REQUIRED ASSIGNMENT 2: Article Critique
Using the Watters et al. article Alcoholic Beverages and Prostate Cancer in a Prospective US Cohort Study, answer the following questions. Answers should be submitted in Canvas Webcourses by April 6, 2015 at 12:00 pm (noon) by following the submission link under the Module called Required Assignment 2: Article Critique. No paper submissions will be graded. Answers will be submitted just like the study design required assignment. You may enter the answer submission quiz up to THREE times prior to the due date. I recommend recording your answers on this assignment first, and then transferring them to Web courses. Since we are discussing this assignment in class later on the day it is due, no late assignments will be accepted unless you miss class on April 6 for an emergency with acceptable documentation. All other late assignments will receive a score of zero. All questions are worth one (1) point unless otherwise noted.
1. Which of the following is not part of the initial background or rationale provided by the authors to justify the need for their study?
a. Although there have been more than 60 studies of this association, the results are inconsistent, and several critical gaps remain to be addressed using prospective data with sample sizes sufficient to detect small to modest associations, including whether the effect of alcohol differs by prostate cancer stage, how patterns of alcohol consumption influence risk, and alcohols role in fatal prostate cancers.
b. One case-control study reported a protective association between prostate cancer incidence and red wine .
c. Alcoholic beverages have been identified as known human carcinogens, with several biologically plausible mechanisms that may influence prostate cancer risk.
d. The report by the World Cancer Research Fund on nutrition, physical activity, and cancer concluded that the data were too limited to determine an association between alcohol and prostate cancer.
2. Who comprised the study population for the current study?
a. Participants in the NIH-AARP Diet and Health Study
b. Patients in the Social Security Administration Death Master File in the United States
c. Patients in 11 state cancer registry databases
d. None of the above
3. What study design was used?
a. Case-control
b. Cross-sectional
c. Ecological
d. Cohort
4. What is the primary dependent variable?
a. Wine consumption
b. Prostate cancer
c. Beer consumption
d. Liquor consumption
5. How did the authors determine whether or not participants had prostate cancer at baseline?
a. Laboratory exam
b. Self-report via questionnaire
c. Medical record review
d. They did not determine whether or not participants had prostate cancer at baseline
6. Type in the major categories for the prostate cancer variable. (3 points)
Nonadvanced, Advanced, and Fatal are the major categories for the prostate cancer variable.
7. Which of the following citations was used to categorize portion sizes and nutrients?
a. Platz, ES, Leitzmann MF, Michaud DS, et al. Interrelation of energy intake, body size, and physicial activity with prostate cancer in a large prospective cohort study. Cancer Res. 2003; 63(23):8542-8548.
b. Velicer CM, Kristal A, White E. Alcohol use and the risk of prostate cancer: results from the VITAL Cohort Study. Nutr Cancer. 2006;56(1):50-56.
c. Dennis LK, Hayes RB. Alcohol and prostate cancer. Epidemiol Rev. 2001;23(1):110-114.
d. Tippett KS, Cypel YS. Design and Operation: The Continuing Survey of Food Intakes by Individuals and Diet and Health Knowledge Survey, 1994-96. Continuing Survey of Food Intakes by Individuals, Nationwide Food Surveys. Washington, DC: Agricultural Research Service, US Department of Agriculture; 1997.
8. Type in the first five (5) confounders/covariates (i.e. risk factors) that were included in the final multiple regression model? (5 points)
9. Go to Table 1. Type in the correct numbers into a shortened version of the table below. Reproduce the numbers exactly as they are in the article table. (12 points)
Table 1. Selected Characteristics According to Alcohol Consumption Among Men in the NIH-AARP Diet and Health Study, 1995-2003 (n=294,707).
Using the abridged version of Table 1, answer the following questions.
10. There is a statistically significant difference in median age between the four exposure categories.
a. Yes
b. No
c. Cannot determine
11. Marital status is likely to be a confounder of the association between alcohol consumption and prostate cancer.
a. Probably
b. Probably not
c. Cannot determine
12. Heavier drinkers were less likely to report a history of diabetes than lighter or non-drinkers.
a. Yes
b. No
c. Cannot determine
13. Go to Table 2. Fill in the numbers from the article in the abridged version of the table below. Reproduce the numbers that should go in place of the red X exactly as they appear in the article table. (8 points)
Table 2. Relative Risk of Prostate Cancer in Relation to Daily Alcohol Consumption Among Men in the NIH-AARP Diet and Health Study, 1995-2003.
Use the data from the abridged Table 2 to answer the questions below. Thus, all questions refer to results from the fully adjusted model.
14. How many covariates were included in the fully adjusted regression model? Assume PSA screening and DRE were included as one summary variable.
8 covariates were included in the fully adjusted regression model.
15. What alpha (?) level was used in this study?
The alpha (?) level was used in this study is 5%, i.e. 0.05.
16. The HR for 0 drinks per day is 1. What does this mean?
a. There is no association between not drinking and prostate cancer
b. Zero drinks per day was used as the reference or comparison group
c. It is an error
d. Cannot determine
17. There is evidence of a dose-response trend associated with increasing drinks per day among both non-advanced and fatal cases.
a. Yes
b. No
c. Cannot determine
18. Overall, the risk of prostate cancer increased as the number of alcoholic drinks consumed per day increased among non-advanced cases.
a. Yes
b. No
c. Cannot determine
19. Look at the HR for non-advanced cases who drank >3-<6 alcoholic drinks per day. This result is statistically significant. a. Yes b. No c. Cannot determine 20. Overall, the risk of prostate cancer increased as the number of alcoholic drinks consumed per day increased among fatal cases. a. Yes b. No c. Cannot determine 21. Look at the HR for fatal cases who drank >3-<6 alcoholic drinks per day. This result is statistically significant. d. Yes e. No f. Cannot determine 22. As briefly as possible, explain why you think we observe a different pattern of results for non-advanced cases compared to fatal cases. When making an overall conclusion about this study (does alcohol consumption impact risk of prostate cancer?), which groups results would you feel most comfortable using (non-advanced, advanced, or fatal prostate cancer)? Explain. (5 points)