Document ZJnVwwrzxeepOgz2GYeOMJaX7

I c, 1964 Vol 188, No 1 ASBESTOS EXPOSURE-SELIKOFF ET AL 25 a Table 4.--Smoking Habits of 320 Abestos Workers Exposed to Asbestos Dust 20 Years or Longer Compared With Sample of Men From the General Population Cancerf 1 1 3 7 11 17 21 21 17 15 11 Average b-f prior ra.--ln ieaths airred 'e oceases Ie 3). ed of eaths ence. je to f the rded j'. K-' can is as gendate [ I lung r pos- i tion an- *.y- yet the ! of f an- f an- ing im- red :ral an>es in- | he ial ;aly- Si te er lg { le I Age 40-49 50-59 60-69 70+ Never Smoked Regularly Asbestos Workers, % 9.3 14.3 20.3 25.5 General Population, % 18.8 19.9 23.6 37.1 Smoked Pipe, Cigar, Never Cigarettes Asbestos Workers, % 4.6 6.1 10.1 11.8 General Population, % 7.5 9.9 16.2 23.9 *Sample of men from general population as reported by Hammond and Garfinkel.7 History of Cigarette Smoking Asbestos Workers, % 86.1 79.6 69.7 62.7 General Population, % 73.7 70.2 60.2 39.0 death rate from lung cancer increases greatly with the amount of cigarette smoking.8 However, a large proportion of all men in the United States have a history of regular cigarette smoking. From data in a prospective study on smoking,8 it may be esti mated that if all men smoked a pack or more of cigarettes a day (ie, if all the nonsmokers, cigar smokers, pipe smokers, and light cigarette smok' efs hid, instead, been heavy cigarette smokers) the lung-cancer death rate would be approximately 3.4 times as high as it is at this time. From this we may conclude that even if all our asbestos workers had smoked a pack or more of cigarettes a day (and, indeed, from our sample we know they did not), and if exposure to asbestos were of no significance, then their lung cancer death rate would have been about 3.4 times as high as the rate in the general US male popula tion. Clearly, the smoking habits of the asbestos workers cannot account for the fact that their lungcancer death rate was 6.8 times as high as that of white males in the general population. Gastrointestinal Cancer.--Rather to our surprise, the death rate from cancer of the stomach and the death rate from cancer of the colon and rectum were higher among the asbestos workers than would be expected from the rates reported for the US white male population, calculated in the same way as for lung cancer. Twelve deaths from gastric cancer occurred among the asbestos workers, as compared with only 4.3 expected. Seventeen deaths from cancer of the colon and rectum occurred among the asbestos workers, as compared with 5.2 expected. Cancer of All Other Sites--The combined death rate from cancer of all sites other than lung and pleura, and stomach, colon, and rectum was not increased. Twenty-one such deaths occurred among asbestos workers, as compared with 20.5 expected. Asbestosis.--Of the 255 deaths, 12 were due to asbestosis (pulmonary insufficiency, cor pulmo nale). The lapsed time from first asbestos exposure to death from asbestosis averaged 45.8 years, with a range of 32 to 59 years. Comment Carcinoma of the Lung.--The results with regard to carcinoma of the lung are clear. Industrial ex posure to asbestos by insulation workers, as stud ied here, residts in a marked increase in the inci dence of cancer of the lung, approximately six to seven times the expected incidence. Altogether, 45 (17.6%) of 255 men with more than 20 years elapsed since the onset of exposure died of cancer of the lung or pleura. These data do not give the "incidence of cancer of the lung in asbestosis." They relate to the spe cific condltinns of 9W investigation: to a group of men with only intermittent exposure to materials ' containing limited amounts (often 2% to 20%) of asbestos under working conditions varying from very dusty, as in extracting old insulation in closed quarters, to those with little dust exposure, as in building construction in open air. Moreover, they relate to the relatively recent past, in a trade with the shorter work week of the strong building trades unions, in an era when industry has been aware of potential asbestos hazard and the working popu lation has had some consciousness of potential risk associated with dust exposure. These data would not necessarily apply to asbestos exposure in other industries, such as the factory production of asbestos products, the asbestos textile industry, etc, where conditions of employment might be quite different. Our results do not contradict the even higher incidence of lung cancer suggested in other studies3; they are merely a shade less strik ing. Diffuse Pleural and Peritoneal MalignancyMesothelioma--Determining the incidence of dif fuse pleural mesothelioma is complicated by the insecurity of its histological verification. While some pathologists will so categorize a high propor tion of diffuse pleural tumors, in the experience of others it is a veiy rare tumor and may be mim icked by anaplastic peripheral carcinoma of the lung and diffuse fibrosarcoma of the pleura. It is difficult to evaluate completely the published re ports of diffuse pleural mesothelioma in asbestosis in the absence of complete details of each case. To the present time, there has been no informa tion concerning the incidence of diffuse pleural mesothelioma in asbestosis, since the published cases are reported without reference to a total pop ulation in which they occur. Nevertheless, the