Impacts of long-term PM2.5 exposure on Endocrine related cancer patients in South Korea

BACKGROUND AND AIM In previous studies, endocrine tumors reported to be associated with endocrine disrupting chemicals (hereafter, EDCs). Among EDCs, air pollution is a carcinogen classified as an environmental factor. We investigated the relationship between air pollution and endocrine tumors. METHODS National health insurance recipients are subject to regular national health checkups. We linked this information with the data of the occurrence of the first cancer from the national cancer registration project. Those who were diagnosed with cancer (breast cancer (C50), prostate cancer (C61), and thyroid cancer (C73)) were selected from the health checkup subjects between 2007 and 2010. The Extreme Boosting model was trained on a dataset gained from both satellite and observational data collected from 2015 to 2020 in South Korea. The model was used to predict monthly average PM2.5 values for each 1km grid nationwide for the period from 2007 to 2020. Grid values within a city district were averaged to obtain a monthly average PM2.5 value for all nationwide 229 city districts. We employed Cox’s proportional hazards models with age, sex (only thyroid cancer patients), Body Mass Index (BMI), smoking status, blood pressure, waist circumference and total cholesterol as covariates. Follow-up started at 2007 following entry into the cohort, and the end date of the study was 31th Oct. 2021. Annual mean ambient PM2.5 of the patients’ residential address was used as time-varying exposures. RESULTS In the time-varying cox model, the hazard ratio (HR) of mortality was 1.042 (95%CI: 1.031-1.052), 1.031 (95%CI: 1.022-1.039) and 1.029 (95%CI: 1.016-1.042) for breast cancer, prostate cancer patients and thyroid cancer patients, respectively. CONCLUSIONS We observed that an increase in PM2.5 concentrations increased the risk of mortality in patients diagnosed with breast cancer, prostate cancer, and thyroid cancer, respectively. KEYWORDS Endocrine-related cancer, cohort study, fine particle matter, Extreme Boosting model