Risk Factors for Fracture
Several clinical risk factors for fracture, including components of the FRAX fracture risk assessment tool,11 were covariates in the time-to-event analyses,including age, body-mass index (BMI, the weight in kilograms divided by the square of the height in meters), estrogen use at baseline, any fracture after 50 years of age, current smoking,current or past use of oral glucocorticoids, andself-reported rheumatoid arthritis (with a missing value classified as absence of disease).