Document kb82v0dnB4rDMEM9Qpg5br1E

LUNG CANCER VOL. 44 177 00d of lung cancer? Further, .s that likelihood in absolute w To answer these questions Jy would require that records of lirette smoking for large numbers of ' sons in the lung cancer age be ,,^nbled. These persons would then "placed in categories with respect to iirette smoking, e.g., nonsmokers, iterate smokers, and heavy smokers. ii|aily they would be observed for a -'cient length of time to determine the Je of lung cancer araonS the various iategories of cigarette smokers and the ^smokers. (Such studies are now ^der way.) ^However, statistical devices have been developed for data such as those in the Present investigation which, if one is to make certain assumptions, Meld an answer to the question, how J'%ijany times does cigarette smoking in crease the likelihood of lung cancer? Application of Cornfield's formula l1,12 to the data from four studies, including the present one (Table 6), indicates that for men aged 50-59 the prevalence of lung cancer is from four to 11 times as great among smokers as among nonsmokers, and from seven to 27 times as great among heavy smokers as among nonsmokers. Similar ratios were found for the 60-69 age group. This formula involves the assumption that in so far as smoking history is concerned, the pa tients are a representative sample of all lung cancer cases and the controls are a representative sample of all other per sons in the general population. Findings on Occupations As noted earlier, the records for lung cancer patient and controls showed all 'Mr ***' Table 7--Twenty Per cent Sample from Complete List of Occupational Groups 1 in Which There Were at Least 5 Cases or 5 Controls Employed for 5 Years or More Occupation Persons Employed in Occupation at Least 5 Years Cases Controls Authors, editors, and reporters Ship captains, mates, pilots, and engineers Clerks, general office Canvassers and solicitors Salesmen to consumers Waiters and waitresses, except private family Policemen and detectives, public service Animal and livestock farmers Farm hands, animal and livestock General woodworking occupations, not elsewhere classified Painters, except construction and maintenance Brick and stonemasons and tile setters Construction occupations, not elsewhere classified Locomotive firemen Attendants, filling stations and parking lots Mechanics and repairmen, not elsewhere classified Note: Semple randomly selected from the 81 occupation groups which met the stated frequencyduration requirements (at least 5 cases or 5 controls with 5 years or more employment). Occupa tions classified according to 3-digit categories in the Dictionary of Occupational Titles (2nd ed.). Washington, D. C.: U. S. Employment Service, 1949.