Long-term exposure to ambient air pollution and sequential carcinogenesis in the cardia gastric: a cross-sectional study.

[BACKGROUND] Cardia gastric cancer (CGC) is a distinct and increasingly prevalent malignancy, yet the role of air pollution in its sequential carcinogenesis remains unclear. The present cross-sectional study aimed to evaluate the associations between long-term exposure to ambient air pollution and the progression of precancerous cardia gastric lesions.

[METHODS] A total of 99,493 participants were enrolled from the National Opportunistic Screening Program for Upper Gastrointestinal Cancer in Zhejiang Province of China from 2022 to 2023. Long-term exposure to six air pollutants including particulate matter (PM), fine particulate matter (PM), sulfur dioxide (SO), nitrogen dioxide (NO), ozone (O), and carbon monoxide (CO) was assessed by using ChinaHighAirPollutants (CHAP) dataset. Cardia lesion progression was classified into five histopathological stages based on endoscopic biopsy. Ordinal logistic regression was used to examine pollutant-specific associations, restricted cubic splines (RCS) were applied to assess the potential exposure-response associations, and weighted quantile sum (WQS) regression was performed to evaluate the mixture effects.

[RESULTS] All six pollutants were significantly associated with cardia lesion progression. The adjusted odds ratios (95% confidence intervals, 95% CI) per standard deviation increment in 5-year mean concentration were 1.21 (1.17-1.25) for PM, 1.28 (1.23-1.32) for PM, 1.17 (1.13-1.21) for SO, 1.07 (1.03-1.10) for NO, 1.16 (1.12-1.20) for O, and 1.36 (1.30-1.41) for CO. RCS analyses indicated non-linear exposure-response patterns for NO, O, and CO. In mixture models, CO and PM were identified as the predominant contributors, with a 10% increase in combined exposure associated with a 10% (95% CI: 7-13%) higher risk of cardia lesion progression. Effect modification analysis revealed that Helicobacter pylori-positive individuals were more susceptible to pollution-related progression.

[CONCLUSIONS] Long-term exposure to air pollutants is associated with the progression of cardia gastric lesions, highlighting the importance of incorporating air quality improvement into cancer prevention strategies.