Robin Bell; Week 1 MED1022; Population Health
Epidemiology studies the determinants and distribution of health related states or events in populations. It primarily looks at social determinants of health. A risk factor is sufficient if it is enough to cause disease. It is necessary if it is required to cause disease. Most disease is multifactorial. Risk factors can be predisposing such as age or sex; enabling or disabling such as low income or poor nutrition, precipitating such as exposure to a disease agent or reinforcing as in repeated exposure.
For evidence to imply causation there must be a temporal relationship, it must be plausible by being consistent with other knowledge, consistent, strong, responsive according to dose and hopefully reversible. Factors resulting in a non-causal association are confounding, selection/measurement bias and chance. T tests and chi squared tests are used to determine the probability that the results lie within the range and support the hypothesis.