cross-sectional study Flashcards
cross-sectional study aka
cross-sectional
prevalence study
we measure
cross-sectional
exposure and disease measures obtained at individual level AT SAME TIME
observation
cross-sectional
single period of observation
what is cross-sectional study good for
cross-sectional
good for hypothesis generation and to estimate magnitude and distribution of a health problem
start with
cross-sectional
- defined population
- gather data on exposure and disease
- 4 groups:
- exposed, have disease
- exposed, no disease
- not exposed, have disease
- not exposed, no disease
cross-sectional calculations use
cross-sectional
prevalence
prevalence of disease in exposed formula
cross-sectional
a/a+b
prevalence of disease in non-exposed formula
cross-sectional
c/c+d
prevalence of exposure in diseased
cross-sectional
a/a+c
prevalence of exposure in not diseased
cross-sectional
b/b+d
design: finding the sample
cross-sectional
- take sample of ppl. or households in a defined geographic area
- maybe defined by study question (occupational or regional exposure)
- random sampling of an area
measuring exposure
cross-sectional
questionnaires
records
lab tests
physical measurements
what factors are easily measured by cross-sectional studies
cross-sectional
factors that don’t change as a result of disease
EX: blood group
measurement of disease
cross-sectional
questionnaire for symptoms/diagnosis
physical exam
other tests (x-ray, mammography)
if possible, determine onset
need established diagnostic criteria
confounder
cross-sectional
factor related to risk factor or exposure of interest and to health outcome (disease status)
confounders issues and how to resolve
can cause over or under estimate of observed assoication btwn exposure and health outcome
if you collect confounder data during study, you can control for it with statistics
pros
cross-sectional
based on general population, not only those seeking care
cons
cross-sectional
no incidence = no risk
can’t study disease with low prevalence
can’t determine temporality of exposure
it’s a snapshot: may not reflect exposure status when disease began
