Second Session Epidemiology

Chapter 9- Introduction to Descriptive Epidemiology

1) What is not the uses of descriptive study?

a- generate hypothesis or generalization

b- Allocation for resource and utilization

c- Pattern and trend

d- Determine health related states

Answer: The used of descriptive study is formula [G.A.P]- Generate hypothesis, allocation, and Pattern. The determine health related states is analytic in which it test the hypothesis

2) Why do increasing age will increase the mortality?

Answer: Because as age increasing, formula [E.S.R]- Exposure, Susceptibility and Response also increase.

3) Which is true for Sexually Transmitted Disease?

a- Same Exposure, Different susceptibility

b- Different Exposure, Same susceptibility

c- Different Exposure, Different susceptibility

d- Same Exposure, Same susceptibility

Answer: B- Follow the formula Exposure are different but the susceptibility the same

4) Which of the following have same exposure but different susceptibility?

a- Flue

b- Injury

c- STD

d- Diabetes

Answer: A- Same explanation

5) What is epidemiological variable?

Answer: It include time, place and person

6) How do you classify person?

Answer: It can be either acquired and inherited. (e.g. Inherited: Age, Sex +Culture) (e.g. acquired like lifelong: literacy, civil status and non-lifelong: Socioeconomic Status)

7) What effect Sex?

Answer: anatomy, biology, X-genetic+hormonal (Abx)

8) What effect culture?

Answer: Practice and genetic

9) Explain the socioeconomic status?

Answer: It can be explained by breeder theory a drift hypothesis. In breeder hypothesis, lower class contribute to development of disease. While in drift hypothesis, people with ow health downward drift of socioeconomic status.

10) Which of the following explain non-lifelong acquired person characteristic?

a- Twin Study

b- Migrant study

c- Case report

d- A and B

Answer: D- In twin study, investigate the uniqueness of environment of study, while in migrant study, it investigates stomach cancer among migrant Japanese. Both of this study is example of non-lifelong, acquired person characteristic of epidemiological variable.

11) What different type of epidemiology in term of place?

Answer: Among country, within country, and localized. It also can be described in endemic (naturally occurred), epidemic (excess) or pandemic (other country).

12) Which of the following example of pandemic become endemic?

a- Dengue

b- Avian Influenza

c- HIV

d- Ebola

Answer: C- HIV is example of previously pandemic from Africa and becoming endemic of most of the country.

13) What is the different between spatial and temporal cluster?

Answer: Spatial are cluster in specific region while temporal is cluster in specific time. But both occurred in cluster occurrence in excess (cluster) in comparison with sporadic.

14) What different type of time?

Answer: Point, cyclical, and secular. In epidemiological graph, it usually records the number and not disease frequency.

15) What is Ecological Fallacy and Simpson paradox?

Answer: Ecological fallacy is when conclusion drown by the group is not applicable/ true to that individual level. Simpson paradox is when correlation of individual when combine will create totally opposite and wrong conclusion.

Chapter 10- Descriptive Study

1) Which of the following is not descriptive study?

a- Case series

b- Case report

c- Ecological study

d- Cross sectional study

Answer: Cross Sectional study is analytical but cross-sectional survey is descriptive study.

2) Which of the following true about correlation study?

a- It also known as ecological study

b- It is community as it is unit of observation and unit of analysis

c- It is observational Study

d- It is analytic study

e- All are true

Answer: Correlation study or ecological study is a study that use community as its unit of observation and analysis. It falls under observational study in the observational-analytic spectrum.

3) Which of the following is not the variable for ecological study?

a- aggregate measure

b- global measure

c- environmental measure

d- time measure

Answer: D- All three aggregate, global and Environmental is the variable or aggregate- level for ecological study except for time.

4) Write the different classification of ecological study?

Answer: time-trend, multiple group, mix method [or] exploratory, analytical.

These can be cross and produced (3X2) = 6 classification.

5) If given Y-axis: Incidence of Depression, X-axis: Years, Y-axis: Age standardization, and two graphs plotted for male and female. What kind of ecological study is this?

Answer: Mix Method Etiological because multiple group+ Time + Etiology (Age standardization)

6) What is ecological felony?

Answer: It is aggregate bias where finding of the group may not be true for individual. It can be seen as type of co-founding. This mean that this is systematic error (Bias+CoFounding).

Chapter 11- Cross Sectional Study

1) What are the features of cross-sectional study?

Answer: It is observational, cross sectional study. Which mean that no intervention between exposure and outcome and all the record taken at time of start of the study.

2) What is first step for cross sectional study?

Answer: Both Exposure and outcome is taken simultaneously in its source population

3) How do you compute for cross sectional study?

Answer: Prevalence Ratio (Open) and Prevalence Proportion (Close). In addition, there also Prevalence difference. Hence, PR, PP, PD

4) What do you mean by 1.5 PR and PD?

Answer: Prevalence of Exposure is 1.5 higher than unexposed. For every 1 person, there is 1.5 more cases in exposure compare to unexposed.

5) Explain the advantage of cross-sectional study?

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Over cohort: it is cheaper, less time to conduct and low follow-up and dropout

Over case-control: It yield more generality and less recall bias

6) Explain the disadvantages of cross-sectional study?

Answer: [rol + €] It not useful in rare disease, and disease of long induction/incubation period. It cannot give cause-effect relationship.

Chapter 12- Cohort Study

1) What are the features of cohort study?

Answer: It is longitudinal, prospective and observational study. Longitudinal because exposure and outcome were collected different time period. Prospective because it looks forward at the direction of inquiry, and observational because no assignment to the group of exposure/outcome.

2) What is the first step in cohort-study?

Answer: Selecting the cohort group. Criteria to select include formula [F-A-CE] Free from disease, Alive, Characteristic not Extreme. It is can either general, special. For comparative group either internal or external.

3) How do you compute for cohort study?

Answer: Can be compute for Relative Risk, Risk Different, Attributable Fraction, and Attributable Number, Incidence proportion, Incidence Ratio (Density), Incidence proportion(cumulative) (RR, RD, AF, AN, IR, IP). For RR cross multiplication (Same like OR). RD= IE-Ie., AF= (IE-Ie)/IE and AN= AF= AFxN.

4) Suppose you were given 2.1, what it means for RR, RD, AF and AN?

Answer: RR- Exposure is 2.1 more likely to get disease than unexposed. RD- For every one person, there 2.1 more exposure group compare to unexposed group. AF-Among those expose 210% of the disease is due to exposure itself. AN- For every 21-person disease is attributable from the exposure.

5) Explain what the advantage of cohort study?

Answer: Over case-control: It yield more generalibility and no recall bias. Over cross-sectional: It can look multiple outcome, rare disease, long induction and cause-effect relationship can be draw.

6) What is disadvantage of cohort study?

Answer: It is more expensive; time consuming and follow-up dropout is high.

Chapter 13- Case Control Study

1) What are the features of case-control?

Answer: It is longitudinal, observational and retrospective

2) What is the first step in case-control study?

Answer: Selecting the case then control. criteria of case: Formula [C.O.N.T.R.O.L]-Criteria fulfill, Observational only, New cases, True cases, Rare disease, Outcome uncommon, and Long induction period.

3) How do you compute for case-control study?

Answer: It can be OR only by cross multiply. (no prevalence and no incidence)

4) What does 3.1 mean in OR?

Answer: Exposure is 3.1 times more likely to get the disease compare to unexposed

5) Advantage of case-control?

Answer: Over cross sectional- Rare and long induction period of disease, multiple exposure. Cause and effect can be concluded. Over cohort: It cheaper, shorter time and less follow-up.

6) Disadvantage of case-control?

Answer: It cannot yield generalibility and are influence by recall bias.

Chapter 14- Experimental Study

1) What are the features of experimental study?

Answer: It is prospective, experimental and longitudinal

In addition: Randomization and Blinding

2)What is the first step for experimental study?

Answer: Selecting the experimental group. It is either:

-Therapeutic (disease) or prophylactic (non-disease)

-Clinical trial, community trial and field trial

-Efficiency (Internal validity), effectiveness (External Validity)

-Parallel, and cross-over

3) How do you compute?

Answer: Same with cohort: RR. and Incidence rate

In addition, treatment effect Te= (Ic-Ie)/Ic or T= 1-RR

4) What do you understand by 4.1 in Te?

Answer: There is treatment effect of 4.1 among experimental group

5) What is randomization?

Answer: It is procedure to randomly allocate. Advantage of randomization formula [C.A.S’.E]- Chances, Allocation, Semiquinone of research, Equality. Remember that random allocation NOT SAME random selection. This to address ABC.

6) What is blinding?

Answer: to prevent and address ABC: (alpha (unAcertainty), Bias, Cofounder). Classified as open label, single-blind, double-blind, triple-blind.