Final answer:
The odds ratio compares the odds of exposure between diseased and non-diseased groups to understand the strength of association with a disease. Relative risk is used in cohort studies and odds ratios in case-control studies, both requiring data typically organized in a 2x2 table.
Step-by-step explanation:
The odds ratio is a measure used in epidemiological studies to determine the strength of the association between an exposure and a disease or health outcome. When calculating the odds ratio, one compares the odds of exposure among those with the disease to the odds of exposure among those without the disease. The odds of exposure are calculated by dividing the number of exposed individuals by the number of non-exposed individuals within each group (diseased and non-diseased).
Relative risk, on the other hand, is determined by dividing the incidence of a health event among the exposed group by the incidence in the unexposed group. Importantly, relative risk is a concept that is typically used in cohort studies, whereas odds ratios are more commonly used in case-control studies. To accurately calculate these measures, epidemiologists often use a 2x2 table to organize the data. The final answer would indicate whether there is an increased, decreased, or no change in risk associated with the exposure. For example, a relative risk of more than one implies an increased risk from the exposure, just as an odds ratio greater than one would. Practically speaking, this could be critical in determining the cause of sporadic outbreaks or evaluating the impact of a risk factor like smoking on health outcomes like cardiovascular disease.