1. A study to determine factors associated with obesity among health staff will be conducted in all states in Malaysia. One of the study factors was sedentary life style.
a) If you were appointed as collaborator of the research, suggest how you would proceed with the study design and sampling technique.
b) If the study design chosen was a matched case control study
I. State in detail how you would select the control group?
II. A total of 4560 staff were enrolled in the study from all the states in Malaysia and they were divided equally into two groups of case and control. A total of 1750 from the obese group and 450 from control group were found to have a sedentary life style. Construct a two-by- two table.
III. Calculate the odds ratio of those who were obese and had a sedentary life style to those who were obese and had active life style.
IV. Explain why the odds ratio is unable to describe the sequence of events (exposure and outcome) compared to risk ratio.
V. Discuss briefly on how you would plan for the intervention program.
VI. Explain how you would evaluate the intervention program to reduce obesity among the health staff.
2. You have planned a study on diagnostic accuracy of NS1, dengue IgM and IgG serology alone and in combination to diagnose dengue fever in a state of Malaysia.
a) State 2 research questions and 2 objectives for your study.
b) State your study population and justify your answer.
c) State your study design and justify your answer.
d) Write down your research title.
e) Choose one test as reference standard and justify your answer.
f) Choose one combination of approaches (sequential or parallel) that will be used in your study and justify your answer.
g) How do you ensure that the results of your study are valid?
3. Question on ecologic studies. Please refer to the article supplied.
a) Would it be practical to conduct alternative ways of studying the same question (eg, randomized control trial) or was the ecological study the only alternative?
b) Are the subjects in the ecological study representative of the group, place, or population of interest?
c) Were the exposure and outcome variables measured and defined in the same or a similar way across the different populations or groups that are being studied?
d) Have data been collected on important confounding variables that might also explain the exposure-outcome relationship and have they been statistically adjusted for? If data are not available on key factors, is it reasonable to assume that their prevalence is similar in the different groups or populations being compared?
e) Is the identified ecological relationship between the exposure and outcomes biologically plausible and consistent which what is already known about a given topic at an individual-subject level?
f) What is the strength of the quantitative and statistical associations between the exposure and the outcome? The stronger the associations, the greater the likelihood of a true causal relationship.
g) Have the investigators interpreted their data with appropriate caveats? Did they acknowledge the possibility of an ecological fallacy? Were alternative explanations for the association between exposure and outcomes considered by the investigators?
h) Have the study data been collected at multiple levels (eg, individual, physician, hospital, community, or country)? If yes, was multilevel modeling considered or used for analyzing the data?
Article - Pregnancy outcomes and outdoor air pollution: an ecological study in districts of the Czech Republic 1986-8 Martin Bobak, David A Leon