Week 5: Epidemiology

Scientific study of patterns, causes and effects of health and disease conditions in defined populations Can be applied to the study of a human or animal disease Cornerstone of public health Informs health policy decisions making and interventions to reduce risk from disease and to promote health

Extends the tools of epidemiology to study the effects of the environment on human health Study a wide range of health effects with potential links to environmental exposures

Main purpose is to identify and describe the distribution of health and diseases Direct information for policy and health promotion strategies Hypothesis building Surveillance

Focus is finding out the reason or cause of disease occurrence (etiology) Focus is on associations and relationships

1) Suspicion 2) Formulate hypotheses 3) Determine relationship 4) Is it causal?

The occurrence of disease or death is not a random event Most diseases or deaths have multiple determinants Outcomes can be quantitatively and/or qualitatively categorized There is an association between risk factor and outcome Causality

Inhalation Ingestion Dermal absorption or penetration Visual, aural, and psychological exposures

Habitual presence or usual occurrence of disease in a geographic area

Occurence in a community or region of a group of illnesses of similar nature, clearly in excess of normal expectancy, and derived from a common or propagated source

Epidemic that becomes widespread that affects whole regions

State or rate of disease

Rate of death

Number of new cases of a disease that occur during a specified time period in a population at risk for developing the disease

Number of affected persons present in a population at a specified time divided by the number of people in the population at that time

Consistency Biological plausibility Temporality Strength Reversibility Analogy Experimentation