Epidemiology final exam| 112 questions| with complete solutions

It measures the assocation between an exposure and an outcome. correct answer: Odds ratio What does the likelihood ratio measure? correct answer: The performance of a diagnostic test. It expresses the ratio of 2 probabilities. Probability of a given test result in a person with a disease/probability of the same result in a person without the disease. It expresses how many more or less times likely a test result is found in a person with a disease compared with a person without a disease. Incorporates sensitivity and specificity into one number. Not affected by prevalence. correct answer: Likelihood ratio Probability of a positive result in a person with a disease/probability of a positive result in a person without the disease. correct answer: Positive likelihood ratio (LR+) Probability of a negative result in a person with a disease/probability of a negative result in a person without the disease. correct answer: Negative likelihood ratio (LR-) What does LR 1 indicate? Less than 1? Equal to 1? correct answer: Greater than 1 - presence of disease Less than 1 - absence of disease Equal to 1 - the test has no diagnostic value Chronic autoimmune disease characterized by weaknesses of skeletal muscles. Antibodies block, alter, or destroy receptors for ACH neuromuscular junction. Difficulty breathing, swallowing. 90% develop ocular signs and symptoms. correct answer: Myasthenia gravis What are some advantages of likelihood ratios? correct answer: Reflect not just normal vs abnormal, but degree of abnormality of the test result. Extremely high or low test results weighted more. Can improve diagnostic ability by combining LRs of multiple tests. Much of what we know about risk factors for cardiovascular disease come from what study? correct answer: Framingham heart study - prospective cohort study A prospective cohort study of heath status and health-related quality of life. Examined prevalence and incidence of AMD, cataract, and diabetic retinopathy, glaucoma and other eye diseases. Found link between modifiable risk factors and disease. Cigarette smoking and both cataract and AMD. Lutein intake and lower risk of cataract. Systems developed to photograph cataracts and AMD, including a standardized scale. correct answer: Beaver Dam health outcomes study What did the Framingham study find out about dementia? correct answer: Prevalence is increasing due to longer living, incidence was found to have decreased. Decrease in incidence of dementia was only seen in individuals with at least a high school diploma. Beaver Dam study found a connection betwe