Associations between PM2.5 exposure and upper tract urothelial carcinoma in a taiwanese case-control study
Chih-I Liu1,2,3, Szu-Chia Chen4,5,6, Jiun-Hung Geng7,8,9,10
1Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Background:
Upper tract urothelial carcinoma (UTUC) has a disproportionately high incidence in Taiwan, traditionally linked to aristolochic acid and arsenic exposure. Fine particulate matter (PM2.5), a Group 1 carcinogen, has been associated with various malignancies, but its role in UTUC remains unclear. This study investigated the association between PM2.5 exposure and UTUC risk.
Methods:
This retrospective case-control study used data from the Kaohsiung Medical University Hospital Research Database. Among 349,954 individuals, 74 UTUC cases (2012-2020) were identified and matched with 296 controls (1:4) using propensity score matching for age and sex. PM2.5 exposure was assessed using the PM2.5 concentration on the index date and the mean PM2.5 concentrations during the 1, 2, 3, and 5 years preceding the index date. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) per interquartile range (IQR) increase in PM2.5 exposure. Multivariable models were adjusted for age, sex, smoking status, diabetes mellitus, hypertension, and hyperlipidemia. Sensitivity analyses were performed by excluding participants with a history of smoking and by further adjusting for α-blocker use.
Results:
UTUC patients had significantly higher PM2.5 exposure across all evaluated exposure periods (all p < 0.01). In multivariable conditional logistic regression analyses, higher PM2.5 concentrations were associated with increased odds of UTUC, with adjusted odds ratios ranging from 1.436 to 2.719 per interquartile range increase in PM2.5 exposure. Similar findings were observed in sensitivity analyses excluding smokers and after further adjustment for α-blocker use.
Conclusion:
Higher PM2.5 concentrations across multiple evaluated exposure periods were associated with increased odds of UTUC in this Taiwanese case-control study. These findings suggest that ambient air pollution may contribute to UTUC risk and warrant further investigation in larger studies with more detailed information on established risk factors and individual exposure histories.
