Air Pollution and Head and Neck Cancer

TOPLINE:

Exposure to particulate matter measuring less than 2.5 µm (PM_2.5) is associated with an increased incidence of head and neck cancer (HNC), with the strongest association observed at a 5-year lag period. The study highlights the need for further subgroup analysis to understand the relationships between exposure and cancer pathogenesis.

METHODOLOGY:

• Researchers performed an epidemiological cohort analysis using data from the Surveillance, Epidemiology, and End Results national cancer database from 2002-2012.
• The study examined the relationship between US county mean PM_2.5 levels and HNC incidence rates using a linear mixed model, focusing on overall and site-specific incidences of HNC.
• A total of over 600 counties and 11 states were included in the analysis, with data linked to county-level air pollution, alcohol, and smoking use data.
• Age-adjusted incidence rates of HNC were calculated for each county, and lag models were utilized to account for the time between exposure and disease presentation.
• The primary outcome was all HNC incidences, with secondary outcomes including specific cancer subtypes such as oral cavity, oropharynx, larynx, hypopharynx, sinonasal, and middle ear cancers.

TAKEAWAY:

• PM_2.5 exposure is significantly associated with an increased incidence of HNC, with the strongest association observed at a 5-year lag period (β, 0.24; P
• Significant associations were also observed at no lag (β, 0.16; P = .02) and up to a 20-year lag period (β, 0.15; P
• The study found that PM_2.5 exposure is associated with increased incidence of specific HNC subtypes, including oral cavity and laryngeal cancers, even after adjusting for covariates.
• No significant association was found for sinonasal, hypopharyngeal, nasopharyngeal, and oropharyngeal cancers after adjusting for covariates.

IN PRACTICE:

“This study adds to the expanding body of literature that supports improved air quality standards to mitigate the effects of air pollution on development of cancer,” the authors of the study wrote.

SOURCE:

The study was led by John Cramer, of Wayne State University in Detroit, and Stella E. Lee, of Brigham and Women’s Hospital in Boston. It was published online in Scientific Reports.

LIMITATIONS:

The study was limited by its ecological design, which made it difficult to control for all confounding variables. “The availability of smoking and alcohol data was also limited at the county level before 1996, and other important covariate data regarding occupational exposures and racial and ethnic disparities were not available for the studied period,” the authors wrote. Additionally, the effects of viral-induced carcinogenesis, specifically human papilloma virus in the oropharynx and Epstein-Barr virus in the nasopharynx, were not considered due to limited data availability.

DISCLOSURES:

The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.