Lec 3 Final.pdf

#Epi, #Epimidiology Faculty of Medicine Epidemiology and Biostatistics (BMS222) ‫اﻟﻮﺑﺎﺋﯿﺎت واﻹﺣﺼﺎء اﻟﺤﯿﻮي‬ Lecture 1 Course Introduction...

#Epi, #Epimidiology Faculty of Medicine Epidemiology and Biostatistics (BMS222) ‫اﻟﻮﺑﺎﺋﯿﺎت واﻹﺣﺼﺎء اﻟﺤﯿﻮي‬ Lecture 1 Course Introduction Introduction to biostatistics Tariq N. Al-Shatanawi MPH PhD Record https://youtu.be/JzKvl8lUhkQ?si=p4fpVW5wdpo1fBfF 14-7-2024 1 · only observing occurrence of this disease risk factors ‫ او‬exposure ‫ما بغير اي اشي‬ persons‫ او ال‬occurrence of cases‫او ال‬ Observational studies: infected Descriptive studies Cohort (Prospective) studies Case-control (Retrospective) studies ‫ الي رح‬0‫بحدد م‬ Non-observational studies: there's intervention ‫ج الي انا‬9‫يتعرض للع‬. A 0‫عم اختبره وم‬ Experimental studies (interventional) studies Allocation for exposure.  Revision : observational answer the Answer who Analytical , 99 Determinant What, where 22 Descriptive of the disease. and When. sectional cohort study cross , Survey (snaphshot), Case control case report, case series study Non-observational. · Randomization exposure ‫ ما رح يصير عندو‬0‫ وم‬exposure ‫ رح يصير عندو‬0‫معناتو تحديد م‬ - observational : just observing things without intervention  Example of Ecologic Analysis Dependent (+) correlation Age-adjusted incidence of rectal 25 20 A ‫قصود انو‬K‫ > but latency bias could occur COHORT STUDY: ADVANTAGES ‫ مشكلتها انها عندها‬NCDs ‫ وال‬NCDs‫ئمة لل‬.‫حكينا انها م‬ ‫ ما‬q‫ مبين‬clinically‫ فممكن هدول الناس ال‬long latency period first stage of this disease ‫ يكون عندهم‬disease‫عندهم هاد ال‬ I ‫ الي انا عم بدرسه ما كان هو السبب بتشكل‬exposure‫ففعليا ال‬ ‫ كان عنده ا_رض فهيك انا بالخطأ‬.‫نو هو اص‬J ‫هاد ا_رض‬ group‫حطيتو مع ال‬ If prospective, minimizes bias in:  Selection, since enrollment is completed without knowledge of disease outcome  exposure measurement Latency Bias,  COHORT STUDIES — DISADVANTAGES 1. Follow-up: logistics, losses 2 &. Many subjects needed for rare disease e. Exposure can change over time 3 4 Prospective: time-consuming, costly, observation can influence behaviors. 5 Retrospective: requires suitable records.. Changes in practice, usage, exposures may make findings irrelevant 6 COHORT STUDY: ISSUES Is exposure unchanging throughout the period of follow-up? If persons are lost-to-follow-up, before they develop disease and before the study is completed….can they be included in the analysis? quantifying ‫ واعمل‬person time rate‫ او اضطر ادخلهم بالدراسة واطلع ال‬comulative incident‫هون رح اضطر يا اما اشيلهم واطلع ال‬ COHORT STUDY: ISSUES Was exposure accurately measured?  Were exposure data collected explicitly for the purpose of the study? Are data on potential confounders available for analysis? ‫رض‬A‫خفي الي بسبب ا‬A‫العامل ا‬ controlling ‫زم نعمللها‬N ‫بتخرب اي دراسة لذلك‬ COHORT STUDY: ISSUES Measurement of exposure status or disease outcome should be similar for all compared groups COHORT STUDIES – SUMMARY Test hypotheses about disease risk factors / causes Cohort studies Exposure  disease (cause  effect) Prospective or retrospective Measure of association = RR Often large, expensive