PUBH 350 Assignment 3 Name: ____________________________________ Questions 1-6 refer to the following information: A study followed 900,000 US adults from 1992 to 2008. At baseline, all participants were screened and determined to be cancer free and their body mass index (BMI) was calculated. Body mass index is a measure of obesity that is calculated using a person's height and weight. Subjects were separated into the following groups according to their BMI: (a) normal weight, (b) slightly overweight, (c) moderately overweight and (d) greatly overweight. 57,145 deaths from cancer occurred in the population during the follow-up period. 1. What type of study is this? 2. Use the data given above to calculate the cumulative incidence of deaths from cancer among the study population over the follow-up period. 3. What additional information would need to be provided for you to be able to calculate the incidence density of cancer deaths? 4. The following results were seen for men and women when the heaviest members of the cohort were compared to those with normal weight: Men: Relative Risk of Cancer Death = 1.5 (95% CI: 1.1-2.1) Women: Relative Risk of Cancer Death = 1.6 (95% CI: 1.4-1.9) State in words your interpretation of the relative risk given for men 5. To show the public health impact of obesity on cancer mortality in the total population, the authors stated that 90,000 cancer deaths could be prevented each year in the total US population if adults could maintain normal weight. What measure of association is being described? 6. Using what you know about necessary and sufficient causes of disease, as well as general knowledge about cancer, answer True or False to the following statements: a. Being greatly overweight is a necessary cause of cancer mortality _____ b. Being greatly overweight is a sufficient cause of cancer mortality _____ 7. Of 2,872 persons who had received radiation treatment in childhood because of an enlarged thymus, cancer of the thyroid developed in 52. A comparison group consisted of 5,055 children who had received no such treatment (they were brothers and sisters of the children who had received the radiation treatment). During the follow-up period, none of the comparison group developed thyroid cancer, but benign thyroid tumors developed in 6. Fill in the 2x2 table for this problem and calculate the relative risk for benign thyroid tumors. (Show your work) Exposur e Yes No Total Disease Yes N o Total Questions 8 and 9 refer to the following information: The results of a 10 year cohort study of smoking and coronary heart disease (CHD) are shown in the following table: At Beginning of Study 2,000 Healthy Smokers 4,000 Healthy Non-Smokers Outcome After 10 Years CHD CHD Did Develope Not d Develop 65 1,955 20 3,980 8. What is the incidence of CHD in smokers that can be attributed to smoking? (Give your answer per 1,000 smokers) 9. What is the proportion of the total incidence of CHD in smokers that is attributable to smoking? Questions 10 and 11 are based on the following information: In a cohort study of smoking and lung cancer, the incidence of lung cancer among smokers was found to be 9 per 1,000 and the incidence among non-smokers was 1 per 1,000. From another source we know that 45% of the total population were smokers. 10. What is the incidence of lung cancer that is attributable to smoking in the total population? (Give your answer per 1,000) 11. What is the proportion of the risk in the total population that is attributable to smoking? 12. In a case-control study to study the effects of alcohol on esophageal cancer there were 200 cancer cases and 775 community controls selected to participate in the study. Of the 200 esophageal cancer cases, 96 were exposed to more than 80 grams of alcohol per day; whereas of the 775 controls there were 110 who were exposed to more than 80 grams of alcohol per day. Fill out the 2 x 2 table below and calculate the odds ratio for the relationship between alcohol consumption and esophageal cancer. Exposure: More than 80 grams of alcohol per day Yes No Total Esophageal Cancer Cases Controls Total 13. Calculate the matched-pair odds ratio from the following case-control study evaluating heart disease and cigarette smoking. Cases 20+ cigs/da y <20+ cigs/da y Total Controls 20+ <20+ cigs/da cigs/da y y 2 36 Total 38 8 34 42 10 70 80 14. Using the information above, calculate the unmatched odds ratio from the pairmatched case-control study evaluating heart disease and cigarette smoking. Fill in the following table with the unmatched numbers and then complete the odds ratio calculation. (Hint: There is an example of this in the slides we talked about in class, compare the matched and unmatched tables in the example to fill out the unmatched table in this question, then complete the calculation) Exposure: 20+ cigs/day Yes No Total Heart Disease Case s Control s Total