Part I: Introduction to Epidemiology
- Please define epidemiology.
- Please explain how epidemiology supports public health.
- Please explain what observational research is and the main benefits and weaknesses of this strategy for conducting this type of research as compared with experimental research.
Part II: Measures of Disease Frequency
- One hundred people over 60 years of age were studied for one year in a study of high blood pressure. Twenty had high blood pressure at the start of the study and a further 10 developed high blood pressure during the period. If you assume that high blood pressure is a chronic condition; that is, once you develop it you have it for good, what is the answer to the following questions:
4a. What is the prevalence of high blood pressure at the start of the period ?
4b. What is the cumulative incidence of blood pressure?
4c. If you assume for your calculations that there were a total of 80 person years at risk in this
study, calculate the incidence rate of blood pressure in this study.?
- Please the value of prevalence as a measure of disease frequency.
- Please explain the difference between cumulative incidence and incidence. In what situation would you prefer one of these measures of disease frequency over the other.
Part III: Study Design
- Please explain your understanding of the study design hierarchy.
- Explain what is meant by an analytical study and give an example.
- You are asked to conduct an observational study investigating whether drinking tea is protective for the development of skin cancer. Please answer the following questions. What type of study would you do? Please fully explain your logic.
9b. Using brief dot points, please indicate three strengths in the approach you have taken to conduct this study and three weaknesses in this approach (
- Please read the following abstract and answer the questions that follow.
Background: Improvements in health are an important expected outcome of many housing infrastructure programs. The authors aimed to determine if improvement in the notoriously poor housing infrastructure in Australian Indigenous communities results in reduction in common childhood illness and to identify important mediating factors in this relationship.
Methods: The authors conducted a prospective cohort study of 418 children aged 7 years or younger in 10 Australian Indigenous communities, which benefited most substantially from government-funded housing programs over 2004e2005. Data on functional and hygienic state of houses, reports of common childhood illness and on socio-economic conditions were collected through inspection of household infrastructure and interviews with children's carers and householders.
Results: After adjustment for a range of potential confounding variables, the analysis showed no consistent reduction in carers' reporting of common childhood illnesses in association with improvements in household infrastructure, either for specific illnesses or for these illnesses in general. While there was strong association between improvement in household infrastructure and improvement of hygienic condition of the house, there were only marginal improvements in crowding.
Conclusions: High levels of household crowding and poor social, economic and environmental conditions in many Australian Indigenous communities appear to place major constraints on the potential for building programs to impact on the occurrence of common childhood illness. These findings reinforce the need for building programs to be supported by a range of social, behavioural and community-wide environmental interventions in order for the potential health gains of improved housing to be more fully realised.
10a) The authors indicate this is a prospective study. Why do they say this?
10b) What is the major outcome variable in this study?
10c) What are the main exposure variables indicated in the abstract?
10d) Please indicate any limitations that you may be concerned about in this study and explain your answer fully?
10e) Do you think the conclusion is supported by the evidence? Please give your opinion and include a description of the conclusion in your own words.
Part IV: Measures of Association
The following table represents the results of a cross sectional study conducted to investigate the relationship between having a vegetarian diet and having diabetes.
Please answer the following questions.
11a. Calculate the risk ratio for the association between diet and illness. Please show all of the calculations for this
11b. Interpret this and communicate findings in a sentence.
11c. Calculate the odds ratio for the association between vegetarian diet and illness
11d. Interpret this and communicate findings in a sentence.
11e. Comment on the difference between the risk ratio and the odds ratio. Are both measures valid? Which is the better measure of association to report, and why?
11f. What is the limitation of these findings that you need to highlight when you report these to someone who is not a public health practitioner.
- If your analysis of the association between eating berries and gastrointestinal disease in a restaurant outbreak gives you a risk ratio of 0.2. What is your interpretation of this?