ABSTRACT
In coal mines, main occupational hazard is coal-mine dust, which can cause health prob-lem including coal workers' pneumoconiosis and lung cancer. Some heat shock proteins (Hsps) have been reported as an acute response to a wide variety of stressful stimuli. Whether Hsps protect against chronic environmental coal-mine dust over years is unknown. It is also interesting to know that whether the expression of Hsp27 and Hsp70 proteins as a marker for exposure is associated risk of lung cancer among coal miners. We investigated the association between levels of Hsp27 and Hsp70 expression in lymphocytes and plasma and levels of coal-mine dust exposure in workplace or risk of lung cancer in 42 cancer-free non-coal miners, 99 cancer-free coal miners and 51 coal miners with lung cancer in Taiyuan city in China. The results showed that plasma Hsp27 levels were increased in coal miners compared to non-coal miners (P<0.01). Except high cumulative coal-mine dust exposure (OR= 13.62, 95%CI=6.05-30.69) and amount of smoking higher than 24 pack-year (OR=2.72, 95%CI=1.37-5.42), the elevated levels of plasma Hsp70 (OR= 13.00, 95% CI=5.14-32.91) and plasma Hsp27 (OR=2.97, 95% CI=1.40-6.32) and decreased expression of Hsp70 in lymphocytes (OR=2.36, 95% CI=1.05-5.31) were associated with increased risk of lung cancer. These findings suggest that plasma Hsp27 may be a potential marker for coal-mine dust exposure. And the expres-sion of Hsp27 and Hsp70 levels in plasma and lymphocytes may be used as biomarkers for lung can-cer induced by occupational coal-mine dust exposure.
ABSTRACT
To investigate the health impacts of crystalline silica mixed dust and other potential occupational hazards on workers in ceramic factories, a cohort study of 4851 workers registered in the employment records in 3 ceramic factories in Jingdezhen city of China between 1972 and 1974 was identified2 The cohort mortality was traced throughout 2003 with an accumulation of 128970.2 person-years, revealed 1542 deaths. Standardized mortality ratios (SMRs) were calculated for the main causes of death by using Chinese national mortality rates as reference. The mortality from all causesin three ceramic factories was 12.0‰ and the cumulative mortality was 31.8%. Malignant neoplasm,cardiovascular diseases, respiratory diseases, infectious diseases were the first four illnesses that threaten workers' life, and they accounted for 73.2% of all deaths. The resultsof this study showed that the standardized mortality ratio for all subjects was 1.02, which is very close to that expected on the basis of the China national mortality rates. Statistically significant mortality excesses for respiratory disease (SMR=1.36), pneumoconiosis (SMR=37.34), infectious disease (SMR=5.70) and pulmonary tuberculosis (SMR=3.88) were observed. The mortality of 2938 dust-exposed workers was higher than that of 1913 non dust-exposed workers. Except for pneumoconiosis, the mortality from lung cancer, non-malignant respiratory diseases and pulmonary tuberculosis in dust-exposed workerswere significantly increased as compared with that in non-exposed workers, and the relative risks(RRs) were 1.86 (1.16-2.99), 2.50 (1.84-3.40), 1.81 (1.34-2.45). The exposure-response relationships between cumulative dust exposure level and mortality from all causes, colorectal cancer, lung cancer, respiratory diseases, and pulmonary tuberculosis were also identified. The findings indicatedthat silica mixed dust in ceramic factories has harmful impact on the workers' health and life span in ceramic factory.