title: Does the precision of dual-energy X-ray absorptiometry for bone mineral density differ by sex?
abstract: Given larger bone size in men, bone mineral density (BMD) precision might differ between sexes. This study compared dual-energy X-ray absorptiometry BMD precision of 3 International Society for Clinical Densitometry-certified technologists in older men and women. Each technologist scanned a cohort of 30 men and 30 women (total n = 180) by using a Lunar iDXA densitometer (GE Healthcare, Madison, WI). Each volunteer had 2 lumbar spine and bilateral hip scans with repositioning between examinations. BMD least significant change was calculated. Age and body mass index did not differ between men and women. Mean height and weight were greater in men, 174.6 cm ± 6.9 and 81.6 kg ± 11.1 respectively, (p < 0.0001) than in women, 161.5 cm ± 5.9/69.1 kg ± 14.2, respectively. Bone area was greater in men (p < 0.0001) at all sites. BMD least significant change was statistically better (p < 0.05) in women at the mean total femur (0.014 vs 0.018 g/cm(2)) and left femoral neck (0.025 vs 0.038 g/cm(2)), but not different at either total femur, the right femoral neck, or lumbar spine (all p > 0.05). In conclusion, statistically significant male/female differences in BMD precision were observed at the mean total femur and left femoral neck. Given the small magnitude of difference in g/cm(2) and inconsistent pattern, that is, no right femoral neck difference, there is virtually no clinical difference in BMD precision between sexes. These data do not support a need for sex-specific precision analyses.
authors.affiliation: University of Wisconsin Osteoporosis Clinical Research Program, Madison, WI, USA. Electronic address: dckruege@wisc.edu.
authors.forename: Diane
authors.initials: D
authors.lastname: Krueger
authors.affiliation: University of Wisconsin Osteoporosis Clinical Research Program, Madison, WI, USA.
authors.forename: Nellie
authors.initials: N
authors.lastname: Vallarta-Ast
authors.affiliation: University of Wisconsin Osteoporosis Clinical Research Program, Madison, WI, USA.
authors.forename: Jessie
authors.initials: J
authors.lastname: Libber
authors.affiliation: Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, USA; Department of Population Health, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Gangnon
authors.affiliation: University of Wisconsin Osteoporosis Clinical Research Program, Madison, WI, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Binkley
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation*; D000368:Aged; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012737:Sex Factors
keywords: Bone density; DXA; precision; sex