3 research outputs found
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Association of incident hip fracture with the estimated femoral strength by finite element analysis of DXA scans in the Osteoporotic Fractures in Men (MrOS) study
Finite element model can estimate bone strength better than BMD. This study used such a model to determine its association with hip fracture risk and found that the strength estimate provided limited improvement over the hip BMDs in predicting femoral neck (FN) fracture risk only.IntroductionBone fractures occur only when it is loaded beyond its ultimate strength. The goal of this study was to determine the association of femoral strength, as estimated by finite element (FE) analysis of DXA scans, with incident hip fracture as a single condition or with femoral neck (FN) and trochanter (TR) fractures separately in older men.MethodsThis prospective case-cohort study included 91 FN and 64 TR fracture cases and a random sample of 500 men (14 had a hip fracture) from the Osteoporotic Fractures in Men study during a mean ± SD follow-up of 7.7 ± 2.2 years. We analysed the baseline DXA scans of the hip using a validated plane-stress, linear-elastic FE model of the proximal femur and estimated the femoral strength during a sideways fall.ResultsThe estimated strength was significantly (P < 0.05) associated with hip fracture independent of the TR and total hip (TH) BMDs but not FN BMD, and combining the strength with BMD did not improve the hip fracture prediction. The strength estimate was associated with FN fractures independent of the FN, TR and TH BMDs; the age-BMI-BMD adjusted hazard ratio (95% CI) per SD decrease of the strength was 1.68 (1.07-2.64), 2.38 (1.57, 3.61) and 2.04 (1.34, 3.11), respectively. This association with FN fracture was as strong as FN BMD (Harrell's C index for the strength 0.81 vs. FN BMD 0.81) and stronger than TR and TH BMDs (0.8 vs. 0.78 and 0.81 vs. 0.79). The strength's association with TR fracture was not independent of hip BMD.ConclusionsAlthough the strength estimate provided additional information over the hip BMDs, its improvement in predictive ability over the hip BMDs was confined to FN fracture only and limited
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Predictors of change of trabecular bone score (TBS) in older men: results from the Osteoporotic Fractures in Men (MrOS) Study
Among older men, characteristics that predict longitudinal changes in trabecular bone score (TBS) are different from characteristics that predict changes in bone mineral density (BMD). Most notably, weight loss is strongly associated with concomitant loss in BMD but with concomitant increases in TBS, when measured on Hologic densitometers. INTRODUCTION:Our objective was to compare and contrast predictors of changes in TBS, total hip BMD, and lumbar spine BMD. METHODS:Our study population was 3969 Osteoporotic Fractures in Men (MrOS) cohort participants (mean age 72.8 years) with repeat measures of TBS, lumbar spine and total hip BMD, body mass index (BMI) less than 37 kg/m2, and no use of bisphosphonate or glucocorticoid medications. TBS was scored (Med-Imaps Software version 2.1) and BMD measured on Hologic densitometers. RESULTS:One thousand four hundred forty-four men had a TBS decrease > 0.04 units (estimated least significant change for TBS), 795 men had a TBS increase > 0.04 units, and 1730 men had TBS change ≤ 0.04 units over mean follow-up of 4.6 years. Older age was not associated with TBS change, but was associated with greater decline in lumbar spine and total hip BMD. Compared to stable weight, > 10% weight loss was strongly associated with an increase in TBS [effect size = 1.24 (95% CI 1.12, 1.36)] and strongly associated with a decrease in total hip BMD [- 1.16 (95% CI - 1.19, - 1.03)]. Other predictors discordant for longitudinal changes of TBS and BMD included baseline BMI, walk speed, and ACE inhibitor use. CONCLUSIONS:Predictors of changes in TBS are different from predictors of changes in lumbar spine and total hip BMD. At least when assessed on Hologic densitometers, weight loss is associated with subsequent declines in spine and total hip BMD but subsequent increase in TBS. Faster walk speed may protect against loss of hip BMD, but is not associated with longitudinal changes of TBS
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Associations of 25‐Hydroxyvitamin D and 1,25‐Dihydroxyvitamin D With Bone Mineral Density, Bone Mineral Density Change, and Incident Nonvertebral Fracture
Relationships between 1,25-dihydroxyvitamin D (1,25(OH)2 D) and skeletal outcomes are uncertain. We examined the associations of 1,25(OH)2 D with bone mineral density (BMD), BMD change, and incident non-vertebral fractures in a cohort of older men and compared them with those of 25-hydroxyvitamin D (25OHD). The study population included 1000 men (aged 74.6 ± 6.2 years) in the Osteoporotic Fractures in Men (MrOS) study, of which 537 men had longitudinal dual-energy X-ray absorptiometry (DXA) data (4.5 years of follow-up). A case-cohort design and Cox proportional hazards models were used to test the association between vitamin D metabolite levels and incident nonvertebral and hip fractures. Linear regression models were used to estimate the association between vitamin D measures and baseline BMD and BMD change. Interactions between 25OHD and 1,25(OH)2 D were tested for each outcome. Over an average follow-up of 5.1 years, 432 men experienced incident nonvertebral fractures, including 81 hip fractures. Higher 25OHD was associated with higher baseline BMD, slower BMD loss, and lower hip fracture risk. Conversely, men with higher 1,25(OH)2 D had lower baseline BMD. 1,25(OH)2 D was not associated with BMD loss or nonvertebral fracture. Compared with higher levels of calcitriol, the risk of hip fracture was higher in men with the lowest 1,25(OH)2 D levels (8.70 to 51.60 pg/mL) after adjustment for baseline hip BMD (hazard ratio [HR] = 1.99, 95% confidence interval [CI] 1.19-3.33). Adjustment of 1,25(OH)2 D data for 25OHD (and vice versa) had little effect on the associations observed but did attenuate the hip fracture association of both vitamin D metabolites. In older men, higher 1,25(OH)2 D was associated with lower baseline BMD but was not related to the rate of bone loss or nonvertebral fracture risk. However, with BMD adjustment, a protective association for hip fracture was found with higher 1,25(OH)2 D. The associations of 25OHD with skeletal outcomes were generally stronger than those for 1,25(OH)2 D. These results do not support the hypothesis that measures of 1,25(OH)2 D improve the ability to predict adverse skeletal outcomes when 25OHD measures are available. © 2015 American Society for Bone and Mineral Research