Epidemiology

Epidemiology

1. Who (is affected)

   • Why (are they affected)
     • What (can be done)

2. Descriptive (who what when and where of disease)

   • Analytical (why/Hypothesis)

3. CROSS SECTION- prevelance of health outcomes at ONE point)

   • Advantages
     • Large sample size
       • Cheap
   • Disadvantages
     • by chance
       • details not remembered

4. CASE CONTROL- 1 group ill v 1 group not

   • large sample
     • based on med records
   • Advantages
   • Disadvantages
     • not even grouping
       • how in written notes? and completed?

5. COHORTS-Over time

   • Advantages
     • over time
       • Cheaper than RCTS's
   • Disadvantages
     • people leave, missing data
       • nothing else considered

6. Association is not causation

7. Chance

   • Bias (selection and measurement)
     • Counfounding

8. Bradford hill criteria

   • temporal relationship (did one thing come before the other)
     • Strength
       • plausibility
         • Consistency
           • Dose response relationship increase exposure increase risk
             • specicifity-single exposure 1 outomce
               • reversibilty remove exposure decrease risk