Risk of gastric cancer in pneumoconiotic coal miners and the effect of respiratory impairment.

OBJECTIVES

This study was carried out to investigate the mortality patterns in a group of 3790 coal miners. The study population had abnormal chest x ray films at a routine medical examination that was performed in the 1950s.

METHODS

The total group of 3790 coal miners were followed up for mortality up to 1 January 1992. Causes of death, determined and coded at time of death, were traced with help from the Central Bureau of Statistics.

RESULTS

Total mortality in this group of coal miners with abnormal chest x ray films was significantly higher than expected (SMR 127.1, 95% CI 122.5-131.6), mainly a reflection of the increase in mortality from non-malignant respiratory disease (SMR 411.0, 95% CI 382.3-441.3). Mortality from gastric cancer was also significantly increased (SMR 147.5, 95% CI 122.3-176.3). This risk of mortality from gastric cancer was confined to workers with no pneumoconiosis or only a mild form. Despite the strong relation to duration of employment and pneumoconiosis the group of workers with more severe manifestations of pneumoconiosis did not experience an excess in mortality from gastric cancer.

CONCLUSION

This study confirms the earlier reported risk of gastric cancer in coal miners. Also it confirms the hypothesis that this risk of gastric cancer is limited to workers with a mild degree of pneumoconiosis or none. In workers with severe forms of pneumoconiosis the pulmonary clearance system is impaired in such a way that the inhaled coal dust does not reach the digestive tract.