| Summary: | 碩士 === 國立臺灣大學 === 預防醫學研究所 === 93 === Introduction: Whether miners with pneumoconiosis were at increased risk for all-cause or specific-cause death is still controversial. Individual correlates in association with the risk for death among coal workers’pneumoconiosis (CWP) have not been fully addressed. To throw light on these points is of paramount importance to retired miners at Rueifang Township where the cause of pneumoconiosis has been the top five leading causes in 2001.
Objectives: The aim of this study is to use SMR analysis with Bayesian approach to assess whether CWP cases lead to an increase in total mortality and specific cause mortality by combing information obtained from previous study with current data. A case-control study was also conducted to assess the effect of exposure to underground mining on the risk for death and to identify significant individual correlates and their effect modification with exposure to coal mine workers.
Methods: We first identified a retrospective cohort with 548 retired male miners diagnosed as pneumoconiosis who sought medical consultation or seasonal flu vaccination at Rueifang Health Center. The time period for the collection of the data was from 1st of July, 2000 till 30th of June, 2004. We ascertained 79 deceased patients after linkage with mortality registry. Frequentist or Bayesian Method for Standard Mortality Ratio Analysis was used to calculate the SMR ratio to see if there was any increase in total mortality or a variety of causes of death. The ratio of 1:2 case-control study was designed with 79 deaths as the case and twice number of subjects randomly selected from the CWP cases still alive as the control group,. Information on tuberculosis (TB) was linked to the pulmonary TB prevention web site of the Center for Disease Control, Taiwan for the prevalence of TB. Other information was administered by a telephone-interview questionnaire with proxy subjects for the deceased. A logistic regression model was used to identify individual correlates associated with the risk for death.
Results: Using the Bayesian Method, all-cause death in patients with pneumoconiosis was significantly increased in comparison with general population (SMR:120, 95% CI: 116-124). The main causes for the increase was attributed to respiratory diseases (SMR: 402, 95% CI: 320-506). In all cancers’ mortality rate, there was no statistically significant increase (SMR: 101, 95% CI: 95-107), but stomach cancer rate had a remarkable increase in risk for death (SMR: 132, 95% CI: 100-175). In case-control study, the results show that TB, smoking habits, age and the number of year working in the mining pit were three independent significant factors and have respective adjusted odds ratios with the orders of 2.61 (95% CI: 1.28-5.30), 2.00(95% CI: 1.04-3.85), 1.09(95% CI: 1.02-1.17) and 1.08(95% CI: 1.03-1.14).
Conclusion： The present study demonstrated that CWP cases have significantly higher risk for all-cause death, stomach cancer, and non-malignant respiratory disease. TB, smoking habit and number of years working in the mining pit were three principal factors responsible for death.
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