The preceding projects, "Epidemiological evidence quartz, silicosis and lung cancer" (sub-projects I-III), quantified the dose-response relationship, i.e. the relationship between the lifetime risk of silicosis and lung cancer and the exposure to respirable quartz dust. The results of the studies indicate that the effects of quartz are dependent not only upon the exposure dose, but also upon the variability and begin of exposure. The present follow-on project was to quantify silicosis and lung cancer and further possible health effects of exposure to respirable quartz dust, such as the overall mortality and cardiovascular diseases.
The results were made available to sub-committee III of the Committee on Hazardous Substances (AGS).
The morbidity/mortality data in the Chinese quartz cohorts (n = approx. 70,000) were surveyed for the period from 1960 to 2003. Individual exposure to respirable quartz dust, smoking, and other forms of exposure were recorded by means of standardized and validated surveys. The dose-response relationship between respirable quartz dust exposure and overall mortality and other diseases was quantified.
Following adjustment for age, sex and smoking, a significant dose-response relationship between exposure to respirable quartz dust and overall mortality was detected in the cohort. First results showed that 15.2% of all mortalities in the Chinese quartz cohort occurred in the group with long term exposure to respirable quartz dust. The cause of the elevated mortality is however not only chronic respiratory diseases, but also cardiovascular diseases.
Further analyses of the data are in progress.
epidemiologyDescription, key words:
silica, epidemiology, China, cohort study, a dust, mortality