Karteikarten
Longitudinal Studies
Karten in diesem Stapel (50)
- 1What is a longitudinal study?A study in which measurements of risk/outcomes are assessed repeatedly over time
- 2Longitudinal study - repeated cross sections are the only one type that:Different groups of people at different time point from the same population
- 3The majority of longitudinal studies such as panel cohort etc. examinethe same individuals over time
- 4What is a cohort?a group of individuals who share a common circumstance or significant life event
- 5Types of cohortsmany kinds, birth control, employment cohorts
- 6Individuals vary inlevel of exposure to risk factor of interest
- 7What are the two types of cohort studies:Prospective and Retrospective
- 8What is a prospective cohort study used for?For assessing risk factors, disease free subjects are followed from the baseline survey (1st survey)
- 9What happens in a retrospective cohrot studyThe investigator goes back into history to define a risk group and follows the group members up to the present to observe outcome
- 10What are the advantages of a Retrospective cohort studyCan be less expensive than the prospective studies and can focus on a group of individuals with a specific past exposure
- 11What are 2 disadvantages of retrospective cohort study1. Cannot accurately assess and validate exposure 2. Exposure was not measures or intended for research purposes
- 12Case controls:Dont know they come ffrom the same cohort and they rely on recal
- 13Retro. Cohorts:Know they come from cohort and have data from past
- 14Both retro and Case controls areCheap
- 15What is an open cohort studyEligible subjects may enter/leave the study at any given time: Variability in the follow up period( at risk)
- 16CLoased Cohort Study is1. No one can be added once follow up begins 2. Not common in practice; but there are some examples: food borne outbreaks, A bomb survivers,
- 17What is a gernal population group:defined by person, place or time: Murses Health study , defined by place such as Framinghan Heart Study
- 18A general cohort is used whenthe study exposure is fairly common: high blood preasure
- 19The comparison group ( non exposed) is part ofthe general cohort; an internal comparison group
- 20A specisl exposure cohort is typically used when the study exposure isuncomman or unique
- 21Special Exposure cohort exemplifiesthe utility of investigating rare exposures
- 22A Special Exposure Cohort usually requires anexternal comparison group
- 23The external comparison group is similar as possible tothe special exposure group except for study exposure
- 24General population is frequentlychosesen as external comparison groups fro occupational cohort studies.
- 25The Healthy Workers Effectcan underestimate a true association
- 26In a general cohort you starte withDefined population: then not randomly assighn exposed and non exposed ( follow them up), then that gets dividded into diseas and non disease
- 27In a special exposure cohort you start withExposed and not exposed then follow up for disease and no disease in each
- 28It is critical to determineExposure status prior to follow up: also need to collect relevant baseline data (demographics)
- 29Prospective Cohort studie mthods includeinterviews, medical reccord , physical exams . biological specimes, etc
- 30Retrospective Cohort studies:employment company medical records, may by only means of classifying exposure
- 31Retreospective cohort stuides tend to besecondary data sources not intended for research
- 32When determining outcome status it is critical thatthe methods be applied equally to exposed and non exposed subjects
- 33When determining outcome stuus in prospective cohort studies you can use:medical records, death certificates, questionarrs/interviews, physical exams and diagnostic tests. Also, make every effort to avoid "diagnostic suspicion bias/surveillance bias"
- 34When determining outcome studies of Retrospective cohort studies:1. Locating subjects can be particularly problematic 2. Can utilize death certificates, population - based disease registries.
- 35Following up study participants is imperative:to maintain regular contact with participants in a prospective cohort study
- 36Lost to follow - up bias is characterized by thefollow up sample which differs from the original study population with regard to exposure and outcome
- 37A gernal rule of thumb for the lost to follow up bias is:losses should be no more than 20 %
- 38Efforst to avoid lost to follow up includemaintaining up to date contact information including relatives, providing an incentive or participation ( dollas)
- 39Individual matching in cohort studies can bean effective means of controlling for confounding, yet it is rarely preformed
- 40Idividual matching is raley preformed becuase:Multiple outcomes often examined; thus,it is unclear what factors are likley to be potential confounders
- 41What are 3 advantages of prospective cohort study:1. Provides incidence and relative risk of disease 2. Can establish temporal relationship 3. Ideal for studying natural histroy disease( developmental stages)
- 42What are 3 advantages of prospective cohort study:4. Can study rare exposure(select cohort with known exposures) 5. Can examine multiple outcomes in relation to single risk factor 6. Avoids many basis (recall) associated with case control
- 43What are some limitations of Prospective cohort study1. Very expensive and lengthy 2. Not ideal for rare diseases 3. Change over time in criteria and method 4. Can only study risk factors measure at start of study 5. High attrition can affect validity of the findings
- 44Attrition meansa term used to describe the loss of subjects over the period of longitudinal study " lost to follow up"
- 45Limitation of prospective cohort studies:1. Can only study risk factors measure at the start of study 2. High attrition can affect validity of the findings
- 46What is the background of 50 yr cohort study of British physiciansCase control studies in 1950 (US and Europe) indicated a strong association between smoking and lung cancer:
- 47THe need for a stud deighn that wasless prone to bias
- 48a propective study of male British phycisanswas intiated
- 49What was the rationale for using physicianssmoking habits may be recorded with more accuracy, Subsequent mortality could be easily identified because of a medical register of licensed physicians
- 50The results deomstrated:differences in mortality by smoking status over time among the British physicians
Informationen
- Beschreibung
- college Epid (Cross Sectional Study) Karteikarten am Longitudinal Studies, erstellt von maxytrejo1 am 21/05/2014.
- Erstellt von
- maxytrejo1
- Aufrufe
- 33
- Bewertung