14. History and objectives of epidemiology

• Epidemiology is the study of determinants and distribution of disease
• Clinical epidemiology is the use of epidemiology to improve prevention, detection, and treatment of disease
• History of epidemiology
  • Hippocrates: “Quality of water, how people live, what they drink and eat, whether they exercise, affect their health”
  • Ignaz Semmelweis discovered that hand disinfection reduced the incidence of puerperal fever
  • John Snow
    • The father of epidemiology
    • Challenged the “miasma theory”, which described that disease occurs due to “miasma”, an airborne poison from unsanitary conditions
    • Snow’s hypothesis was that a part of London had increased incidence of cholera due to that part of London receiving water from a polluted part of the river Thames
    • He also traced a cholera outbreak to a single water pump which was contaminated by a young cholera patient
  • James Lind: divided sailors with scurvy into groups, and gave citrus fruits to some of them
  • Sir Percival Pott:
    • Recognized the association between scrotal cancer and chimney sweeping
  • Katsusaburou Yamagiwa: Confirmed that coal tar could induce cancer by inducing cancer in rabbit ears
  • Eradication of smallpox in 1978
  • Identification of AIDS, prediction that it was due to a sexually transmitted virus and development of preventative measures before the HIV virus itself was identified
  • Infants who lie on their stomach have much higher risk of SIDS
• Objectives of epidemiology
  • Description of diseases occurrences and patterns
  • Identification of causative agents and risk factors
  • Application of results at the population level