# BASIC EPIDEMIOLOGY EXAM

QUESTION 1. As you know, epidemiology is the study of the distribution and determinants of disease frequency in humans and the application of this study to control health problems. Which types of activities do epidemiologists perform. a. Identify the etiology of a disease (e.g., causes, risk factors, preventive factors) b. Determine the extent and distribution of disease in a population c. Study the natural history or course of a disease d. Evaluate existing and new preventive and therapeutic measures, modes of health care delivery, etc e. All of the above Answer: E QUESTION 2. A group of researchers met to plan a study of causes of poor eating habits among graduate students in public health. After the meeting, the group left their building, and walked outside into a raging snowstorm. Their planning notes were ripped from their hands, and tossed to the street. Although the notes were recovered, they were hopelessly mangled and out of order. Suppose that you were the team member who offered to re-construct the notes. Which of the following steps is out of order. a. Examine existing data on the possible causes of poor eating habits data from one of the following sources: clinical practice, lab, descriptive statistics, descriptive and analytic studies. b. Design and conduct an epidemiological study to evaluate this hypothesis. c. Review the manner in which the epidemiological study was conducted. d. Formulate a specific hypothesis e. Evaluate the role of chance, bias and confounding when interpreting the study results. f. Make a judgment about the causality of the association using the “totality” of evidence. Answer: D QUESTION 3. Match the formula with the measure of disease frequency a. Prevalence b. Cumulative Incidence c. Incidence Rate 1. # of existing cases / population at a point in time 2. # of new case / population during a specified time 3. # of new case / population*time a. b. c. QUESTION 4. What are the key differences between Incidence and Prevalence? a. Incidence uses existing cases and Prevalence use new cases b. Incidence uses new cases and Prevalence uses existing cases c. Incidence is for acute illnesses only and Prevalence is for chronic illnesses only d. Incidence is for chronic diseases only and Prevalence is for acute illnesses only e. Both a and c f. Both b and d Answer: B QUESTION 5. Suppose that you are following a group of children for the development of asthma over a one- year period. You identify 100 children on January 1st, screen them for asthma, and set up a monitoring program to check on their status on a monthly basis. Five children are considered prevalent cases because they were diagnosed with asthma before January 1st. Ten children develop asthma on March 1st and another ten children develop asthma on July 1st. Another 10 children who remain healthy were followed for a total of six months and then were lost to follow-up. All of the remaining children did not develop asthma and were not lost to followup. Follow-up ended on December 31st. How many person-months of observation were accrued by this population? a. 1040 months b. 730 months c. 920 months d. 980 months Answer: C QUESTION 6. An investigation that was started on January 1 identified a population of 1,000 individuals among whom 10 were existing cases. On March 1st, 4 new cases were found. On May 1st, 4 more cases were reported. On June 1st, 10 healthy participants moved away and were lost to follow-up. Among the total of 8 new cases, there were 6 died from the disease on August 1st. The study ended on December 31, 2011. Assume that once a person got the disease, they have it for the duration of the study, and assume that all remaining participants stayed healthy and were not lost to follow-up. a. What was the prevalence of disease on Jan 1st? b. What was the prevalence on June 30th? c. c. What was the CI over the year? d. What is the incidence rate over the year? 10/1000 or 1% 18/990 or 2% 8/990 or 0.8% 818 / 100,000 person years QUESTION 7. Disease + – Exposure + a b – c d • Using the labels in the 2×2 chart, enter the correct values to the appropriate labels. • A cohort study of smoking and bladder cancer was conducted in a small island population. There were a total of 1000 people on the island. Four hundred were smokers and 600 were not. Fifty of the smokers developed bladder cancer. Ten of the non- smokers developed bladder cancer. • a = • b = • c = • d = 50 350 10 590 QUESTION 8. Calculate the RR for the above study. Enter the value as X.X to determine the correct answer. RR = 7.4 QUESTION 9. Calculate the RD for the above study. Enter the value as XX.XX% to determine the correct answer. RD = 10.80% QUESTION 10. Is the excess risk of disease among the total population generally LARGER or SMALLER than the excess risk of disease among exposed persons? a. generally larger b. generally smaller Answer: B QUESTION 11. The U. S. Census is: a. an absolute count of the U. S. population b. always the best way to obtain data for Epidemiology Research c. sometimes the best we can do, under the circumstances. • Death Certificate Data is: a. The same for every place in the country b. Standardized because only physicians can complete the form c. Should be interpreted with caution • Information obtained from a nationally sponsored survey, like BRFSS, needs no further validation. a. True b. False Answer: C,C,B QUESTION 12. Industry C Age Group Person-Years of Experience Deaths Rate per 1,000 py 20-29 25,000 30 1.2 30-39 25,000 50 2.0 40-49 25,000 75 3.0 50-59 25,000 315 12.6 20-59 100,000 470 4.7 Calculate the crude mortality rates (per 1,000 py of follow-up) for Industries A, B and C (use one digit past the decimal for your answer) Industry B Age Group Person-Years of Experience Deaths Rate per 1,000 py 20-29 10,000 20 30-39 20,000 60 40-49 30,000 150 50-59 40,000 800 20-59 100,000 1,030 Industry A Age Group Person-Years of Experience Deaths Rate per 1,000 py 20-29 40,000 80 30-39 30,000 90 40-49 20,000 100 50-59 10,000 200 20-59 100,000 470 A = 4.7 B = 10.3 C = 4.7