1. A 34-year-old asthmatic male presents for a check-up. He has been taking low dose oral prednisone for over 10 years and although his asthma is well controlled, he is concerned about steroid-induced osteoporosis, because his grandfather, a type 1 diabetic, recently fell and broke his hip. A comprehensive metabolic profile as well as a dual energy x-ray absorptiometry test (DEXA) of the spine and hip are ordered. Which of the following additional tests would be recommended?