A prospective cohort study on comparison of risk of death of respiratory system diseases between occupational dust exposure and smoking

Abstract

OBJECTIVE: To compare the effects of dust exposure and smoking on mortality of respiratory system diseases (RSD). METHODS: Based on the Guangzhou Occupational Health Surveillance Record System established between 1989 and 1992, 80,987 factory workers, aged 30 years old or older, occupationally exposed or not exposed to dusts, were included in a prospective cohort study. RESULTS: (1) The mean age of the cohort was 43.5. Most subjects were workers, had secondary education, and almost all were married. The dust exposure rate was 16.3%, the smoking rate 43.7% and the alcohol-drinking rate 33.5%. (2) The cohort was followed up for 8 years on average, but 35 people (0.04%) were lost for follow up. Among the 1593 deaths, 219 and 90 people died of lung cancer and non-cancer respiratory system diseases (NCRSD) respectively. (3) The adjusted relative risk (RR) of death of lung cancer for smokers, 3.32, was 2.2 times of that for dust exposed workers, 1.53, and the RR of death of NCRSD for dust exposed workers, 2.41, 1.28 times of that for smokers, 1.89, especially for silica dust-exposed workers, 5.72, 3.03 times of that for smokers. Dust exposure combined with smoking caused significantly higher RR of death of RSD. (4) In male, the death risks of RSD were increased with the amount of smoking per day and years of smoking. CONCLUSION: Occupational dust exposure and smoking may cause excessive lung cancer and NCRSD death with synergistic effects. Smoking has higher RR of Lung cancer death than dust exposure. However, the dust exposure contributes to higher RR of NCRSD death. There is a significant dose-effect relationship between smoking and the death risk of RSD.

目的比較接塵、吸煙對呼吸系統疾病死亡的影響。方法在1989年至1992年廣州建立職業健康監護檔案的基礎上對30歲以上、職業接觸粉塵和無粉塵接觸的80 987名工人進行前瞻性隊列研究。結果(1)隊列平均年齡43．5歲,職業性粉塵接觸率16．3%,吸煙率43．7%,飲酒率33．5%。(2)隊列平均隨訪8年,35人失訪,失訪率0．04%,總死亡1593人中,219人死于肺癌,90人死于非惡性腫瘤性呼吸系統疾病。(3)調整相關因素后,相對于不吸煙者,吸煙者肺癌死亡相對危險度(RR)為3．32,是粉塵接觸者相對于無粉塵接觸者肺癌死亡RR(1．53)的2．2倍。粉塵接觸者非惡性腫瘤性呼吸系統疾病死亡RR為2．41,是吸煙者(1．89)的1．28倍。尤其是矽塵接觸者,其非惡性腫瘤性呼吸系統疾病死亡RR為5．72,是吸煙者的3．03倍。既接觸粉塵又吸煙,呼吸系統疾病死亡RR增加更明顯。(4)男性吸煙者呼吸系統疾病死亡危險分別隨日吸煙量、煙齡的增加而增加。結論職業接觸粉塵和吸煙均可引致超額的呼吸系統疾病死亡,兩者存在協同作用。吸煙致肺癌死亡RR高于接塵,而致非惡性腫瘤性呼吸系統疾病死亡RR則低于接塵。吸煙與呼吸系統疾病死亡危險存在明顯的劑量-效應關系。