MORTALITY OF IRON MINERS IN LORRAINE (FRANCE) - RELATIONS BETWEEN LUNG-FUNCTION AND RESPIRATORY SYMPTOMS AND SUBSEQUENT MORTALITY

An increased mortality from lung and stomach cancer was found in previ ous studies on Lorraine iron miners. A detailed analysis, however, was not possible due to the lack of data for survivors. In this study the cohort included 1178 workers selected at random from all the 5300 wor king miners aged between 35 and 55 at the start of the follow up perio d, which ranged from 1975 to 1985. Occupational exposures and tobacco consumption, lung function tests, and respiratory symptoms were assess ed for each subject in 1975, 1980, and 1985. This study confirmed the excess of lung cancer (standardised mortality ratio (SMR) = 389, p < 0 .001) and of stomach cancer (SMR = 273, p < 0.05). There was no excess of lung cancer in non-smokers and moderate smokers (<20 pack-years) o r the miners who worked only at the surface or underground for less th an 20 years. A significant excess (SMR = 349, p < 0.001) was found in moderate smokers when they worked underground for between 20 and 29 ye ars. Heavy smokers (over 30 pack-years) or subjects who worked undergr ound for more than 30 years experienced a high risk: SMR = 478 (p < 0. 001) for moderate smokers who worked underground for over 30 years; 58 8 (p < 0.001) for heavy smokers who worked underground for between 20 and 29 years; and 877 (p < 0.001) for heavy smokers who worked undergr ound for over 30 years. This showed an interaction between smoking and occupational exposure. The excess mortality from lung cancer was beca use there were some subjects who died young (from 45 years old). Compa rison with the results of a previous study showed that additional haza rds produced by diesel engines and explosives increased the mortality from lung cancer. The SMR was higher than 400 (p < 0.001) from 45 year s old instead of from 56 years. A relation was found between a decreas e in vital capacity (VC), forced expiratory volume in one second (FEV1 ) and of FEV1/VC and mortality from all causes and from lung cancer in heavy smokers or men who had worked underground for more than 20 year s. Respiratory symptoms were related to mortality from lung cancer amo ng smokers (moderate and heavy) who worked underground for more than 2 0 years. It is considered that the risk of lung cancer in the Lorraine iron miners was mainly due to dust, diesel engines, and explosives al though the role of low exposure to radon daughters could not be totall y excluded.