[A study on risk of malignant neoplasm and environmental exposure to crocidolite].

Objective: To explore the risk of developing malignant neoplasm in a cohort with the history of environmental exposure to crocidolite asbestos.
Methods: A retrospective cohort and follow-up study covering 15 years (1987 --> 1995 --> 2001) was carrid out in a small town in Yunnan province. The cohort comprised 6254 local inhabitants. The deaths from and the RR of asbestos-related malignant neoplasms were studied.
Results: There were 186 deaths from neoplasms in the observation group, the mortality being 2160.5 per 10(6) person-years (RR=1.293, 95%CI: 1.032-1.618), 20 of those deaths were caused by mesothelioma, with a crude mortality of 232.3 per 10(6) person-years (RR=17.929; 95%CI: 2.406-133.592). The mortalities for men and women were 267.5 and 186.7 per 10(6) person-years respectively. The crude mortality from lung cancer (56 deaths) was 650.5 per 10(6) person-years,there is no significance between the two groups (RR=1.434; 95%CI: 0.968-2.486). The difference in mortality from gastrointestinal cancer between the two groups is not significant, whereas the risk of man intestinal cancer in the observation is significant (RR=3.71; 95%CI: 1.077-13.270).
Conclusion: The risk of developing mesothelioma is significantly increased in the population with environmental exposure to crocidolite. The risk of man intestinal cancer in the town awaits additional studies.