NR 503 Epidemiology Midterm Exam QUESTIONS AND ANSWERS

NR 503 Epidemiology Midterm Exam. NR 503 Epidemiology Midterm Exam (Latest): Chamberlain College of Nursing Question 1 The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance system that collects hospital and private physician reports of influenza cases every month. During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on April 1, 2005. The monthly incidence rate of active cases of influenza for the 3-month period was: 4 per 1,000 population 17 per 1,000 population 20 per 1,000 population 39 per 1,000 population 130 per 1,000 population Explanation: The monthly incidence rate is calculated based on the number of new cases of a disease developing during the 3-month time period. In this example, 2,200 cases of influenza developed among an average population of 36,600 persons at risk during the surveillance period. The incidence rate equals 2,200 divided by 36,600. In order to calculate the average monthly rate, the rate should then be divided by 3. Finally, the monthly rate can be multiplied by 1,000 in order to express it per the responses listed. Question 2 What would be the effect on age-specific incidence rates of uterine cancer if women with hysterectomies were excluded from the denominator of incidence calculations assuming that most women who have had hysterectomies are older than 50 years of age. The rates in all age groups would remain the same. Only rates in women older than 50 years of age would tend to decrease. Rates in women younger than 50 years would increase compared to women older than 50 years of age. Rates would increase in women older than 50 years of age but may decrease in younger women as they get older. It cannot be determined whether the rates would increase or decrease. Explanation: Women who have had hysterectomies (i.e., removal of the uterus) are no longer at risk for uterine cancer. For women older than 50 years of age, this would increase the age-specific incidence rate as there would be the same number of uterine cancers occurring among fewer women at risk. Further, rates may decrease among younger women who have had hysterectomies as they are no longer at risk for uterine cancer and thus may decrease the number of potential cases occurring in their age group over time.