Adverse prognosis of nasopharyngeal carcinoma following long-term exposure to multiple air pollutants

Air pollution is potentially leading to cancer mortality; however, there is little evidence for a link between nasopharyngeal carcinoma and air pollution. In particular, limited studies have examined the role of traffic and multiple chemical components on the prognosis of this carcinoma. Here, we hypothesized that fine particulate matter (PM2.5) and traffic-related compositions, i.e., black carbon and organic matter, and ozone (O-3), might be associated with increased mortality. We collected individual-level data from a 10-year nasopharyngeal cohort in southern China. Time-varying Cox models were developed. Traffic proximity and road density were studied. Results show that The hazard ratios for each interquartile range elevation in O-3, black carbon and organic matter were 1.14, 1.21, and 1.22, respectively, whereas hazards for PM2.5 were significant only at above 31.2 mu g/m(3). Women and patients below 49 years were susceptible to PM2.5, while men and patients above 50 years were vulnerable to high levels of black carbon, organic matter, and O-3. The mortality risks were 28-33% or 16-73% greater for those living near traffic or in high-road density areas. There were positive associations between multiple air pollutants and nasopharyngeal carcinoma mortality among various subgroups.