Occupational exposure to diesel exhaust and head and neck cancer: a systematic review and meta-analysis of cohort studies

• Published in: European journal of cancer prevention Vol. 33; no. 5; pp. 425 - 432
• Main Authors: Seyyedsalehi, Monireh Sadat, Collatuzzo, Giulia, Teglia, Federica, Boffetta, Paolo
• Format: Journal Article
• Language: English
• Published: England 01-09-2024
• Subjects: Cohort Studies; Head and Neck Neoplasms - chemically induced; Head and Neck Neoplasms - epidemiology; Head and Neck Neoplasms - etiology; Humans; Occupational Diseases - chemically induced; Occupational Diseases - epidemiology; Occupational Diseases - etiology; Occupational Exposure - adverse effects; Vehicle Emissions - toxicity
• ISSN: 0959-8278; 1473-5709; 1473-5709
• DOI: 10.1097/CEJ.0000000000000876

Exposure to diesel exhaust (DE) and other fossil fuels in the workplace can cause several health effects including cancer. We conducted a systematic review and meta-analysis of cohort studies examining the association between occupational DE exposure and the risk of head and neck cancer (HNC), including cancer of the oral cavity, pharynx and larynx. We included cohort studies mentioned in the Monograph of the International Agency for Research on Cancer, 2014, on DE. Forest plots of relative risk (RR) were constructed for HNC overall and its anatomical subtypes. A random-effects model was used to address heterogeneity between studies. Fifteen articles were included after removing duplicates and irrelevant reports. The summary RR for DE exposure was 1.08 [95% confidence interval (CI) = 1.01-1.17, P heterogeneity = <0.001] for HNC overall, 0.98 (95% CI = 0.87-1.11) for oral cavity, 1.05 (95% CI = 0.77-1.43) for pharyngeal, 1.15 (95% CI = 0.96-1.38) for oral cavity and pharyngeal combined, and 1.13 (95% CI = 1.03-1.24) for laryngeal cancer. There were elevated RRs for incidence studies of HNC (RR = 1.13; 95% CI = 1.05-1.22, P  = 0.001), European studies (RR = 1.13; 95% CI = 1.05-1.23, P  = 0.001), and female studies (RR = 1.77; 95% CI = 1.31-2.39, P  = 0.003). Our study suggested an association between occupational DE exposure and the risk of HNC, particularly laryngeal cancer. Although residual confounding cannot be ruled out, our results support the importance of controlling occupational DE exposure.