Association between ambient air pollution and laryngeal neoplasms incidence in twelve major Chinese cities, 2006–2013

Epidemiological evidence has suggested that ambient air pollution is an increasingly important risk factor for respiratory diseases without assessing its influence on laryngeal neoplasms incidence in China. We constructed two-way fixed effect models and Poisson regression models to explore the effects of ambient air pollutants including nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and particulate matter less than or equal to 10 μm in aerodynamic diameter (PM₁₀) on incidence of laryngeal neoplasms in twelve major cities in China over the period 2006–2013. The annual average concentration for PM₁₀, SO₂, and NO₂ was 107.22 μg/m³, 44.07 μg/m³, and 46.71 μg/m³ with standard deviations of 24.84 μg/m³, 13.68 μg/m³, and 9.19 μg/m³, respectively. We observed that ambient air pollutants were significantly positively correlated with the incidence of laryngeal neoplasms, especially for NO₂. The relative risks of overall incidence of laryngeal neoplasms in the current period were 1.20, 1.04, and 1.00 for NO₂, SO₂, and PM₁₀, with 95% confidence intervals (CIs) of 1.01–1.43, 0.93–1.16, and 0.96–1.05, respectively. Moreover, this deleterious impact was stronger in the male than in the female, likely due to genetic predisposition caused by longer exposure to more serious air pollution for men. Our findings complement the epidemiological evidence of laryngeal neoplasms due to ambient air pollution and reinforce the necessity of policy efforts to control the noxious air pollution emissions.