{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,28]],"date-time":"2026-06-28T03:51:41Z","timestamp":1782618701904,"version":"3.54.5"},"reference-count":30,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T00:00:00Z","timestamp":1773187200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002842","name":"Chiang Mai University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100002842","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Public Health"],"abstract":"\n Background<\/jats:title>\n \n Northern Thailand experiences severe annual air pollution (PM\n 2.5<\/jats:sub>\n \u202f&gt;\u202f35\u202f\u03bcg\/m\n 3<\/jats:sup>\n ), primarily due to agricultural burning. While ambient PM\n 2.5<\/jats:sub>\n has been linked to gastrointestinal cancer deaths, its effect on colon cancer survival in high-exposure areas remains understudied.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n In this 15-year retrospective cohort study, we used data on 5,018 patients with colon cancer (2003\u20132018) obtained from the Chiang Mai Cancer Registry. Time-varying exposure to PM\n 2.5<\/jats:sub>\n , PM\n 10<\/jats:sub>\n , NO\u2082, SO\u2082, CO, and O\u2083 was evaluated by exploiting annually updated Copernicus Atmosphere Monitoring Service data and linking them to residential districts. Multivariable time-dependent Cox models adjusted for demographics, tumor characteristics, and treatment were used in the analysis.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Over 18,650 person-years of follow-up (PYFU), 72% of patients died (mortality rate: 19.4 per 100 PYFU). Exposure to PM\n 2.5<\/jats:sub>\n \u202f\u2265\u202f37.5\u202f\u03bcg\/m\n 3<\/jats:sup>\n (a regionally relevant threshold) was independently linked to double the risk of all-cause mortality (adjusted hazard ratio (aHR)\u202f=\u202f1.96, 95% confidence interval: 1.49\u20132.58,\n p<\/jats:italic>\n \u202f&lt;\u202f0.001), as was having a low body mass index (aHR\u202f=\u202f1.54) and being male (aHR\u202f=\u202f1.23). Patients who died had significantly higher mean time-updated PM\n 2.5<\/jats:sub>\n exposure (with consistent annual exposure differences) compared to the survivors (37.7 vs. 35.5\u202f\u03bcg\/m\n 3<\/jats:sup>\n ;\n p<\/jats:italic>\n \u202f&lt;\u202f0.001). No significant associations were found between colon cancer and PM\n 10<\/jats:sub>\n , O\u2083, NO\u2082, SO\u2082, or CO exposure. The PM\n 2.5<\/jats:sub>\n effect size was larger than estimates from regions with lower exposure levels.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n Long-term exposure to ambient PM\n 2.5<\/jats:sub>\n markedly increases the risk of death among colon cancer patients in northern Thailand. As a modifiable risk factor, PM\n 2.5<\/jats:sub>\n mitigation urgently needs to be incorporated into environmental and survivorship care strategies in high-exposure areas.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fpubh.2026.1684020","type":"journal-article","created":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T06:52:50Z","timestamp":1773211970000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Time-varying exposure to ambient air pollution and mortality among colon cancer patients in northern Thailand: a 15-year retrospective cohort study"],"prefix":"10.3389","volume":"14","author":[{"given":"Taned","family":"Chitapanarux","sequence":"first","affiliation":[{"name":"Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrinee","family":"Traisathit","sequence":"additional","affiliation":[{"name":"Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]},{"name":"Data Science Research Center, Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pimwarat","family":"Srikummoon","sequence":"additional","affiliation":[{"name":"Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]},{"name":"Data Science Research Center, Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natthapat","family":"Thongsak","sequence":"additional","affiliation":[{"name":"Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nawapon","family":"Nakharutai","sequence":"additional","affiliation":[{"name":"Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]},{"name":"Data Science Research Center, Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Salinee","family":"Thumronglaohapun","sequence":"additional","affiliation":[{"name":"Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]},{"name":"Data Science Research Center, Department of Statistics, Faculty of Science, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Titaporn","family":"Supasri","sequence":"additional","affiliation":[{"name":"Atmospheric Research Unit of National Astronomical Research Institute of Thailand","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Phonpat","family":"Hemwan","sequence":"additional","affiliation":[{"name":"Department of Geography, Faculty of Social Sciences, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Imjai","family":"Chitapanarux","sequence":"additional","affiliation":[{"name":"Northern Thai Research Group of Therapeutic Radiology and Oncology (NTRG-TRO), Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University","place":["Chiang Mai, Thailand"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,11]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"210318","DOI":"10.4209\/aaqr.210318","article-title":"Seasonal patterns and trends of air pollution in the upper northern Thailand from 2004 to 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