Research Application Exercise - Question Answer

Research Application Exercise 1
Instructions for completing the exercise:
1. Read the following two articles and use them to answer the following
questions. Use links to Article 1 and Article 2 to access the readings.
2. Note your responses on this document
Wegrzyn, R., et. al. (2017). Rotating night-shift work and the risk of breast
cancer in the nurses' health studies.
American Journal of Epidemiology,
186(5), 532–540.
Article 1 (https:/doi.org/10.1093/aje/kwx140)
Shivappa, N., et. al. (2015). Inflammatory potential of diet and risk of
colorectal cancer: a case –control study from Italy.
British Journal of
Nutrition,
114, 152–158 doi:10.1017/S0007114515001828
Article 2 (https://tinyurl.com/ybkmfy3p)
Question 1:
What study design is the Wegrzyn article?
Answer: The study design is based on data collected from two cohort studies,
which were Nurses Health Study (1988-2012) and Nurses’ Health Study II
(1989-2013).
Question 2:
What area of interest is being addressed in the Wegrzyn article?
Answer: The researchers aim at examining the association between breast
cancer risk and rotating night shift in nurses to find evidence supporting the
statement of circadian disruption being a probable carcinogen.
Question 3:
In the Wegrzyn article what is the total population (n=?) per group
used in the study data?
Answer: In the first Nurses Health Study, the population was n= 78,516
In the Nurses’ Health Study II, the population was n= 114,559

Application Exercise 1
Hence the total population of the study is n= 1,93,075
Question 4:
What is the exclusion criteria of the study population for primary
analysis in the Wegrzyn article?
Answer: Parous women at the baseline were excluded from the study.
Question 5:
Why is exclusion criteria used and why is it important to this or any
study?
Answer: Women nurses bearing offsprings were excluded from the study as
the reported shift work for parous women at baseline could not be attributed
to either pre-pregnancy or post-pregnancy period.
Question 6:
What is a significant finding of the mean ages between the groups
in the Wegrzyn article?
Answer: According to the research findings, the women with 20 years or
more at baseline shift work showed increased risk of breast cancer than the
women with 20 years or more of cumulative shift work.
Question 7:
Why is the answer in question 6 significant to consider with regard
to the overall incidence of breast cancer? (Hint: To answer elements of
this question you will need to find statistical data on breast cancer
https://ww5.komen.org/BreastCancer/Statistics.html)
Answer: The median age of breast cancer diagnosis in the United States is
62. The study result shows that circadian disruption in the female nurses are
leading them to increased risk of breast
Question 8:
Why is hazard ratio used in the study vs risk ratio?
Answer: Hazard ratio shows the instantaneous incidence rates of the risk of
breast cancer in nurses, which would be better indicator to fulfill the
objective the research topic instead of risk ratio which is a ratio of
cumulative risks.
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