Microplastics, plastics, and their products exposures and cancer: a pooled analysis

OBJECTIVE: This meta-analysis aims to evaluate the impact of microplastic pollutant exposure on cancer risk by analyzing data from existing cohort and case-control studies. METHODS: The researchers systematically searched PubMed, Embase, and the Cochrane Library on 30 June 2024 to identify relevant studies. The analysis focused on cancer incidence and mortality, with subgroup analyses performed for different types of cancers and microplastic pollutants, and dose-response analysis for further investigation. Publication bias was assessed by funnel plots, Egger's test, and Begg's test. All data processing and analyses were performed using Stata (V.18.0) and R (V.4.5.0) software. This study was conducted without using artificial intelligence (AI) tools in accordance with the TITAN Guidelines 2025. RESULTS: 43 studies involving 1 006 510 patients were included in this meta-analysis, including 32 case-control studies and 11 cohort studies. The findings indicated that exposure to microplastic pollutants was a risk factor for overall cancer incidence in case-control studies (OR = 1.10, 95% CI = 1.01 to 1.19), but not for cohort studies (OR = 1.04, 95% CI = 0.96 to 1.12). Subgroup and dose-response analyses revealed that phthalates (OR = 1.28, 95% CI = 1.08 to 1.51) and bisphenol A (OR = 1.038, 95% CI = 1.012 to 1.065) might be associated with cancer risk in case-control studies. CONCLUSION: Existing evidence from case-control studies suggests a weak correlation between microplastic pollutant exposure and cancer risk. However, this causal relationship needs to be interpreted with caution due to the methodological limitations of existing evidence.