Long-term exposure to air pollution and esophageal cancer incidence: A large-scale prospective cohort study

Epidemiological evidence regarding the association between long-term air pollution exposures and esophageal cancer is limited and controversial. This study aims to investigate this association further and assess its impact on different histological subtypes of esophageal cancer.

Data from the UK Biobank cohort, which included 444,932 participants, was utilized for this study. High-resolution 1 × 1 km data from the UK's Department for Environment, Food and Rural Affairs was used to estimate annual concentrations of air pollutants based on participants' residential addresses. The Time-Dependent Cox proportional hazard model was employed to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) for the incidence of esophageal cancer associated with air pollutant exposure.

Over a follow-up duration of 4,777,149 person-years, 1008 new esophageal cancer cases were observed. No association between PM_2.5 and PM₁₀ exposure and esophageal cancer was found. However, long-term exposure to NO₂, NOx, SO₂ and benzene demonstrated a linear relationship with the risk of esophageal cancer incidence. The HRs were 1.278 (95 % CI: 1.104-1.480) per 10 microg/m³ for NO₂, 1.129 (95 % CI: 1.046-1.218) per 10 microg/m³ for NOx, 1.109 (95 % CI: 1.041-1.182) per 1 microg/m³ for SO₂ and 1.086 (95 % CI: 1.010-1.167) per 0.1 microg/m³ for benzene, respectively. No statistically significant heterogeneity was detected between the histological subtypes of squamous cell carcinoma and adenocarcinoma. Elderly individuals were more vulnerable to nitrogen oxides, while smokers or former smokers were more susceptible to the effects of sulfur dioxide.

Long-term exposure to air pollutants may significantly increase the risk of esophageal cancer. Effective and targeted control of ambient air pollutant concentrations could potentially reduce the disease burden of esophageal cancer.