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What is thecrude incidence rate ofCHD ininactivemenand inactive women”

What is the crude incidence rate of CHD, ininactivemenand inactive women”

This assignment is based on the learning objectives and concepts in weeks 3-7, but may also require knowledge from Topic1st and 2 week. There are a total of50marks and this assignment will contribute30% towards the total assessment for this subject.

Your assignment should be typed, with adequate space left between questions.Assignments should be submitted via vUWS (see specific instructions relating to Assignment2 on the401076vUWS web-site).

Be as brief as possible in your answers. No answers need to be longer than a few short sentences or short paragraphs. Please note this is an individual exercise.

Re-submission will not be permitted.

Late assignments will not be accepted without prior approval- use special consideration e-form

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Assignment Cover Sheet

School of Science & Health

Student name:
Student number:
Unit name and number: 401076
Tutorial group:
Tutorial day and time:
Unit Coordinator: Professor Dafna Merom
Title of assignment:
Date due:
Date submitted:
Campus enrolment:

?I hold a copy of this assignment ifthe original is lost or damaged.

?I hereby certify that no part of this assignment or product has been copied from any other student’s work or from any other source except where due acknowledgement is made in the assignment.

?I hereby certify that no part of this assignment or product has been submitted by me in another (previous or current) assessment, except where appropriately referenced, and with prior permission from the Lecturer/Tutor/ Unit Co-ordinatorfor this unit.

?No part of the assignment/product has been written/produced for me by any other person except where collaboration has been authorised by theLecturer/Tutor/Unit Co-ordinator concerned.

?I am aware that this workwill be reproduced andsubmitted to plagiarism detection software programs for the purpose of detecting possible plagiarism(which may retain a copy on its database for future plagiarism checking).


Note: An examiner or lecturer/tutor has the right to not mark this assignment if the above declaration has not been signedQuestion 1:

Read the following paper, and answer the questions below:

Sundquist,K. Qvist,J.Johansson,S. Sundquist,J. “The long-term effect of physical activity on incidence of coronary heartdisease: a 12-year follow-up study”

(a)“Whatstudy design does this study employ”?[1point]

(b)“Find the methodological aspectsmentioned in the paper that convinced you thatis the type of study design, please use dot points”[2points]

(c)“What justification do the authors give for conducting this study, please use dot points”?[2points]

(d)“Whatwas the proportion of those who (i) do not do any physical activity (ii)engaged in twice a week vigorous physical activity”? (You are not required to report 95% confidence intervals)[2points]

(e)“What is thecrude incidence rate ofCHD ininactivemenand inactive women”?[2points]

(f)“What is thecruderelative risk ofbeing non-active versusbeing “highly active”(vigorous physical activity at least twice a week)in men and in women”[2points]


(g)“How would you interpret therelative risk in the above section” (f)?[2 marks]

(h)“Looking at thesex and age adjusted RR in Table 3 (the RR ismeasured by the Hazard Ratio which issimilar)(i) how would you describe the association between physical activity and CHD” [4points]

(i)“The authors removed from the analysisany person who self-rated their health as “bad” or “anywhere between good and bad” why? (one sentence[2 points]

(j)“What possible bias could have changed the estimate for the association between physical activity and CHD –mentionat least one, and explain why” [2 points]

(j)“Do you think this research adequatelyaddressed confounders? Justify your answers{no more than 60 words}” [2 points]Question 2:

“Researcher wanted to know whether there is an association between use of certain drug (Reserpine) and breast cancer. Their target population was 2 million women, 1 million from low socio-economic status (SES) and 1 million from high SES. The prevalence of breast cancer in this population and the use of Reserpine is documented bellow”

High SES Low SES
Breast cancer prevalence 20 per 100,000 20 per 100,000
Resperine 800 per 10,000 200 per 10,000
a) What is the study design, justify? [2Points]

b)“Build the 2X2 tableconsist with dataabove. To be able to fill in the cells you have to assume that there is no association between the use of Reserpine and breast cancer. In other word the prevalence of breast cancer is similar among drug users and non-drug users and this is true in both high and low SES.Hint: to help you fill in the data you must start with the number that appears in the Table marginal total columns and rows”.[4 points]

High SES Low SES
Breast Cancer No breast cancer Breast Cancer No breast cancer
Use Reserpine.
Non-users of Reserpine
“Now assume that the association with Reserpine was evaluated in a follow up study and the investigators found that the incidence rate of breast cancer amongwomen who used Reserpinewas 3 timeshigherthan among women who did not use Reserpine. Stratum specific analysis showed that this was true for both high and low SES”.

“If Reserpine is causally related to breast how many cases of breast-cancer could be avoided in the high SES and Low SES had Reserpine would be banned from being in the market? (in other words what is the PAF?)”[3 points]

Question 3

“A new drug to lower blood pressure(BP)is being tested. The results of the RCT are displayed below”:

Lowered BP No change in BP
Drug 70 30 100
Placebo 40 60 100

“There was a speculation, that the drug may not be as effective in overweight individuals as in normal weight. The results wasstratifiedby weight status and are presented bellow”

Over-weight Normal weight
BMI >= 25 BMI

No change in BP Lowered

No change in BP
Drug 30 20 Drug 40 10
Placebo 20 30 Placebo 20 30
a)“Calculate the crude measure of association between the drug and blood pressure [2 points]”

b)“Calculate the stratum specific association between the drug and blood pressure [2 points]”

c)“Interpreted your findings[2 points]”

Question 4

“A case –control study was carried out in which 120 of 200 people with type 2 diabetes and 50 out of 200 control people reported a history of sleep –disorders breathing. In further analysis, the investigators noticed that 50% of the cases but only 25% of the controls were men. Could this difference induce a bias? Explain your answer. What would be a practical way to avoid such differences in case control studies?” [4 points]

Question 5

“Which of the following terms associated with selection bias? [2 points]”

a)Chance.b)Confounding.c)Response rated)Validity

“Explain your choice in one sentence”

Question 6

“Which of the following term is associated with measurement bias? [2points]”

a)Effect Modificationb)Confounding.c)Response rated)Validity

“Explain your choice in one sentence”

Question 7

“What biases would you suspect in a survey of the prevalenceof drug useamong young people using a representative sample of students attending high school justify (not enough to name the biases(No more than 60 word)” [4 points]