In: Biology
You are conducting a case control study to determine if an association exists between melanoma and indoor tanning. From a statewide cancer registry, you identify 1,107 people who were diagnosed with melanoma during the last three years. You select 1,500 controls for your study. Through a follow-up survey, you find that 696 of those with melanoma had a history of indoor tanning. 48.2% of the control group reported no exposure to indoor tanning.
Part I: Calculate the odds ratio.
Part II: Interpret your results.
First of all we will make the table-
Cases Controls
a = 696 |
b = 1500 -723 = 777 |
c = 1107 – 696 = 411 |
d = 0.482* 1500 = 723 |
Exposed to indoor tanning
Not exposed to indoor tanning
Part I: Now odds ratio = (a/c) / (b/d) = (696/411) / (777/723)
= 1.69 / 1.07 = 1.58
Part II: Since the odds ratio is greater than 1, it means that there are higher odds of melanoma happening in people exposed to indoor tanning, than in ones not exposed to indoor tanning.
Thanks!