Bone densitometry

Bone mineral density (BMD) in the spine (L1-L4) and the total body were calculated using the dual energy X-ray absorptiometry method (DXA) (QDR HOLOGIC - 4500, 26th version 8: 3; Bedford, MA, USA). A z-score below two standard deviations for what was expected according to chronological age of the patient was defined as low BMD, as defined by the official consensus of Brazilian Society of Clinical Densitometry in 2006 (Zerbini et al., 2007). DXA was performed preferentially once a year for each patient; however, some cases did not follow this recommendation due to local limitation.