Medical history, including medications Pregnancy test for females of child bearing capacity Height and weight Assessment of pubertal stage Assessment of dietary intake of calcium and vitamin D Assessment of physical activity Determination of total body bone mineral content (TBBMC), total body bone mineral density (TBBBMD), spinal BMC and BMD, and bone age radiograph Fasting morning blood draw for indices of mineral metabolism: serum calcium, phosphate, albumin, total alkaline phosphatase activity, 25(OH)D, 1,25(OH)2D, iPTH, urinary calcium and creatinine.