NR 503 Epidemiology Final Exam Review

NR 503 Epidemiology Final Exam Review 1. Which of the following are examples of a population prevalence rate? A. The number of ear infections suffered by 3-year-old children in March, 2006 B. The number of persons with hypertension per 100,000 population C. The number of cases of skin cancer diagnosed in a dermatology clinic D. B & C - B. The number of persons with hypertension per 100,000 population 2. Which of the following is an advantage of active surveillance? A. Requires less project staff B. Is relatively inexpensive to employ C. More accurate due to reduced reporting burden for health care providers D. Relies on different disease definitions to account for all cases - C. More accurate due to reduced reporting burden for health care providers 3. 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: E. 130 per 1,000 population A. 4 per 1,000 population B. 17 per 1,000 population C. 20 per 1,000 population D. 39 per 1,000 population - C. 20 per 1,000 population 4. 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 prevalence rate of active influenza as of April 1, 2005, was: A. 10 per 1,000 population B. 14 per 1,000 population C. 17.5 per 1,000 population D. 20 per 1,000 population - D. 20 per 1,000 population 5. The prevalence rate as of April 1, 2005, is equal to the number of active influenza cases reported divided by the number of persons at risk in the population at that time. The best estimate of the population size is that from the February 15 count, less who are no longer at risk as they have already recovered from influenza and have developed immunity. Therefore, prevalence equals 705 cases divided by 36,600 less 1,495 recovered cases. This number can be multiplied by 1,000 in order to estimate a prevalence rate of 20 cases per 1,000 persons. 6. 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. What can be inferred about influenza cases occurring in the city? A. Active surveillance would enable better prevention of influenza B. The incidence rate would decrease if active surveillance were employed C. The average duration of influenza is approximately 1 month D. The actual number of influenza cases occurring in the population is less since hospitals and private physicians may be reporting the same patients. - C. The average duration of influenza is approximately 1 month Since the average monthly incidence rate is 20 per 1,000 and the prevalence rate is also 20 per 1,000, then the duration of disease must equal 1 month. 7. A study found that adults older than age 50 had a higher prevalence of pneumonia than those who were younger than age 50. Which of the following is consistent with this finding? A. Younger adults have a higher incidence of pneumonia B. Older adults have a higher case-fatality rate from pneumonia C. Younger adults with pneumonia are more likely to report being ill than older persons D. Incidence rates do not vary by age, but older adults have pneumonia for a longer duration compared to younger adults - D. Incidence rates do not vary by age, but older adults have pneumonia for a longer duration compared to younger adults For prevalence to be higher among older adults, either incidence or duration of pneumonia must be increased in this age group. For prevalence to be higher among older adults, either incidence or duration of pneumonia must be increased in this age group. 8. For a disease such as liver cancer, which is highly fatal and of short duration, which of the following statements is true? Choose the best answer. A. Mortality rates will be much higher than incidence rates B. Mortality rates will be much higher than prevalence rates C. Incidence rates will be much higher than mortality rates D. Incidence rates will be equal to mortality rates - D. Incidence rates will be equal to mortality rates Since the 5-year survival rate for liver cancer is 4%, most incident cases of liver cancer will result in a premature mortality. In this case, the mortality and incidence rates will be approximately equal. 9. Which of the following is a measure of disease prognosis? A. Prevalence B. Median survival time C. Age-adjusted mortality rates D. Standardized mortality ratio - B. Median survival time 10. Which of the following may be a factor that would result from the inability to use randomization in a cohort study? A. The possibility that a factor which leads to exposure may be causally associated with the disease B. The possibility that a higher proportion of exposed persons may be included in the study C. The possibility that a higher proportion of nonexposed persons may be included in the study D. The study will take longer to conduct if randomization is not used - A. The possibility that a factor which leads to exposure may be causally associated with the disease Randomization removes potential bias from the designation of treatment, or exposure, groups. Without this step, it may be likely that the exposed and nonexposed groups in a cohort study are misidentified due to other factors that are associated with exposure and subsequent disease outcomes.