment of publication bias also showed no publication bias.

Conclusion Cadmium exposure may increase the risk of cardiovascular disease after multiple studies were combined by meta analysis, suggesting that the scope and level of cadmium exposure in the population should be further controlled.