Name the appropriate measure of disease frequency that should be used in each scenario below and justify its use

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).
  
  1. The percentage of elderly men who are diagnosed with prostate cancer by age 80.
  2. The number of mothers who die during the first year after giving birth due to complications from the birthing process.
  3. 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.
  
  1. The cumulative incidence rate in a population of 100,000 people where 9 new cases of disease were reported within 1 year.
  2. 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.
  3. 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.

1. Improvements in diagnostic criteria
2. Shorter duration of a health condition
3. Decrease in the incidence of the health condition
4. Loss of healthy people from the population for other reasons