epi lec

• Epidemiology

  Study of factors determining disease occurrence and distribution in a population
• Epi

  means “upon”
• Demos

  means “people”
• logos

  means “study”
• Epidemiology

  data is from groups/populations, levels of population in the scientific study of disease
• Clinical Medicine

  single patient, level of individual patients in the study of disease
• Classical Epidemiology

  • Studies distribution and determinants of disease
  • Studies origins of health problems in communities, mostly infectious agents, others include nutrition, environment, behavior, economics, etc.
  • Determines risk factors to be altered to prevent/delay disease, injury, or death
• Clinical Epidemiology

  • Epidemiology applied in clinical medicine
  • Setting is in health care facilities vs community (classical)
  • Studies are done to improve management of patients
• Infectious Disease Epidemiology

  historically depended on lab

  sciences/laboratory (i.e., microbiology, serology) but now also uses statistical

  analysis
• Chronic Disease Epidemiology

  depended on complex sampling and statistical methods but now also uses molecular laboratory markers

  Some diseases are both infectious and chronic at the same time, i.e., TB, AIDS
• Natural History of Disease

  The way a disease progresses in the absence of medical or public health intervention

  Interventions may be preventive or therapeutic

  • Interventions alter the natural history of a disease in a favorable way
• Pre-disease stage

  before the disease process begin; primary preventive measures intervene to avoid exposure to agent of disease
• Latent stage

  disease process started but without symptoms; secondary prevention measures intervene to prevent/delay progression to symptomatic
• Symptomatic stage

  disease manifestation is evident; tertiary prevention measures slow, arrest, or reverse progression of disease
• Epidemiologic Triangle

  • Cause of disease are considered in terms of the HOST, AGENT, and ENVIRONMENT, plus the VECTOR
• Host

  the “who” in the epidemiologic triangle; the degree to which an individual can adapt to stressors in the environment
• Agent

  the “what” in the epidemiologic triangle; what causes the disease (biological agents, chemical, physical agents, social and psychological stressors)
• Environment

  the “where” in the epidemiologic triangle; external factors allowing for

  disease transmission; influence the probability and circumstances of contact between the host and the agent
• Vector

  transmitter of disease; has specific relationship with the agent, the

  environment, and the host
• Risk Factor and The BEINGS Model

  The BEINGS model describes the major categories of risk factors for disease

  B: biologic, behavioral factors

  E: environmental factors

  I: immunologic factors

  N: nutritional factors

  G: genetic factors à the most difficult to change

  S: [health] services, social factors, spiritual factors