03 Oct Describe the relationship between incidence and prevalence and include a concrete example?as described in Chapter 5 of?Schneider, Mary-Jane?Introduction to Public Health. Available from: Monroe Co

Chapter Objectives

After reading this chapter, students in PH 111 course should be able to:

· Define Epidemiology

· Define what is a Disease

· Define Disease Frequency

· Describe the Distribution of Disease

· Describe Determinants of Disease

· Describe the different types of Epidemiologic Studies

The above will be demonstrated by completing and submitting the assignments and by participating in the discussion(s) assigned to this chapter.

MAJOR THEMES

1. The definition of epidemiology is examined closely, analyzing important concepts upon which the science is based.

2. Formal epidemiologic studies are used to confirm or disprove hypotheses about associations between exposures and disease. The major types of epidemiologic studies are: intervention studies, cohort studies, and case control studies.

3. Epidemiologist must:

A. First define the disease in a clear way. Some diseases are easier to identify than others.

B. Measure disease frequency. That is the epidemiologist must define the disease, then count the number of cases then relate that number to the size of the population being studied to yield a rate. When calculating the rate, the denominator is the population at risk, not the entire population.

4. Types of Frequency Measures: Two types:

A. Incidence: The rate of new cases of the define population over a defined period of time.

B. Prevalence: The total number of existing cases in a defined population at a specific time.

Course Name: Introduction to Public Health I

CHAPTER 5

EPIDEMIOLOGIC PRINCIPLES AND METHODS

1

5. The distribution of disease deals with the Who, When, and Where questions:

A. Who: Characterize the disease by such factors as age, sex, race and economic status.

B. When: Looks for trends in disease frequency over time (i.e. is the frequency increasing or decreasing, etc.)

C. Where: It is crucial in tracking an outbreak.

D. Determinants of diseases: The cause or factors leading to the disease.

6. Kinds of epidemiologic studies:

A. Prospective studies: The study starts in the presence and monitors groups of people into the future, or may start from a specific point in the past and look forward from there.

B. Retrospective Studies: Look into the past for causes of diseases that people currently suffer from.

C. Intervention Studies: (i.e. chemotherapy drug). Studies done to test a new treatment for a disease.

7. Clinical Trials:

A. Control group: Not exposed to the intervention or treatment.

B. Placebo: Inactive substance similar in appearance to the drug or intervention being tested.

C. Randomized:

D. Double Blind:

IMPORTANT TERMS

disease exposure rate

population at risk incidence prevalence

distribution of disease placebo effect

randomized double-blind clinical trial intervention study

cohort study relative risk

case-control study odds ratio

FURTHER READINGS AND WEB SITES

1. Framingham Heart Study web site: www.framingham.com/heart

2. Nurses’ Health Study web site: www.channing.harvard.edu/nhs

3. Descriptions of research being conducted at the National Institutes of Health can be found on the web sites of each of the institutes. NIH web site: www.nih.gov (click on specific institute) For example, the National Cancer Institute web site has a description of epidemiologic studies conducted in the Division of Cancer Epidemiology and Genetics: http://dceg.cancer.gov