A history of dietary supplement with calcium was recorded among 10,000 women over the age of 50. The women were followed for 2 years to determine if they experienced hip fracture. Calcium supplementation was reported by 31% of women who experienced hip fracture and by 46% of all the other women. What is the measure of association between calcium supplementation and hip fracture? a. Odds ratio = 0.53
b. Relative risk = 0.72
c. Relative risk = 1.39
d. Odds ratio = 1.89

Explain the meaning of the measure of association you calculated.