A retrospective cohort studyexamined the potential association between exposure to ionizing radiation (exposure) and lung cancer (disease) among workers employed at a uranium mine. The tables below present study data for all participants, and then stratified by smoking status (smokers and non-smokers strata). Answers questions 34-40 using the information presented in the tables below and OpenEpi output provided in the next two pages (Use information from OpenEpi output below the tables. Do not hand calculate estimates).

All Participants (includes smokers and non-smokers)	Radiation +	Radiation -	Total
Lung Cancer +	92	50	142
Lung Cancer -	188	250	438
TOTAL	280	300	580

Smokers only	Radiation +	Radiation -	Total
Lung Cancer +	36	20	56
Lung Cancer -	84	180	264
Total	120	200	320

Non-Smokers only	Radiation +	Radiation -	Total
Lung Cancer +	56	30	86
Lung Cancer -	104	70	174
Total	160	100	260

OPEN EPI OUTPUT (please ignore colors):

2 x 2 Table Statistics Values for Stratum 1 Exposure (+ ) (-) it 36 20 56 Disease 84 180264 120 200320 Values for Stratum 2 Exposure ( + ) (-) 56 30 86 Disease 104 70 174 160 100260 Unstratified (Crude) Values Exposure (+) (- ) + 92 50 142 Disease (- 188 250438 280 300580Risk-Based* Estimates and 95% Confidence Intervals (Not valid for Case-Control studies) Point Estimates Confidence Limits Stratum Type Value Lower, Upper Type 1 Risk in Exposed 30% 22.5, 38.74 Taylor series Risk in Unexposed 10% 6.501, 15.01 Taylor series Overall Risk 17.5% 13.71, 22.06 Taylor series Risk Ratio 3 1.824, 4.9341 Taylor series Risk Difference 20% 10.81, 29.19- Taylor series 2 Risk in Exposed 35% 28.03, 42.67 Taylor series Risk in Unexposed 30% 21.87, 39.61 Taylor series Overall Risk 33.08% 27.64, 39.01 Taylor series Risk Ratio 1.167 0.8088, 1.6831 Taylor series Risk Difference 5% -6.631, 16.63 Taylor series Crude Risk in Exposed 32.86% 27.62, 38.56 Taylor series Risk in Unexposed 16.67% 12.86, 21.32 Taylor series Overall Risk 24.48% 21.15, 28.15 Taylor series Risk Ratio 1.971 1.456, 2.671 Taylor series Risk Difference 16.19% 9.259, 23.12- Taylor series Etiologic fraction in pop. (EFp) 31.92% 18.42, 45.43 Etiologic fraction in exposed(EFe) 49.28% 31.3, 62.55 AdjustedDirectly Adjusted RR 1.626 1.211, 2.1841 Taylor series MH Adjusted RR 1.696 1.271, 2.2631 Taylor series Directly Adjusted RD 14.23% 7.021, 21.44- Taylor series Breslow-Day test for interaction of Risk Ratio over strata: chi square= 8.975 p=0.002737 p is less than 0.05, suggesting that RR differs among strata(interaction). Breslow-Day test for interaction of Risk Difference over strata: chi square= 3.932 p=0.04737 p greater than 0.05 does not suggest interaction. Adjusted RD can be used.Odds-Based Estimates and Confidence Limits Point Estimates Confidence Limits Stratum Type Value Lower, Upper Type CMLE Odds Ratio* 3.839 2.105, 7.1371 Mid-P Exact 2.026, 7.4541 Fisher Exact Odds Ratio 3.857 2.107, 7.0621 Taylor series 2 CMLE Odds Ratio* 1.255 0.7346, 2.1651 Mid-P Exact 0.7117, 2.239 Fisher Exact Odds Ratio 1.256 0.7343, 2.151 Taylor series Crude CMLE Odds Ratio* 2.443 1.653, 3.6371 Mid-P Exact 1.624, 3.7061 Fisher Exact Odds Ratio 2.447 1.652, 3.6241 Taylor series Etiologic fraction in pop.(EFp|OR) 38.31% 23.66, 52.96 Etiologic fraction in exposed(EFe|OR) 59.13% 39.46, 72.41 Adjusted CMLE Odds Ratio* 2.104 1.406, 3.1651 Mid-P Exact 1.38, 3.2281 Fisher Exact Directly Adjusted OR 2.06 1.379, 3.0781 Taylor series Mantel-Haenszel OR 2.048 1.376, 3.047 Robins, Greenland, Breslow Breslow-Day test for interaction of Odds Ratio over strata: chi square= 7.386 p=0.006572 p is less than 0.05, suggesting that OR differs among strata(interaction). *Conditional maximum likelihood estimate of Odds Ratio (P)indicates a one-tail P-value for Protective or negative association; otherwise one-tailed exact P-values are for a positive association. Martin,D; Austin,H (1991) An efficient program for computing conditional maximum likelihood estimates and exact confidence limits for a common odds ratio. Epidemiology 2. 359-362 195% confidence limits testing exclusion of 0 or 1, as indicated LookFirst items: Editor's choice of items to examine first. Results from OpenEpi, Version 3, open source calculator--TwobyTwo Print from the browser with ctri-P or select text to copy and paste to other programs