B99
Occupational exposure to Crystaliline Silica and carcinogenic risk in the Czech black-coal miners without pneumoconiosis longitudinal study (1992 2006)
Hana Tomaskova1, Zdenek Jirak1, Anna Splichalova2, Pavel Urban3, Vladislava Zavadilova1
1University of Ostrava, Faculty of Health Studies, Ostrava, Czech Republic, 2Institute of Public Health Ostrava, Ostrava, Czech Republic, 3National Institute of Public Health, Praha, Czech Republic
Background
In black coal mines, the main risk factor is dust containing crystalline silica that was classified by IARC as a human carcinogen in 1997. In this longitudinal epidemiological study, carcinogenic risk was analysed in the cohort of 6,705 black-coal miners without pneumoconiosis.
Method
The sample included miners without pneumoconiosis who were working in the mining profession for at least 8 years. The individual and occupational data were combined with the data from the National Cancer Register and the National Population Register. The relative risk of cancer (lung, stomach, colon, kidney, urinary bladder) was calculated as SIR (Standardized Incidence Ratio) over the period 1992 2006 between miners and general Czech population.
Cox proportional hazards model was used for analysis of relationship between lung cancer and smoking habits, duration of professional exposure controlled for age.
Results
In the cohort, 464 newly registered cases of cancer and 681 deaths were found in the period 1992 2006. The main causes of death were cardiovascular diseases (32 %) and cancer (30 %). SIR was not statistically significant higher for any specific cancer (lung N=93, SIR=0.87, stomach N=20, SIR=1.15, colon N=35, SIR=0.87, kidney N=24, SIR=0.66, urinary bladder N=19, SIR=0.72).
Average duration of exposure was 22.9 years (SD=5.9) and 80 % of miners were smokers or ex-smokers. Only relative risk of lung cancer for smokers, controlled for age, was significant higher (HR=3.22, 95% IC 1.66 6.25).
Conclusion
The risk of specific cancers in miners without pneumoconiosis was comparable to the risk in general population. The main risk factor for lung cancer was smoking.
Acknowledgements
The study was supported by grant of the Czech Ministry of Health No. 6578 and No. 8556
