Comparison of areal and estimated volumetric bone mineral density values between older men and women

Abstract

We compared areal bone mineral density (BMD) of the total body (TBMD), antero-posterior lumbar spine at L3 (APS), lateral spine at L3 (LS) and femoral neck (FN). In order to understand better the effect of gender-related size differences on BMD, we also compared the estimated volumetric BMD at L3 (VLS) and the femoral neck (VFN). Subjects were asymptomatic women (n = 22) and men (n = 44) with an age range of 58-79 years. BMD at each site was measured by dual-energy X-ray absorptiometry using a Hologic 2000 in array mode. Results of the statistical analyses (ANOVA) showed the men to have significantly greater BMD at all areal sites [APS, LS (p < 0.05); FN (p < 0.01); TBMD (p < 0.001)]. The two estimated volumetric comparisons, however, showed no gender differences. Results demonstrate how measures from areal BMD measures can be misleading when comparing groups of different size. In older men and women planar measures may overestimate gender differences in BMD.

Daily Physical Education in the School Curriculum in Prepubertal Girls during 1 Year is Followed by an Increase in Bone Mineral Accrual and Bone Width—Data from the Prospective Controlled Malmö Pediatric Osteoporosis Prevention Study

“…One Australian study further support this view when reporting that peak bone mass accrual and peak height velocity occur from Tanner stage II until menarche whereas the growth and bone mineral accrual are linear in Tanner stage I and the ages spanned in the current study (29). The notion that increase in bone mineral accrual in girls occur first after age 10 years and in Tanner stage II are supported in several independent cohorts of children (33)(34)(35)(36)(37)(38). Based on the consistency in this extensive literature and the fact that we followed girls at younger ages and all in Tanner stage, the study design by comparing the annual changes must be regarded as acceptable, even if there was a 1-year follow-up in the cases and a 2-year follow-up in the controls.…”

“…The controls, selected from three neighboring schools, were evaluated in November and December with the followup measurements performed during the same months but two years later. We accepted a two year follow-up in the controls, as data in the literature consistently infer that both growth and accrual of BMC and aBMD over a year and during the ages this study span, occur in a linear fashion (4,(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). The cases achieved during the study period one summer break for 9 weeks, were no intervention was given, and the controls two summer breaks.…”

Cross-Sectional Versus Longitudinal Evaluation of Bone Loss in Men and Women

“…It has become evident that much of the difference in bone density between men and women [8] and between members of different races [9±11] is due to residual confounding by skeletal size, i.e., areal BMD by DXA (in g/cm 2 ) adjusts for the area scanned but does not completely correct for the fact that wider bones are also thicker; therefore, bigger bones appear to have greater BMD even if the actual density of bone tissue is no different [1]. Rates of bone loss, as estimated from crosssectional data, also appear to be confounded by agerelated changes in bone size.…”

Gender differences in relationships between body composition components, their distribution and bone mineral density: a cross-sectional opposite sex twin study

“…Although we have only presented results based on areal BMD, we have also analysed the data as volumetric BMD, using methods previously reported [44,45], but this made no difference to the results (data not shown). It could be argued that by examining associations between multiple bone and body composition measures across two age and gender groups, some adjustment for multiple comparisons should have been applied.…”