Study On Mortality And Its Trends For Lung Cancer And Mesothelioma In The Crocidolite Contaminated Area In Dayao County

Introduction: The objective of the investigation was to explore the mortality rate of lung cancer and malignant mesothelioma in people who was exposed to environmental crocidolite, to approach the relation between lung cancer or mesothelioma and environmental crocidolite exposure. In addition, to predict the future trends for lung cancer and mesothelioma by the exponential smoothing model so as to provide epidemiological evidences for prevention and control of the diseases.Methods A 17-year (1987-2003) fixed cohort study was used to evaluate the mortality of lung cancer and malignant mesothelioma among residents over 30 years old in the Dayao County contaminated with crocidolite, comparing the mortality of lung cancer and mesothelioma between the Dayao county and the national mortality, analyzing the mortality trends for lung cancer and mesothelioma in the five main town and predicting the future mortality of lung cancer and mesothelioma by utilizing the Holt exponential smoothing model simultaneously.Results: The fixed cohort study was made on 6249 residents (male 3530, female 2719), the total person-years was 95855. 75. There were 84 persons died from the lung caner and mesothelioma in the cohort, the total mortality is 87. 6 per 100000 person-years. Lung cancer andthe mesothelioma were the first and third cause of tumor death respectively, and the mortality is 63.6/100000 person-years and 24.0/100000 person-years respectively, indicating the high mortality of lung cancer and mesothelioma correlated with environmental contaminated crocidolite.The number of lung malignant tumor was 268(122 persons mesothelioma included) from 1994 to 2003 year in the five main towns. The mortality of lung malignant started to decrease from 2001 years, if it is true, the further study should be carried out to conform the situation. The mortality of mesothelioma rose up slowly during the observational periods and the trend will last for a while. The results by the Holt exponential smoothing indicated that the number of lung malignant tumor will increase by 205 persons (105 persons mesothelioma included) in the future five years, and the mortalities of lung malignant tumor and mesothelioma will reached 30. 62/10" and 19.53/10' by 2008 respectively.Conclusion: Environmental exposure to crocidolite led to high mortalities of lung malignant tumor and mesothelioma among residents in Dayao County. The number and mortality of lung malignant tumor (mesothelioma included) will maintain to rise during 2004-2008 years. So the preventive measures should be taken for controlling the crocidolite concentration in order to protect people' s health.