Document npzaaz4VVmMJYZyxnb36n12xG

24 ASBESTOS EXPOSURE-SELIKOFF ET AL JAMA, April 6, 19f>4 Table 2.--Total Deaths and Deaths From Cancer of the Lung, Bronchus, Pleura, Mediastinum, and Trachea per 10,000 White Males per Year 1943-1947 A. 1948-1952 A _ 1953-1957 A ---- 1958-1962 A __ Age Total Lung Cancerf Total Lung Cancert Total Lung Cancert Total Lung Cancert 35-39 ................ 36 .... 30 .... 26 .... 25 1 40-44 ................ 55 1 48 1 43 1 42 1 45-49 ................................ 852783723703 50-54 ................ 133 4 124 5 115 6 116 7 55-59 ................ 196 5 189 8 178 10 178 11 60-64 ................ 2957281102761427217 65-69 ............... 435 7 417 11 416 17 418 21 70-74 ................ 634 6 605 11 586 16 607 21 75-79 ............... .............. 9776915108781486617 80-84 .......... 1,453 5 1,353 8 1,346 12 1,363 15 85+ ................. 2,422 3 2,162 7 2,017 9 2,148 11 'Death rates as reported annually by the US National Office of Vital Statistics. A five-year average is given here for each period. Average for 1958-1962 is a projection of 1958-1960, since 1961-1962 rates are not yet available. tDeath rates include cancer of the lung, bronchus, pleura, mediastinum, and trachea, assigned to international list code No. 47b-f prior to 1949 and to No. 160-164 thereafter. is almost always found in the first few years of a prospective epidemiological study of this type. The explanation is almost certainly as follows: The 632 men in this analysis were actively employed as as bestos workers in 1942. Since disability from illness or other causes precludes employment in a trade of this type, these men were presumably well (or at least not disabled) at the start of the study pe riod. Almost any group so selected as to exclude the ill and disabled has a lower death rate during the ensuing few years than does the general popu lation, since ill and disabled persons have extreme ly high death rates. A selective effect of this type gradually wears off with time and largely disap pears within five to ten years from the time of in itial selection. During the second five-year period (1948-1952) the death rate of the asbestos workers was slight ly higher than the death rate of all US white males, ie, 54 observed deaths compared with 50.8 ex pected deaths. In later periods, the death rate of the asbestos workers was proportionately higher. For the period 1953-1957, there were 85 observed deaths compared with 56.6 expected deaths, and for the period 1958-1962, there were 88 observed deaths compared with only 54.4 expected deaths. Table 3.--Observed and Expected Number of Deaths Among 632 Asbestos Workers Exposed to Asbestos Dust 20 Years or Longer Cause of Death Year* ,-----------------------*---------------------- , Total, 1943- 1948- 1953- 1958- 19431947 1952 1957 1962 1962 Total, all causes ............................ 28 Observed (asbestos workers) Expected (US white males).... 39.7 54 50.8 85 56.6 88 255 54.4 203.5 Total cancer, all sites .................. 13 Observed (asbestos workers) Expected (US white males).... 5.7 17 8.1 26 13.0 39 9.7 95 36.5 Cancer of lung and pleura......... Observed (asbestos workers) Expected (US white males).... 6 0.8 8 13 18 45 1.4 2.0 2.4 6.6 Cancer of stomach, colon, and rectum ..................................... 4 4 7 14 29 Observed (asbestos workers) Expected (US white males) .... 2.0 2.5 2.6 2.3 9.4 Cancer of all other sites com bined ....................................... 3 5 6 7 21 Observed (asbestos workers) Expected (US white males) .... 2.9 4.2 8.4 5.0 20.5 Asbestosis ....................................... 0 1 4 7 12 Observed (asbestos workers) Cancer of the Lung, Pleura, and Trachea.--In each of the four five-year periods, far more deaths from cancer of the lung and pleura occurred among the asbestos workers than would have oc curred had their death rates from these diseases been the same as for all US white males (Table 3). Altogether 45 of the 632 asbestos workers died of cancer of these sites, whereas only 6.6 such deaths would be expected from general US experience. Of these 45 deaths, 42 were recorded as due to bronchogenic carcinoma and 3 to neoplasms of the pleura. The pleural neoplasms were all recorded as mesotheliomas. Thus it was found that the death rate from can cer of the bronchus and pleura was 6.8 times as high among these asbestos workers as in the gen eral US white male population (both age and date being taken into consideration). It may be asked whether the high rate of lung cancer among these asbestos workers could pos sibly be attributed to an unusually large proportion of cigarette smokers among them. We cannot an swer this question directly, since we have not yet been able to ascertain die smoking habits of the men who died. However, the following pieces of evidence indicate that unusual smoking habits can not account for the high death rate from lung can cer among these workers: We have interviewed 320 of the 377 surviving members of the 1942 group. Table 4 gives a sum mary of the smoking habits in this group compared with a sample of men drawn from the general population of 1,121 counties in 25 states.7 The un ion sample is somewhat inadequate since it does not include the men who died and does not in clude all of the present living members of the union. Nevertheless, it shows that a substantial proportion of asbestos workers never smoked ciga rettes regularly. Certainly the 632 men in our analy sis of death rates were not all heavy cigarette smokers. In the general male population, lung-cancer death rates are about ten times as high among cigarette smokers as among nonsmokers; and the 144