CH3 Epidemiology and Toxicology Flashcards
difference between analytical and descriptive epidemiology
descriptive- who what where when; makes comparisons and develops hypotheses based on observed distributions
analytical- tests hypotheses from descriptive studies(and then makes comparisons)
what is clustering
closely grouped series of events or cases of a disease (spatial- geographic or temporal- time intervals)
usually extremely unusual event
why we use occupational epidemiology studies to apply to general population
exposure to hazards occurs at higher frequency in workers, also most of population is employed
difference between counts and ratios and proportions
counts= number of disease cases ratios= fraction proportions= a ratio in which numerator is part of denominator (prevalence)
what is prevelance (also point and period prevalence)
# of people affected/ # in population point= proportion of cases at a point in time period= proportion during time period (week, month,etc)
define incidence
number of instances during a period of time (# of new cases/ total population at risk)
limitations of crude rates for comparing populations
can be affected by systemic factors (age, demographic, etc.), may not reflect true variations in rates.
use specific rates instead
when do we use the indirect method of rate adjustment
when standard population and age-specific rates are not readily available (often used for occupational studies)
3 compontents of eidemiological triangle
agent, environment, host
occupational health data sources
surveillance data, surveys, exposure measurements, employment records, statistics data
gold standard for evidence-based practice
clinical trials
what are cross-sectional studies
investigate relationship between diseases and other variables of interest in a population at one time
what are ecological studies
units of analysis are populations or groups, rather than individuals (ex different occupational groups)
what is a case-control study
participants based on presence or absence of outcome or disease of interest (case and control groups)
evaluate many diff exposures but few outcomes
retrospective
what an odds ratio measures
association between exposure and outcome in case-control study
what is a cohort study
subjects classified w exposure and observes them overtime to document new disease cases
evaluates many diff outcomes, few exposures
what is relative risk (cohort study)
measure of association, ratio of disease incident rates in exposed to incident rates of nonexposed
what is an experimental study
factor is manipulated (such as an exposure)
what is a confounding variable
other factors that may influence occurence of the outcome (ex: silica exposed workers may have higher smoking rates)
what is the threshold of the dose-response curvre
lowest dose at which a particular response may occur
john snow’s epidemiologic study in london looked at
cholera outbreak in soho district, mapped well locations, is now regarded as father of epidemiology
Which of the following observational designs is used for hypothesis testing?
cross sectional or ecologic
list all 3 workplace exposure limit abbreviations
OEL (occupational expsoure limit)
TLV (threshhold limit value)
BEIs (biological exposure indices
what is a pandemic
Occurrence of illness worldwide or crossing international bounds of large numbers
