| Abstract: | Background: Da-yao, located in Southwestern China, is covered with top soilrich in crocidolite ore (“blue clay”). Situated in a remote, difficult to access area,most of the rural population of 280,000, are poor peasants. The blue clay has been commercially used to make cooking stoves for decades, and the making process created high asbestos exposures. Officially, stove-making has been banned in the 1990s. Blue clay was also used as building blocks and plastering walls for houses, and in filling potholes for unpaved roads. With the advent of speeding motor vehicles, children going to school and peasants working out-doors became vulnerable when clouds of dust were created.Methods: Follow up of a cohort of 6,249 residents established in 1987 for 17-year vital status analysis of causes of deaths, and verification of mesothelioma cases. Comparison was made with a non-exposed community. Review of local statistics and studies published in Chinese were also included.Results: Prevalence of pleural plaques was 19.8%, for age 40 and over. There were 61 lung cancer deaths (mortality rate 63.64/10 5 ) and 24 mesothelioma deaths (25.04/10 5 ) in the cohort, and in the comparison group, 35 lung cancer deaths (45.35/105), with RR=1.43. Smoking rates were identical in both groups(67%). Crocidolite attributable lung cancer was 30.3%.Conclusions: Besides mesothelioma, crocidolite exposure contributed to a43% increase in lung cancer, which was 2.5 times larger in number than meso-thelioma. In this community, nearly one third of lung cancer can be attributed tocrocidolite exposures, a public health condition as serious as mesothelioma. |
