epidemiological study - cohort study Flashcards
what are the features of a cohort study ?
the groups are based selected on exposure then followed up to see who gets the disease and who doesn’t
mainly prospective
?what are they type of cohort studies ?
prospective
retrospective
reconstructive
what are the features of a retrospective cohort study ?
participants are selected after the outcome of interest has been selected and asked about their exposure
what is a reconstructive study ?
combination of both a retrospective and prospective study , also called a true cohort
what are the different measures of association that can be made from a cohort study ?
attributable risk
relative risk
incidence
what data is needed to calculate both attributable risk and relative risk ?
incidence
how is relative risk calculated ?
incidence in exposed divided by the incidence in the unexposed
how is attributable risk calculated ?
incidence in the exposed - incidence in the unexposed
what are the different conclusions that can be drawn from the relative risk ?
RR=1 disease risk is the same in exposed and unexposed
RR>1 an increased risk among exposed
RR<1 decreased risk among exposed
based on which RR value can we conclude that a factor may be protective from a disease ?
if the RR is less than 1
what are confounding factors ?
situation inn which a measure of association or effect between exposure and outcome is distorted by the presence of another variable
what is another term used to describe confounding factors ?
mixing of effects
to deal with confounding factors what are the 2 staged that intervention can be done ?
design stage
stage of analysis
what are the different approaches that can be done in the design stage to deal with confounding factors ?
restriction
randomization
matching
what are the different approaches that can be done in the analysis stage to deal with confounding factors ?
stratification modeling ( using regression models )
