Information from the abstract
Background: Ambient fine particulate matter (PM₂.₅) is a recognized environmental carcinogen; however, its association with head and neck cancer (HNC) remains incompletely characterized. This study systematically evaluated the relationship between long-term PM₂.₅ exposure and HNC risk, with emphasis on internal validity. Methods: A systematic review and meta-analysis of observational studies were conducted following PRISMA 2020 guidelines and a prespecified PROSPERO protocol (CRD420261362646). Comprehensive searches of electronic databases and grey literature were performed without restriction. Eligible studies reported quantitative associations between ambient PM₂.₅ exposure and incident HNC. Adjusted effect estimates were pooled using random-effects models. Risk of bias was assessed using the Newcastle–Ottawa Scale and ROBINS-I, focusing on confounding control, exposure assessment validity, and outcome ascertainment. Results: Sixteen studies were included in the systematic review, of which sixteen contributed to the primary quantitative synthesis. Long-term PM₂.₅ exposure was associated with a modest but statistically significant increase in HNC risk (pooled RR = 1.25, 95% CI: 1.16–1.35), with evidence of exposure–response relationships. Between-study heterogeneity was moderate (I² ≈ 40–65%). Cohort studies with robust adjustment for smoking and alcohol use yielded more stable estimates, whereas ecological and less-adjusted studies showed greater variability. Overall risk of bias was moderate, primarily due to residual confounding and exposure misclassification. Conclusions: PM₂.₅ exposure is associated with increased HNC risk, supporting its role as an environmental carcinogen. However, internal validity limitations warrant cautious interpretation. Future studies should prioritize individual-level exposure assessment and rigorous confounder control.
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This record has an Impact Signal of 73/100 based on recency, source, collaboration, and bibliographic signals. It prioritizes monitoring and is not a judgment of research quality.
Related topics: Air Quality and Health Impacts · Head and Neck Cancer Studies · Carcinogens and Genotoxicity Assessment
Thai researcher and institutional participation
Patcharakan Tangtrairattanakul · Prayuth Poowaruttanawiwit · Chanida Chantim · Naresuan University
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