Microplastic Pollution and Risk of Cancer: A Prospective Study Based on UK Biobank.

IntroductionVarious industrial pollutants have been implicated in tumorigenesis. However, the cancer risk associated with microplastics, a pervasive environmental pollutant, remains poorly understood. This study aimed to evaluate the association between basin-level environmental microplastic contamination and cancer incidence.MethodsIn this secondary analysis of a prospective UK Biobank cohort, 378,985 participants were linked to basin-level river microplastic measurements using residential coordinates. The 2019 measurements were treated as an ecological proxy for regional environmental microplastic contamination. Participants were categorized into low, moderate, or high exposure groups, and Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).ResultsDuring a mean follow-up of 12.39 years, 37,322 participants developed at least one of the 24 cancer outcomes. Compared with participants in low-exposure basins, participants in high-exposure basins had increased risks of liver cancer (HR, 1.252; 95% CI, 1.031-1.520), colon cancer (HR, 1.167; 95% CI, 1.088-1.252), and lung cancer (HR, 1.198; 95% CI, 1.095-1.309). These estimates represent modest relative increases and should be interpreted alongside absolute event counts and confidence intervals.ConclusionsHigher basin-level river microplastic contamination was associated with modestly higher incidence of selected digestive and respiratory cancers.Patient or Public ContributionThis study was a secondary analysis of de-identified data from the prospective UK Biobank cohort. Patients, service users, and members of the public were not directly involved in the design, analysis, interpretation, or preparation of this study.