Epiemiology

EPIDEMIOLOGY

epidemiology=study of distibution+determinants of health related states/events - specified population+application of study - control of health problems

• clinical medicine - emphasis on individual 
• epidemiology - examination, patterns of disease - groups individuals
• highly quantitative discipline - principles, statistics+research methodologies

• epidemiology - populations
  • gender, age, genetic background, social background, level of education, use of drugs, geographical location, dietary patterns, lifestyle

• john snow, 1854 - cholera outbreak london

• epidemiology today
  • directed at chronic diseases - cardiovascular disease, cancer, diabetes, dementias
  • identifying + quantifying health risks - cigarette smoking, asbestos, radiation

• aims- epidemiological studies
  • determine distribution - disease
  • examine determinants - disease
  • judge whether given exposure causes/prevents disease

• objectives - epidemiology
  • identify causes - disease+factors increase risk
  • describe extent disease found - community
  • describe natural history+characteristics - disease
  • evaluate preventive/therapeutic measures
  • guide policy decisions

• basis - epidemiology
  • disease, illness+ill health - not randomly distributed - population

• epidemiology - used?
  • analytical tool - studying diseases - determinants
  • steer public health decision making+aids developing+evaluating interventions - control+prevent health problems

• what happened
• who was affected
• where were they affected
• when were they affected
• how were they affected
• why did it happen

• determinants - disease
  • host/agent/environment

• agent - necessary ingredient - production disease
  • infectious? virus, bacteria, waterborne/airborne
  • non infectious? chemical exposure, radiation

• environmental factors - likelihood of disease occurrence
  • population density
  • geography 
  • weather/season

• host
  • biological+behavioural qualities - individual
  • factors influence exposure - disease causing agents+occurrence disease after exposure

epidemic=occurrence of disease - clearly excess numbers of cases normally found/expected - confined limited population=outbreak

endemic=constant low level presence - disease/infection. defined geographic location

• basic measures - disease frequency
  • attack rate 
  • incidence
  • prevalence

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