A Retrospective Cohort Study On Risk Factor Of Major Cancer In Crocidolite-Contaminated Area In Dayao County

ObjectiveThis study was aimed to collect the information of environmental low-dose exposure to crocidolite on cancer related death so as to provide the epidemiological evidence for cancer prevention and after studies in this local area.MethodA 26-year retrospective cohort study was used to evaluate the mortality of major cancer in Crocidolite-Contaminated Area in Dayao County. We chosen Jinbi and Xinjie which is serious asbestos exposure as samples and selected 16 villages randomly for the survey sites. Provide 26 years retrospective follow-up for farmer who over the age of 20 when 1984 in survey sites.ResultsThe fixed cohort study was made on 804 residents (male 356, female 448), the total man-year was 17724.00. There were 42 person died from cancer in the cohort, the total mortality is 236.97 per 100000 person-years. Hepatic carcinoma was the first cause of tumor death and the mortality is 56.42 per 100000 person-years. Lung cancer was the second cause of tumor death and the mortality is 50.78 per 100000 person-years. Gastric cancer and intestinal cancer mortality were 33.85 per 100000 person-years. The mortality of cervical cancer and malignant pleural mesothelioma were 11.28 per 100000 person-years. There were 38 objects died of cancer in person who self-reported the history of occupational exposure to crocidolite, only 4 objects died of cancer in person who self-reported without history of occupational exposure to crocidolite. Asx2=43.389, P=0.000<0.001, that the difference was statistically significant. Logistic analysis showed that the risk of died from cancer who exposed to crocidolite is 10.215 times higher than those who did not.ConclusionThe lowest cancer mortality in the country of Yunnan Province, but the cancer mortality in crocidolite-Contaminated Area in Dayao County not only higher than in Yunnan, it is far more than the national average. Also liver, lung, stomach, colon, cervical cancer, pleural mesothelioma and other malignant tumors were higher than those in Yunnan and the national average. We speculated that long-term environmental crocidolite exposure led to high mortality of cancer among residents in crocidolite-Contaminated Area in Dayao County.