Assignment -

QUESTIONS 1 to 6 refer to the study by Chan et al., 2011 Red and processed meat and colorectal cancer incidence: meta-analysis of prospective studies (attached).

QUESTION 1: Figure 2 of Chan et al., meta-analysis depicts a forest plot illustrating the dose-response meta-analysis of total red meat and processed meats consumption and risk of colorectal, colon and rectal cancers.

a) Which individual study or studies included in this meta-analysis reported a beneficial association between total red and processed meats consumption and risk of colorectal cancer? (please list the study/studies by authors last name and year, like in the forest plot).

b) How many studies reported statistically significant adverse associations (increased risk) between total red and processed meats consumption and risk of colorectal cancer?

QUESTION 2: In all the forest plots we can see that some of the studies included in the meta-analysis reported narrower confidence intervals (and thus greater precision) than others, and these studies typically had a higher weight assigned to them (as depicted by the size of the square symbols).

What is generally the reason behind the relatively wider confidence intervals (and thus lower precision) in some studies compared to others?

QUESTION 3: Systematic reviews are not free of biases. In their results the authors reported that the only evidence of publication bias was in the studies on processed meat and colon cancer, noting that small studies with inverse associations were missing. When present, publication bias with these characteristics is most likely to lead to: (multiple choice: select 1 answer only)

a) Confounding of the association between an exposure and an outcome.

b) Lack of an association between an exposure and an outcome.

c) Over-estimation of the association between an exposure and an outcome.

d) Under-estimation of the association between an exposure and an outcome.

e) It does not impact the magnitude of the association between the exposure and an outcome.

QUESTION 4: The assessment of the quality of individual studies selected is one of the essential steps that should to be carried out while conducting a systematic review of the literature. Chan et al did not perform such quality assessments in their meta-analysis, however. Which of the following instruments the authors could have had used for this purpose? (multiple choice: select 1 answer only)

a) The JADAD scale

b) The Newcastle-Ottawa Scale

c) The CONSORT statement/checklist

d) The PRISMA statement

e) The Cochrane tool

QUESTION 5: What potential sources of heterogeneity did the authors explore in this study?

QUESTION 6: Based on the findings of this meta-analysis, if reducing red and processed meats was targeted as a prevention strategy in the general population, what level of prevention would this be considered to be? Please select the best answer from multiple choices AND write 1-2 sentences of justification.

a) Primary

b) Secondary

c) Tertiary

d) High risk

e) Effective

QUESTION 7: You wish to evaluate a new screening test that has become available for an infectious disease that results in chronic health problems if left undiagnosed. Results from your evaluation found that of the 1448 people with a positive test result, 797 were subsequently confirmed to have the infectious disease. Among the 10,892 people with a negative test result 129 were later diagnosed with the infectious disease.

a) What is the sensitivity and specificity (i.e. accuracy) of this test? (Note: please show your 2x2 table and calculations to receive full marks)

b) Five years after the successful implementation of the screening test (mentioned above), early intervention has reduced the spread of infection and the prevalence of the disease has reduced to 1.2%. Assuming the sensitivity and specificity of the test remain the same, what will happen to the performance of the test in this population now (compared to 5 years ago).

(Note: to receive full marks for this question please show any supporting calculations as well as a comparison to test performance 5 years prior in your response).

c) An epidemiologist wants to trial the efficacy of a new vaccination for the infectious disease (mentioned above). He wants to ensure that only participants who are currently free of the infectious disease are enrolled in the trial. He therefore screens a large group of potential participants using the screening test (mentioned above). Based on the outcome of this test, he decides who is eligible to participate (free of disease) in the vaccination trial. For this purpose, it is very important that the diagnostic test have a high: (multiple choices: select 1 answer only)

a) Sensitivity

b) Specificity

c) Positive predictive value

d) Negative predictive value

e) All of the above

d) After successful clinical trials of the vaccination, the State government wishes to implement a new vaccination program to prevent the infectious disease (and the subsequent health problems associated with it) in your State. Your primary outcome to assess efficacy of the vaccination in your State should be (multiple choice: select the most appropriate answer only):

a) The prevalence of the uptake of the vaccination by the population

b) The odds ratio/relative risk between the infectious disease and subsequent chronic health problems

c) The prevalence of the infectious disease in the State

d) The mortality rate of the infectious disease in the State

e) The incidence rate of the infectious disease in the State

QUESTION 8: If the incubation period for an infection is shorter than the latent period for infection, which of the following is likely to occur? Please select 1 option from the following AND briefly justify your answer.

a) People may pass on the infection before they become sick

b) People will become sick before they can pass on the infection

c) An epidemic is likely to occur

d) The disease will not be passed on to others

e) The disease is likely to be endemic in the population

QUESTION 9: The Government decides that it is necessary to monitor the rates of gestational diabetes mellitus (diabetes during pregnancy) occurring in pregnant women. They randomly select a number of antenatal clinics from across the country and set up oral glucose tolerance testing facilities, which report any positive test results back to the government epidemiologist. This type of surveillance is best known as:

a) Passive surveillance

b) Active surveillance

c) Sentinel surveillance

d) Syndromic surveillance

e) Process surveillance

QUESTION 10: Which of the following statements is correct? The attributable burden of a disease due to a given risk factor is: (Note: Please justify your answer to receive full marks)

a) Avoidable

b) Unavoidable

c) Unpredictable

d) Always larger than the burden due to other risk factors

e) Always smaller than the burden due to other risk factors

QUESTION 11: Australian law prescribes that all cigarettes sold in Australia need to be packaged without brand logos and related art work on the outside of the pack (also known as 'plain packaging'). This is an example of a: (Note: please justify your answer to receive full marks)

a) Tertiary prevention strategy

b) Secondary prevention strategy

c) High-risk prevention strategy

d) Mass prevention strategy

e) None of the above

QUESTION 12: You are working as an epidemiologist in a country where domestic violence has been identified as a significant issue. The National Government of the country is looking to fund a prevention strategy to reduce the prevalence of domestic violence. As funding is limited, they have asked for your advice to help them prioritise possible prevention strategies to reduce the public health burden of domestic violence.

You identify a case-control study that has been previously conducted in your country, which examines some of the risk factors for domestic violence. Based on the data provided (see Table below), you need to prioritise the risk factors in order of which should be given funding priority to make the biggest impact on the public health burden of domestic violence (where 1 is the risk factor with the biggest impact, and 3 is the risk factor with the smallest impact). You will need to estimate the proportion of domestic violence cases in the population that are attributable to each of the risk factors to justify your answer.

(Note: For full marks in your answer, please provide: 1. The order of how you would prioritise risk factors for funding prevention interventions and 2. The calculations you used to come up with this order. Also note, for the purposes of this exercise assume that all risk factors act independently of one another when used as prevention strategies).

Attachment:- Reading File.rar