Case Control Study Odds Ratio Interpretation
Or those in a traffic accident were 62% more likely to have been texting while driving.
Now I'd like you to create a two by two table and calculate the odds ratio for this example and interpret your results, and then check back in a minute. 218 cases of paralytic shellfish poisoning and 45 controls who consumed scallops. There are other permutations, but here's a short one.Rural areas with little access to regular health care. A total of 25 cases and 19 controls were identified.Data obtained from the cases and controls found that 15 cases and 12 controls had received the vaccine.Mathematically, this is the same as the cross product, which is equal to a times d divided by b times c.The odds ratio is the ratio of the odds of the health outcome or disease in the exposed Relative to the odds of the disease or health outcome in the none exposed or less exposed group.And then we see there were 22 cases in 89 controls who did not consume scallops. Cases were 19.6 times as likely, compared to controls to have eaten the scallops.So to calculate the odds ration, you take the cross product, which is 218 times 89, divided by 45 times 22. But the most precise interpretation is as follows the odds of a traffic accident among those who texted while driving was 1.62 times the odds of a traffic accident. Be careful, you cannot calculate a risk or rate directly from case control data.The denominators obtained in a case control study do not represent the total number of exposed and non-exposed person in the source population.Lets look at an example of calculating and interpreting the odds ratio, using childhood vaccines and human papillomavirus.Researchers conducted a case control study to examine whether childhood vaccines Protected children against HPV in real world conditions i.e.