MOH COMPRE EXAM REVIEW

DESCRIPTIVE EPIDEMIOLOGY Describe and summarize disease pattern (person, place and time) to generate hypothesis. Does not use comparison groups.   Uses of Descriptive Study Epidemiologists - Identification of factors that possible contribute to (or inhibit) disease development that can be reduced/eliminated/altered/prevented   Public Health Administrators - Knowledge of the burden of the disease (i.e., which population or subpopulations are affected) that is necessary for evidenced based decision in fund allocation for planning   Sources of Data for Descriptive Studies - Census, vital records, surveys, patient records from hospitals and clinics, employment health records   Classification of Descriptive Study Designs according to type of data collected -individual (case report/series and prevalence survey) -aggregate/group (ecological)   TYPES OF DESCRIPTIVE STUDY DESIGN Case Report - A study of one diseased individual. Typically, an uncommon disease or set of sympotms. The study design would not require a comparison.   Case Series - A study of multiple occurrences of unusual cases that have similar characteristics. Investigators can calculate the frequency of symptoms or characteristics among the cases.   Prevalence Survey - A study that determines the proportion of individuals with disease (or rather health event) in a defined population at a given time point. Provides "snapshot" of the population's health experience at a specified time.   Ecologic Study - A study in which at least one variable, either an exposure or the outcome, is measured at the group (not individual) level.     ANALYTIC EPIDEMIOLOGY The hallmark feature of an analytic epidemiologic study: Use of an appropriate comparison group to estimate counterfactual scenario   Observational vs Experimental - absence or presence of manipulation of the exposure variable Cross-sectional vs Longitudinal - exposure and outcome relate to one or two time points in the life of the subject Retrospective vs Prospective - direction of inquiry on the presence of exposure and outcome (E to O/O to E)   OBSERVATIONAL Cross-sectional -a study in which a sample of persons from a population are enrolled and their exposures and health outcomes are measured simultaneously -It is more useful for descriptive epidemiology than it is for analytic epidemiology -It is synonymous with survey Advantage usually representative samples used; less expensive and time consuming key feature of a cross-sectional study: It usually provides information on prevalence rather than incidence EXAMPLE Representative sample of residents were telephoned and asked how much they exercise each week and whether they currently have (have ever been diagnosed with) heart disease   Case-control -An observational analytic study that identifies individuals who develop the disease (cases) and individuals without the disease (controls), and then determines the previous exposure for each case and control. -The case group is composed only of individuals known to have the disease or outcome; the control group is drawn from a comparable population who do NOT have the disease or outcome. -We then compare the odds of exposure between cases and controls. The measure of association for a case-control study is typically an odds ratio. -A case-control study is stronger than a cross-sectional study in establishing individual-level causality because we are more certain that exposure preceded the disease outcome.   EXAMPLE Persons diagnosed with new-onset Lyme disease were asked how often they walk through woods, use insect repellant, wear short sleeves and pants, etc. Twice as many patients without Lyme disease from the same physician's practice were asked the same questions, and the responses in the two groups were compared.   British investigators conducted a study to compare measles-mumps-rubella (MMR) vaccine history among 1,294 children with pervasive...

Workplace Safety concepts and principles

occupational health and safety workplace safety industrial safety workplace hazards