When epidemiologists measure disease frequency, they analyze the incidence and prevalence of a disease. Incidence is the number of new cases of a disease in a particular population during a specific time period. This measure is useful when public health officials and epidemiologists are looking at the first occurrence of a disease. It is also important when comparing populations to determine disease risk.
For each problem, answer the following questions:
- Name the appropriate measure of disease frequency that should be used in each scenario and justify its use (why that particular measure is the appropriate one).
- The percentage of elderly men who are diagnosed with prostate cancer by age 80.
- The number of mothers who die during the first year after giving birth due to complications from the birthing process.
- On the last day of the school year, the number of freshman college students who are at least 15 pounds heavier than when they started the school year.
- Calculate the appropriate disease frequency rate. Show your work.
- The cumulative incidence rate in a population of 100,000 people where 9 new cases of disease were reported within 1 year.
- The prevalence of a chronic disease on November 1st where 9 initial cases were found in September with an additional 45 cases reported in October of a small city with a population of 75,000 people.
- The relative risk of death from exposure A if the mortality rate in the exposed group is 60 deaths per 1000 person-years and the mortality rate in the unexposed group is 20 per 1000 person-years.
The prevalence of a health condition is the existing number of cases of that condition in the population. State whether the factors listed below are likely to increase or decrease the prevalence of a health condition and Explain your reasoning.
- Improvements in diagnostic criteria
- Shorter duration of a health condition
- Decrease in the incidence of the health condition
- Loss of healthy people from the population for other reasons