University:
Montclair State University
Course:
MEDH 101 | Introduction to the Medical Humanities
Academic year:

2023
Views:

223

Pages:

3
Author:

SparkyNoodle

Discussion on Epidemiology II Epidemiology: The study of the distribution and determinants of health-related states or events in specific populations and the application of this study to control health problems. Epidemic: The occurrence in a community or region of a specific health-related behavior or health-related events (clearly in excess). Types of Epidemics and Their Characteristics: Common Source: Epidemic from single exposure (e.g., food poisoning). Multiple Exposure: Contaminated well (e.g., water). Propagated Epidemic: Mostly infectious from person to person. Slow Epidemic (modern): Chronic, non-communicable diseases (e.g., chronic diseases, HTN, DM). Types of Epidemiological Studies: Type of Epidemiological Study Used For Measurements Descriptive Generation of hypothesis Prevalence rate Descriptive - Cross Sectional Prevalence, assessment of validity of screening test Prevalence rate Analytic Testing hypothesis Odds ratio Analytic - Case Control Association between risk and health-related event Odds ratio Analytic - Cohort Association between risk and health-related event, incidence rate Incidence rate, Relative risk, Attributable risk Exercises: Hepatitis C Screening Test (applied to 365 persons): Sensitivity = 𝑇 𝑃 𝑇 𝑃 + 𝐹 𝑁 × 100 TP+FN TP ×100 = 80 80 + 130 × 100 = 38 % 80+130 80 ×100=38%. (Low Sensitivity) Specificity = 𝑇 𝑁 𝑇 𝑁 + 𝐹 𝑃 × 100 TN+FP TN ×100 = 150 150 + 5 × 100 = 96.1 % 150+5 150 ×100=96.1%. (High Specificity) PPV (Positive Predictive Value) = 𝑇 𝑃 𝑇 𝑃 + 𝐹 𝑃 × 100 TP+FP TP ×100 = 80 80 + 5 × 100 = 94 % 80+5 80 ×100=94%. NPV (Negative Predictive Value) = 𝑇 𝑁 𝑇 𝑁 + 𝐹 𝑁 × 100 TN+FN TN ×100 = 150 150 + 130 × 100 = 53.1 % 150+130 150 ×100=53.1%. Prevalence of Hepatitis C = 𝑇 𝑃 + 𝐹 𝑁 𝑇 𝑜 𝑡 𝑎 𝑙 × 100 Total TP+FN ×100 = 210 365 × 100 = 57.1 % 365 210 ×100=57.1%. Case-Control Study (Breast Cancer and Estrogen Therapy): By Odds Ratio = 𝑎 𝑑 𝑏 𝑐 = 2.61 bc ad =2.61. Positive association: Women exposed to estrogen therapy have 2.61 times higher risk of breast cancer. Cohort Study (Lung Cancer and Smoking): Incidence among Exposed = 𝑎 𝑎 + 𝑏 × 100 = 140 140 + 3260 × 100 = 4.12 % a+b a ×100= 140+3260 140 ×100=4.12%. Incidence among Non-Exposed = 𝑐 𝑐 + 𝑑 × 100 = 40 40 + 5960 × 100 = 0.67 % c+d c ×100= 40+5960 40 ×100=0.67%. Relative Risk (RR) = 𝐼 𝐸 𝑥 𝐼 𝑁 𝑜 𝑛 − 𝐸 𝑥 = 4.12 0.67 = 6.14 I Non−Ex I Ex = 0.67 4.12 =6.14. (Positive association) Attributable Risk (AR) = 𝐼 𝐸 𝑥 − 𝐼 𝑁 𝑜 𝑛 − 𝐸 𝑥 𝐼 𝐸 𝑥 × 100 = 4.12 − 0.67 4.12 × 100 = 83.7 % I Ex I Ex −I Non−Ex ×100= 4.12 4.12−0.67 ×100=83.7%. 83.7% of disease could be prevented by stopping smoking.