Part I: For each example below indicate: (0.5 point each) Whether it is a case s
ID: 124188 • Letter: P
Question
Part I: For each example below indicate: (0.5 point each)
Whether it is a case series, ecological, or cross-sectional study;
Unit of analysis;
Whether it is possible to calculate incidence, prevalence, both, or neither;
Briefly explain your answer to c. above
Questionnaires were mailed to every 10th person listed in the city telephone directory. Each person was asked to list age, sex, smoking habits, and respiratory symptoms during the preceding seven days. About 20% of the questionnaires were completed and returned. About 10% of respondents reported having upper respiratory symptoms.
Type of study:
Unit of analysis:
Type of calculation:
Explanation:
At a major regional hospital, 200 cancer patients were interviewed and asked about smoking history, alcohol consumption, diet, and other behavioral factors.
Type of study:
Unit of analysis:
Type of calculation:
Explanation:
In a large metropolitan county in the US, data on median income for households in census tracts were obtained from the Census Bureau’s American Community Survey. Air pollution levels were measured in these same Census tracts during a period of one month. The data were analyzed using a geographic information system (GIS) to produce maps showing pollution and income levels by Census tract.
Type of study:
Unit of analysis:
Type of calculation:
Explanation:
Part II. You design a cross-sectional study to investigate smoking and peripheral vascular disease (PVD). PVD is a disease of blood vessels outside the heart, in which the extremities do not receive enough blood flow to keep up with demand. People with PVD experience symptoms such as leg pain when walking. Your data collection yields the following information:
Total respondents: 3,026
Total smokers: 1,727
Total with PVD: 31
Total nonsmokers without PVD: 1,291
Identify the exposure and health outcome. (0.5 point)
Construct a 2x2 table using the information above. Correctly label rows and columns.
(1 point)
Total
Total
What is the prevalence of the outcome within both exposures? Report in %. (0.5 point)
What is the prevalence of the exposure within both outcomes? Report in %. (0.5 point)
From your findings, is it possible to establish whether the exposure preceded the outcome? Explain your answer. (1 point)
Total
Total
Explanation / Answer
Answer: Part1
Type of study: Ecological studies
Unit of analysis: age, sex, smoking habits and respiratory symptoms on small group of population
Type of calculation: No. of cases of respiratory symptoms in the population
Explanation: Here based on small group of population data's are collected on % of people who are affected by respiratory problems and what percentage of people who are associated with smoking habits.
PartB:
Type of study: Case series
Unit of analysis: behavioural factors such as smoking and alcoholic habits
Type of calculation: Background history of 200 group of cancer patient, and trying to relate the smoking and alcoholic factors with cancer
Explanation: In this study cancer patients were interviewed and based on the data the nature of cancer and it's association with people smoking and drinking habits were corelated.
PartC:
Type of study: Ecological study
Unit of analysis: Air pollution level
Type of calculation: associated between air pollution and income levels by census tract
Explanation: For a period of one month data of pollution level were studied on median income levels by census tract.
Part D:
Total Exposure is: 1,727 and total case of PVD: 31, Health outcome: 31 case of PVD and without PVD is 1,291
a) prevalance of outcomes within both exposure : 58%
b) prevalance of exposures within both outcomes : 43.68%
c) exposure preceded the outcome around 15%. Above 1727 out of 3026 were expose to smoking among them 31 are the cases of PVD and 1291 were non-smokers who are free from PVD.