Effects of a Randomized Weight Loss Intervention Trial in Obese Adolescents on Tibia and Radius Bone Geometry and Volumetric Density

Obese adolescents have increased fracture risk, but effects of alterations in adiposity on bone accrual and strength in obese adolescents are not understood. We evaluated 12-month changes in trabecular and cortical volumetric bone mineral density (vBMD) and cortical geometry in obese adolescents undergoing a randomized weight management program, and investigated the effect of body composition changes on bone outcomes. Peripheral quantitative computed tomography (pQCT) of the radius and tibia, and whole-body dual-energy X-ray absorptiometry (DXA) scans were obtained at baseline, 6 months, and 12 months in 91 obese adolescents randomized to standard care versus behavioral intervention for weight loss. Longitudinal models assessed effects of body composition changes on bone outcomes, adjusted for age, bone length, and African-American ancestry, and stratified by sex. Secondary analyses included adjustment for physical activity, maturation, vitamin D, and inflammatory biomarkers. Baseline body mass index (BMI) was similar between intervention groups. Twelve-month change in BMI in the standard care group was 1.0 kg/m² versus -0.4 kg/m² in the behavioral intervention group (p < 0.01). Intervention groups were similar in bone outcomes, so they were combined for subsequent analyses. For the tibia, BMI change was not associated with change in vBMD or structure. Greater baseline lean body mass index (LBMI) associated with higher cortical vBMD in males, trabecular vBMD in females, and polar section modulus (pZ) and periosteal circumference (Peri-C) in both sexes. In females, change in LBMI positively associated with gains in pZ and Peri-C. Baseline visceral adipose tissue (VFAT) was inversely associated with pZ in males and cortical vBMD in females. Change in VFAT did not affect bone outcomes. For the radius, BMI and LBMI changes positively associated with pZ in males. Thus, in obese adolescents, weight loss intervention with modest changes in BMI was not detrimental to radius or tibia bone strength, and changes in lean, but not adiposity, measures were beneficial to bone development. © 2017 American Society for Bone and Mineral Research.

Longitudinal FGF23 Trajectories and Mortality in Patients with CKD

Elevated fibroblast growth factor 23 (FGF23) levels, measured at a single time, are strongly associated with increased risk of mortality in patients with CKD. There are minimal data on serial FGF23 measurements in CKD. In a prospective case-cohort study of the Chronic Renal Insufficiency Cohort, we measured FGF23 at two to five annual time points (mean 4.0±1.2) in a randomly selected subcohort of 1135 participants, of whom 203 died, and all remaining 390 participants who died through mid-2013. Higher FGF23 was independently associated with increased risk of death in multivariable-adjusted analyses of time-varying FGF23 (hazard ratio per 1-SD increase in ln-transformed FGF23, 1.84; 95% CI, 1.67 to 2.03). Median FGF23 was stable over 5 years of follow-up, but its gradually right-skewed distribution suggested a subpopulation with markedly elevated FGF23. Trajectory analysis revealed three distinct trajectories: stable FGF23 in the majority of participants (slope of lnFGF23 per year =0.03, 95% CI, 0.02 to 0.04, n=724) and smaller subpopulations with slowly (slope=0.14, 95% CI, 0.12 to 0.16, n=486) or rapidly (slope=0.46, 95% CI, 0.38 to 0.54, n=99) rising levels. Compared with stable FGF23, participants with slowly rising FGF23 trajectories were at 4.49-fold higher risk of death (95% CI, 3.17 to 6.35) and individuals with rapidly rising FGF23 trajectories were at 15.23-fold higher risk of death (95% CI, 8.24 to 28.14) in fully adjusted analyses. Trajectory analyses that used four or three annual FGF23 measurements yielded qualitatively similar results. In conclusion, FGF23 levels are stable over time in the majority of patients with CKD, but serial measurements identify subpopulations with rising levels and exceptionally high risk of death.

Declining Rates of Hip Fracture in End-Stage Renal Disease: Analysis From the 2003-2011 Nationwide Inpatient Sample

The incidence of hip fracture in patients with end-stage renal disease (ESRD) is considerably higher than that in the general age- and sex-matched population. Although medical therapy for chronic kidney disease mineral bone disorder (CKD-MBD) has changed considerably over the last decade, rates of hip fracture in the entire ESRD population have not been well-characterized. Herein, we evaluated temporal trends in rates of hip fracture, in-hospital mortality, and costs of associated hospital stay in ESRD. We identified hospitalizations for hip fracture from 2003 to 2011 using the Nationwide Inpatient Sample, a representative national database inclusive of all ages and payers. We incorporated data from the United States Renal Data System and the US Census to calculate population-specific rates. Between 2003 and 2011, we identified 47,510 hip fractures in the ESRD population. The overall rate of hip fracture was 10.04/1000 person-years. The rate was 3.73/1000 person-years in patients aged less than 65 years, and 20.97/1000 person-years in patients aged 65 or older. Age- and sex-standardized rates decreased by 12.6% from 2003 (10.23/1000 person-years; 95% confidence interval [CI], 7.99/1000 to 12.47/1000) to 2011 (8.94/1000 person-years; 95% CI, 7.12/1000 to 10.75/1000). Hip fracture rates over time were virtually identical in patients aged less than 65 years; however, rates decreased by 15.3% among patients aged 65 years or older; rates declined more rapidly in older women compared with older men (p for interaction = 0.047). In-hospital mortality rate after hip fracture operation declined by 26.7% from 2003 (8.6%; 95% CI, 6.8 to 10.4) to 2011 (6.3%; 95% CI, 4.9 to 7.7). In ESRD, age- and sex-standardized hip fracture rates and associated in-hospital mortality have declined substantially over the last decade. © 2017 American Society for Bone and Mineral Research.

Musculoskeletal health in newly diagnosed children with Crohn's disease

We evaluated the impact of Crohn's disease on muscle and bone strength, mass, density, and geometry in children with newly diagnosed CD and found profound muscle and bone deficits; nevertheless, the prevalence of vertebral fractures at this time point was low.

INTRODUCTION

Crohn's disease (CD) is an inflammatory condition of the gastrointestinal tract that can affect the musculoskeletal system. The objective of this study was to determine the prevalence of vertebral fractures and the impact of CD on muscle and bone mass, strength, density, and geometry in children with newly diagnosed CD.

METHODS

Seventy-three children (26 girls) aged 7.0 to 17.7 years were examined within 35 days following CD diagnosis by lateral spine radiograph for vertebral fractures and by jumping mechanography for muscle strength. Bone and muscle mass, density, and geometry were assessed by dual-energy x-ray absorptiometry and peripheral quantitative computed tomography (pQCT).

RESULTS

Disease activity was moderate to severe in 66 (90%) patients. Mean height (Z-score -0.3, standard deviation (SD) 1.1, p = 0.02), weight (Z-score -0.8, SD 1.3, p < 0.01), body mass index (Z-score -1.0, SD 1.3, p < 0.01), lumbar spine areal bone mineral density (BMD; Z-score -1.1, SD 1.0, p < 0.01), total body bone mineral content (Z-score -1.5, SD 1.0, p < 0.01), and total body lean mass (Z-score -2.5, SD 1.1, p < 0.01) were all low for age and gender. pQCT showed reduced trabecular volumetric BMD at the tibial metaphysis, expansion of the bone marrow cavity and thin cortices at the diaphysis, and low calf muscle cross-sectional area. Jumping mechanography demonstrated low muscle power. Only one patient had a vertebral fracture.

CONCLUSIONS

Children with newly diagnosed CD have profound muscle and bone deficits; nevertheless, the prevalence of vertebral fractures at this time point was low.

The Efficacy of Low-intensity Vibration to Improve Bone Health in Patients with End-stage Renal Disease Is Highly Dependent on Compliance and Muscle Response

RATIONAL AND OBJECTIVES

Low intensity vibration (LIV) may represent a nondrug strategy to mitigate bone deficits in patients with end-stage renal disease.

MATERIALS AND METHODS

Thirty end-stage renal patients on maintenance hemodialysis were randomized to stand for 20 minutes each day on either an active or placebo LIV device. Analysis at baseline and completion of 6-month intervention included magnetic resonance imaging (tibia and fibula stiffness; trabecular thickness, number, separation, bone volume fraction, plate-to-rod ratio; and cortical bone porosity), dual-energy X-ray absorptiometry (hip and spine bone mineral density [BMD]), and peripheral quantitative computed tomography (tibia trabecular and cortical BMD; calf muscle cross-sectional area).

RESULTS

Intention-to-treat analysis did not show any significant changes in outcomes associated with LIV. Subjects using the active device and with greater than the median adherence (70%) demonstrated an increase in distal tibia stiffness (5.3%), trabecular number (1.7%), BMD (2.3%), and plate-to-rod ratio (6.5%), and a decrease in trabecular separation (-1.8%). Changes in calf muscle cross-sectional area were associated with changes in distal tibia stiffness (R = 0.85), trabecular bone volume/total volume (R = 0.91), number (R = 0.92), and separation (R = -0.94) in the active group but not in the placebo group. Baseline parathyroid hormone levels were positively associated with increased cortical bone porosity over the 6-month study period in the placebo group (R = 0.55) but not in the active group (R = 0.01). No changes were observed in the nondistal tibia locations for either group except a decrease in hip BMD in the placebo group (-1.7%).

CONCLUSION

Outcomes and adherence thresholds identified from this pilot study could guide future longitudinal studies involving vibration therapy.

Leg lean mass correlates with exercise systemic output in young Fontan patients

OBJECTIVE

We previously described lower leg lean mass Z-scores (LLMZ) in Fontan patients associated with worse peak oxygen consumption on metabolic exercise testing. We hypothesised that LLMZ correlates with indexed systemic flow (Qsi) and cardiac index (CI) on exercise cardiac magnetic resonance (eCMR).

METHODS

Thirteen patients had LLM measured by dual-energy X-ray absorptiometry within mean 40 (range 0-258) days of eCMR. LLM was converted to sex and race-specific Z-scores based on healthy reference data. Ventricular volumes and flow measurements of the ascending and descending (DAO) aorta and superior vena cava (SVC) were obtained by CMR at rest and just after supine ergometer exercise to a heart rate associated with anaerobic threshold on prior exercise test. Baseline and peak exercise measures of Qsi (SVC+DAO/BSA) and CI, as well as change in Qsi and CI with exercise, were compared with LLMZ by linear regression.

RESULTS

LLMZ was not correlated with resting flows, stroke volume or CI. There was a strong linear correlation between LLMZ and change in both CI (r=0.77, p=0.002) and Qsi (r=0.73, p=0.005) from rest to exercise. There was also a significant correlation between LLMZ and Qsi at exercise (r=0.70, p=0.008). The correlation between LLMZ and CI at exercise did not reach significance (r=0.3, p=0.07).

CONCLUSIONS

In our cohort, there was a strong linear correlation between LLMZ and change in both CI and Qsi from rest to exercise, suggesting that Fontan patients with higher LLMZ may be better able to augment systemic output during exercise, improving performance.

Muscle Deficits in Rheumatoid Arthritis Contribute to Inferior Cortical Bone Structure and Trabecular Bone Mineral Density

OBJECTIVE

Rheumatoid arthritis (RA) is associated with muscle loss, osteoporosis, and fracture. We examined associations between skeletal muscle mass, strength, and quality and trabecular and cortical bone deficits in patients with RA and healthy controls.

METHODS

Participants, ages 18-75 years, completed whole-body dual-energy x-ray absorptiometry and peripheral quantitative computed tomography (pQCT) of the tibia to quantify appendicular lean mass and fat mass indices (ALMI, FMI), muscle density at the lower leg, trabecular bone density, and cortical bone thickness. Age-, sex-, and race-specific Z scores were calculated based on distributions in controls. Associations between body composition and pQCT bone outcomes were assessed in patients with RA and controls. Linear regression analyses assessed differences in bone outcomes after considering differences in body mass index (BMI) and body composition.

RESULTS

The sample consisted of 112 patients with RA (55 men) and 412 controls (194 men). Compared to controls, patients with RA had greater BMI Z score (p < 0.001), lower ALMI Z score after adjustment for FMI (p = 0.02), lower muscle strength Z score (p = 0.01), and lower muscle density Z score (p < 0.001). Among RA, ALMI Z scores were positively associated with trabecular density [β: 0.29 (0.062-0.52); p = 0.01] and cortical thickness [β: 0.33 (0.13-0.53; p = 0.002]. Associations were similar in controls. Bone outcomes were inferior in patients with RA after adjusting for BMI, but similar to controls when adjusting for body composition. Radiographic damage and higher adiponectin levels were independently associated with inferior bone outcomes.

CONCLUSION

Patients with RA exhibit deficits in cortical bone structure and trabecular density at the tibia and a preserved functional muscle-bone unit. A loss of mechanical loading may contribute to bone deficits.

Assessment of muscle mass relative to fat mass and associations with physical functioning in rheumatoid arthritis

Objectives

To determine whether a novel measure of appendicular lean mass relative to fat mass is associated with physical functioning in RA.

Methods

In a cross-sectional design, three independent RA cohorts were retrospectively analysed. Whole-body DXA measures of appendicular lean mass index (ALMI, kg/m 2 ) and fat mass index (FMI, kg/m 2 ) were converted to age, sex and race-specific Z-scores using published National Health and Nutrition Examination Survey reference ranges. Adiposity-adjusted ALMI Z-scores (ALMI FMI ) were determined using a published method to adjust for normal associations between ALMI and FMI Z-scores. Associations between ALMI Z-scores, ALMI FMI Z-scores and physical functioning were assessed after adjusting for age, sex and study. Functional outcomes assessed included the HAQ, Valued Life Activities assessment and Short Physical Performance Battery. Low lean for age was defined as a Z-score of -1 or less.

Results

Our sample consisted of 442 patients with RA. The combined cohort had a mean ALMI Z-score of - 0.51 (1.08) and a mean ALMI FMI Z-score of - 0.58 (1.53), suggesting muscle mass deficits compared with a nationally representative sample. Greater ALMI FMI Z-scores demonstrated stronger associations with better functional outcomes compared with ALMI Z-scores. Associations were not attenuated with adjustment for systemic inflammation or pain. The FMI Z-score was independently associated with physical functioning, with a stronger association seen among patients with greater FMI Z-score. Adiposity-adjusted definitions of low lean mass more clearly identified those with functional impairment.

Conclusion

Estimates of appendicular lean mass that are adjusted for adiposity demonstrate stronger positive associations with functional outcomes compared with unadjusted estimates.

Oral glucocorticoid use and osteonecrosis in children and adults with chronic inflammatory diseases: a population-based cohort study

OBJECTIVES

We studied oral glucocorticoids and osteonecrosis, a rare but serious bone disease, in individuals with various chronic inflammatory diseases. We hypothesised that we would find stronger associations in adults versus children and in people with autoimmune diseases.

DESIGN

Retrospective cohort study.

SETTING

Population-representative data (1994-2013) from general practices in the UK.

PARTICIPANTS

Children and adults diagnosed with asthma; inflammatory bowel disease; juvenile, psoriatic or rheumatoid arthritis; psoriasis; or systemic lupus.

EXPOSURES

Oral glucocorticoid patterns.

PRIMARY AND SECONDARY OUTCOME MEASURES

Diagnosed osteonecrosis (primary) and osteonecrosis plus clinical features (eg, symptoms, pain medication, surgical repair) (secondary). Discrete time failure models estimated the adjusted hazard ratio (aHR) of incident osteonecrosis following oral glucocorticoid exposure. Hypothesis testing was one sided (with corresponding 90% CI) since glucocorticoids were unlikely protective.

RESULTS

After adjusting for demographic, disease-related and health utilisation factors, glucocorticoid exposure was associated with osteonecrosis in adults (ages 18-49, aHR 2.1 (90% CI 1.5 to 2.9); ages ≥50, aHR 1.3 (90% CI 1.01 to 1.7)). However, low-dose glucocorticoids, corresponding to average doses <7.5 mg prednisolone daily and maximum doses <30 mg daily, were not associated with osteonecrosis in adults. Furthermore, even at high glucocorticoid doses, there was no evidence of increased osteonecrosis among glucocorticoid-exposed children (p=0.04 for interaction by age) (any glucocorticoid exposure, ages 2-9: aHR 1.1 (90% CI 0.7 to 1.7); ages 10-17: aHR 0.6 (90% CI 0.3 to 1.6)). Arthritis, inflammatory bowel disease and lupus were independently associated with osteonecrosis, but there was a similar dose relationship between glucocorticoids and osteonecrosis among adults with low-risk and high-risk diseases.

CONCLUSIONS

Glucocorticoid use was clearly associated with osteonecrosis in a dose-related fashion in adults, especially young adults, but this risk was not detectable in children. The absolute risk of glucocorticoid-associated osteonecrosis in the general paediatric population and in adults taking low glucocorticoid doses is at most extremely small.

Assessment of Sex Differences in Fracture Risk Among Patients With Anorexia Nervosa: A Population-Based Cohort Study Using The Health Improvement Network

Though previous studies have demonstrated an increased fracture risk in females with anorexia nervosa (AN), fracture risk in males is not well characterized. The objective of this study was to examine sex differences in fracture risk and site-specific fracture incidence in AN. We performed a population-based retrospective cohort study using The Health Improvement Network (THIN; a large database of anonymized electronic medical records collected at primary care clinics throughout the United Kingdom). The median calendar year for the start of the observation period was 2004-2005. We identified 9239 females and 556 males <60 years of age with AN, and 97,889 randomly selected sex-, age-, and practice-matched participants without eating disorders (92,329 females and 5560 males). Multivariable Cox regression was used to estimate the hazard ratio (HR) for incident fracture. Median age at start of observation was 29.8 years in females and 30.2 years in males. The HR for fracture associated with AN differed by sex and age (interaction p = 0.002). Females with AN had an increased fracture risk at all ages (HR, 1.59; 95% confidence interval [CI], 1.45 to 1.75). AN was associated with a higher risk of fracture among males >40 years of age (HR, 2.54; 95% CI, 1.32 to 4.90; p = 0.005) but not among males ≤40 years. Females with AN had a higher risk of fracture at nearly all anatomic sites. The greatest excess fracture risk was noted at the hip/femur (HR, 5.59; 95% CI, 3.44 to 9.09) and pelvis (HR, 4.54; 95% CI, 2.42 to 8.50) in females and at the vertebrae (HR, 7.25; 95% CI, 1.21 to 43.45) for males with AN. AN was associated with higher incident fracture risk in females across all age groups and in males >40 years old. Sites of highest fracture risk include the hip/femur and pelvis in females and vertebrae in males with AN. © 2016 American Society for Bone and Mineral Research.

Assessment of sex differences in bone deficits among adolescents with anorexia nervosa

OBJECTIVE

The objective of this study was to compare sex differences in bone deficits among adolescents with anorexia nervosa (AN) and to identify other correlates of bone health.

METHOD

Electronic medical records of all patients 9-20 years of age with a DSM-5 diagnosis of AN who were evaluated by the eating disorders program at Stanford with dual-energy X-ray absorptiometry (DXA) between March 1997 and February 2011 were retrospectively reviewed. Whole body bone mineral content Z-scores and bone mineral density (BMD) Z-scores at multiple sites were recorded using the Bone Mineral Density in Childhood Study (BMDCS) reference data.

RESULTS

A total of 25 males and 253 females with AN were included, with median age 15 years (interquartile range [IQR] 14-17) and median duration of illness 9 months (IQR 5-13). Using linear regression analyses, no significant sex differences in bone deficits were found at the lumbar spine, total hip, femoral neck, or whole body when controlling for age, %mBMI, and duration of illness. Lower %mBMI was significantly associated with bone deficits at all sites in adjusted models.

DISCUSSION

This is the first study to evaluate sex differences in bone health among adolescents with AN, using novel DSM-5 criteria for AN and robust BMDCS reference data. We find no significant sex differences in bone deficits among adolescents with AN except for a higher proportion of females with femoral neck BMD Z-scores <-1. Degree of malnutrition was correlated with bone deficits at all sites. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:352-358).

Effect of Exercise and Antidepressants on Skeletal Outcomes in Adolescent Girls With Anorexia Nervosa

PURPOSE

We examined the relationships between malnutrition, lifestyle factors, and bone health in anorexia nervosa (AN) via dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT).

METHODS

Seventy adolescent girls with AN and 132 normal-weighted controls underwent pQCT tibial measures including trabecular volumetric bone mineral density (vBMD), cortical vBMD, and cortical thickness. Participants with AN underwent DXA measures of the axial skeleton. We assessed the association of DXA and pQCT measures with clinical and lifestyle variables.

RESULTS

Body mass index Z-score and ideal body weight percentage were positively correlated with trabecular vBMD, cortical CSA, and section modulus (p < .04). Exercise was associated with all pQCT measures but only with hip BMD by DXA. In AN, the use of antidepressants was associated with lower pQCT measures (p < .03).

CONCLUSIONS

Antidepressants may negatively, and exercise positively, influence BMD in adolescents with eating disorders. These findings offer a provocative look at two longstanding questions.

Effect of high-dose cholecalciferol (vitamin D3) on bone and body composition in children and young adults with HIV infection: a randomized, double-blind, placebo-controlled trial

It is unknown whether vitamin D supplementation positively impacts body composition and bone outcomes in children and young adults with HIV. This RCT found that despite increasing 25(OH)D concentrations, high dose vitamin D₃ supplementation did not impact bone or body composition in children and young adults with HIV infection.

INTRODUCTION

The objective of this paper was to determine the impact of high-dose daily cholecalciferol (vitamin D₃) supplementation on body composition and bone density, structure, and strength in children and young adults with perinatally acquired (PHIV) or behaviorally acquired (BHIV) HIV infection.

METHODS

Participants were randomized to receive vitamin D₃ supplementation (7000 IU/day) or placebo for 12 months. Serum 25-hydroxyvitamin D [25(OH)D] concentrations, dual energy X-ray absorptiometry (DXA) of the whole body and lumbar spine, and peripheral quantitative computed tomography (pQCT) of tibia sites were acquired at 0, 6, and 12 months. DXA and pQCT outcomes were expressed as sex- and population-ancestry specific Z-scores relative to age and adjusted for height or tibia length, as appropriate.

RESULTS

Fifty-eight participants (5.0 to 24.9 years) received vitamin D₃ supplements (n = 30) or placebo (n = 28). At enrollment, groups were similar in age, sex, population ancestry, growth status, serum 25(OH)D concentrations, body composition, and size-adjusted bone measures. Median 25(OH)D concentrations were similar (17.3 ng/mL in the vitamin D₃ supplementation group vs 15.6 ng/mL in the placebo group), and both groups had mild bone deficits. At 12 months, 25(OH)D rose significantly in the vitamin D supplementation group but not in the placebo group (26.4 vs 14.8 ng/mL, respectively, p < 0.008). After adjusting for population ancestry, sex, antiretroviral therapy use, and season, there were no significant treatment group differences in bone or body composition outcomes.

CONCLUSIONS

Despite increasing 25(OH)D concentrations, 12 months of high-dose vitamin D₃ supplementation did not impact bone or body composition in children and young adults with HIV infection.

Skeletal outcomes by peripheral quantitative computed tomography and dual-energy X-ray absorptiometry in adolescent girls with anorexia nervosa

We conducted the first comparison of dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) outcomes in adolescent girls with anorexia nervosa. We observed deficits in bone density by both tools. pQCT assessments were associated with many of the same clinical parameters as have been previously established for DXA.

INTRODUCTION

Adolescents with anorexia nervosa (AN) commonly exhibit bone loss, but effects on bone geometry are less clear. We compared measures obtained by DXA and pQCT in girls with AN.

METHODS

Seventy females (age 15.5 ± 1.9 years ) with AN and 132 normal-weighted controls underwent tibial measures by pQCT including trabecular volumetric bone mineral density (vBMD) at the 3 % site, cortical vBMD and dimensions at the 38 % site, and muscle cross-sectional area (CSA) at the 66 % site. Participants with AN also underwent standard DXA measures. Independent t tests compared the pQCT results, while Pearson coefficient assessed correlations among DXA and pQCT measures.

RESULTS

Trabecular vBMD Z-scores were lower in AN compared to controls (AN -0.31 ± 1.42 vs +0.11 ± 1.01, p = 0.01) and cortical vBMD Z-scores were higher (AN +0.18 ± 0.92 vs -0.50 ± 0.88, p < 0.001). Trabecular vBMD and cortical CSA Z-scores positively correlated with DXA BMD Z-scores (r range 0.57-0.82, p < 0.001). Markers of nutritional status positively correlated with Z-scores for trabecular vBMD, cortical CSA, section modulus, and muscle CSA (p < 0.04 for all).

CONCLUSIONS

This study is the first to compare DXA and pQCT measurements in adolescent girls with AN. We observed deficits in BMD by both DXA and pQCT. pQCT assessments correlated well with DXA bone and body composition measures and were associated with many of the same clinical parameters and disease severity markers as have been previously established for DXA. The differences in cortical vBMD merit further study.

Commercially available lifestyle modification program: randomized controlled trial addressing heart and bone health in BRCA1/2+ breast cancer survivors after risk-reducing salpingo-oophorectomy

PURPOSE

The goal of this RCT was to examine the efficacy and safety of a web-based program to improve cardiovascular and bone health outcomes, among 35 BRCA1/2+ breast cancer survivors who underwent prophylactic oophorectomy and thus experienced premature surgical menopause.

METHODS

A 12-month commercially available web-based lifestyle modification program (Precision Nutrition Coaching) was utilized. Cardiovascular fitness, dietary intake, leisure time activity, body composition, bone mineral density, bone structure, and muscle strength were assessed.

RESULTS

Average adherence to all program components was 74.8 %. Women in the intervention group maintained their cardiovascular fitness level over the 12 months (1.1 ± 7.9 %), while the control group significantly decreased fitness capacity (-4.0 ± 7.5 %). There was a significant difference between groups in percent change of whole body bone area (-0.8 ± 2.5 control and 0.5 ± 1.30 intervention). We also observed decreased BMI (-4.7 ± 6.2 %) and fat mass (-8.6 ± 12.7 %) in the intervention group due to significant concomitant decreases in caloric intake and increases in caloric expenditure. The control group demonstrated decreased caloric intake and decreased lean tissue mass.

CONCLUSIONS

In this population at high risk for detrimental cardiovascular and bone outcomes, a commercially available lifestyle intervention program mitigated a decline in cardiovascular health, improved bone health, and decreased weight through fat loss.

IMPLICATIONS FOR CANCER SURVIVORS

Precision Nutrition Coaching has shown benefit in breast cancer survivors for reduced risk of deleterious cardiovascular and bone outcomes.

Development of Novel Methods to Define Deficits in Appendicular Lean Mass Relative to Fat Mass

Background

Recent studies suggest that adjustment of measures of lean mass for adiposity improves associations with physical function. Our objective was to develop and test a method to adjust appendicular lean mass for adiposity.

Methods

Whole-body DXA data in 14,850 adults in the National Health and Nutrition Examination Survey were used to generate sex-, and race-specific standard deviation scores (Z-Scores relative to age and T-scores relative to 25 year-olds) for appendicular lean mass index (ALMI, kg/m²) and fat mass index (FMI, kg/m²). Correlations between ALMI and FMI Z- and T-Scores were assessed within demographic categories. Fat-adjusted ALMI (ALMI_FMI) scores were determined using residual methods. Sarcopenia was defined as a T-Score <-2.0 and low lean for age as a Z-Score <-1.0. Correlations with physical function were assessed in an at-risk population.

Results

Positive associations between ALMI and FMI Z- and T-Scores were significant (R >0.50; p<0.001) within all demographic categories. The impact of a unit greater FMI Z-score on ALMI Z-score was less in the elderly, men, white subjects, and among individuals with lower FMI (all tests for interaction p<0.001). There was fair agreement between ALMI and ALMI_FMI estimates of sarcopenia and low lean for age [Kappa: 0.46, 0.52, respectively (p<0.0001)]. Elderly subjects were likely to be re-classified as sarcopenic while young subjects were likely to be re-classified as normal using ALMI_FMI. ALMI_FMI T-scores resulted in approximately twice the number of subjects defined as sarcopenic, compared with ALMI T-Scores. (1299 v. 534). Among rheumatoid arthritis patients, ALMI_FMI Z-scores correlated with physical function (Health Assessment Questionnaire: rho = -0.22, p = 0.04; Short Physical Performance Battery: rho = 0.27, p = 0.01); however, the ALMI Z-Score did not.

Conclusions

Adjustment of ALMI for the confounding association with FMI impacts the definition of lean mass deficits. These methods provide a practical tool for investigators and clinicians based on population-based reference data.

Children with lower respiratory tract infections and serum 25-hydroxyvitamin D3 levels: A case-control study

BACKGROUND

Pneumonia is the leading cause of death in children under age of 5 years worldwide. The role of vitamin D in respiratory infections including pneumonia is unclear; therefore, we aimed to determine if children with lower respiratory tract infections had low serum 25-hydroxyvitamin D₃ .

METHODS

We performed a case-control study of children ages 3-60 months from the Guatemala City metropolitan area, hospitalized with community-acquired pneumonia between September and December 2012. Controls were selected from the well-baby/care immunization clinics serving the population from which cases emerged. We analyzed serum 25-hydroxyvitamin D₃ levels and conducted parental interviews to assess subject age, sex, race, feeding type, vitamin D supplementation, frequency of sun exposure, and maternal education. Height and weight were ascertained from medical records. Complete information was available for 70 (83%) of 84 eligible cases and 68 (60%) of 113 eligible controls.

RESULTS

The median (IQR) serum 25-hydroxyvitamin D₃ concentration for cases was 23.2 ng/ml (14.4-29.9) compared to 27.5 ng/ml (21.4-32.3) in controls (P = 0.006). Multiple regression analysis using an a priori cut-point for vitamin D of <20 ng/ml showed that children with lower respiratory tract infections were more likely to have low 25-hydroxyvitamin D₃ levels than controls (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.2, P = 0.02).

CONCLUSIONS

Children with lower respiratory tract infections in Guatemala had low 25-hydroxyvitamin D₃ levels. Pediatr Pulmonol. 2016;51:1080-1087. © 2016 Wiley Periodicals, Inc.

Declining Rates of Inpatient Parathyroidectomy for Primary Hyperparathyroidism in the US

Parathyroidectomy is the only curative therapy for patients with primary hyperparathyroidism. However, the incidence, correlates and consequences of parathyroidectomy for primary hyperparathyroidism across the entire US population are unknown. We evaluated temporal trends in rates of inpatient parathyroidectomy for primary hyperparathyroidism, and associated in-hospital mortality, length of stay, and costs. We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) from 2002–2011. Parathyroidectomies for primary hyperparathyroidism were identified using International Classification of Diseases, Ninth Revision codes. Unadjusted and age- and sex- adjusted rates of inpatient parathyroidectomy for primary hyperparathyroidism were derived from the NIS and the annual US Census. We estimated 109,583 parathyroidectomies for primary hyperparathyroidism between 2002 and 2011. More than half (55.4%) of patients were younger than age 65, and more than three-quarters (76.8%) were female. The overall rate of inpatient parathyroidectomy was 32.3 cases per million person-years. The adjusted rate decreased from 2004 (48.3 cases/million person-years) to 2007 (31.7 cases/million person-years) and was sustained thereafter. Although inpatient parathyroidectomy rates declined over time across all geographic regions, a steeper decline was observed in the South compared to other regions. Overall in-hospital mortality rates were 0.08%: 0.02% in patients younger than 65 years and 0.14% in patients 65 years and older. Inpatient parathyroidectomy rates for primary hyperparathyroidism have declined in recent years.

Rates and Outcomes of Parathyroidectomy for Secondary Hyperparathyroidism in the United States

BACKGROUND AND OBJECTIVES

Secondary hyperparathyroidism is common among patients with ESRD. Although medical therapy for secondary hyperparathyroidism has changed dramatically over the last decade, rates of parathyroidectomy for secondary hyperparathyroidism across the United States population are unknown. We examined temporal trends in rates of parathyroidectomy, in-hospital mortality, length of hospital stay, and costs of hospitalization.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample, a representative national database on hospital stay regardless of age and payer in the United States, we identified parathyroidectomies for secondary hyperparathyroidism from 2002 to 2011. Data from the US Renal Data System reports were used to calculate the rate of parathyroidectomy.

RESULTS

We identified 32,971 parathyroidectomies for secondary hyperparathyroidism between 2002 and 2011. The overall rate of parathyroidectomy was approximately 5.4/1000 patients (95% confidence interval [95% CI], 5.0/1000 to 6.0/1000). The rate decreased from 2003 (7.9/1000 patients; 95% CI, 6.2/1000 to 9.6/1000), reached a nadir in 2005 (3.3/1000 patients; 95% CI, 2.6/1000 to 4.0/1000), increased again through 2006 (5.4/1000 patients; 95% CI, 4.4/1000 to 6.4/1000), and remained stable since that time. Rates of in-hospital mortality decreased from 1.7% (95% CI, 0.8% to 2.6%) in 2002 to 0.8% (95% CI, 0.1% to 1.6%) in 2011 (P for trend <0.001). In-hospital mortality rates were significantly higher in patients with heart failure (odds ratio [OR], 4.23; 95% CI, 2.59 to 6.91) and peripheral vascular disease (OR, 4.59; 95% CI, 2.75 to 7.65) and lower among patients with prior kidney transplantation (OR, 0.20; 95% CI, 0.06 to 0.65).

CONCLUSIONS

Despite the use of multiple medical therapies, rates of parathyroidectomy of secondary hyperparathyroidism have not declined in recent years.

Effect of Low-Magnitude Mechanical Stimuli on Bone Density and Structure in Pediatric Crohn's Disease: A Randomized Placebo-Controlled Trial

Pediatric Crohn's Disease (CD) is associated with low trabecular bone mineral density (BMD), cortical area, and muscle mass. Low-magnitude mechanical stimulation (LMMS) may be anabolic. We conducted a 12-month randomized double-blind placebo-controlled trial of 10 minutes daily exposure to LMMS (30 Hz frequency, 0.3 g peak-to-peak acceleration). The primary outcomes were tibia trabecular BMD and cortical area by peripheral quantitative CT (pQCT) and vertebral trabecular BMD by QCT; additional outcomes included dual-energy X-ray absorptiometry (DXA) whole body, hip and spine BMD, and leg lean mass. Results were expressed as sex-specific Z-scores relative to age. CD participants, ages 8 to 21 years with tibia trabecular BMD <25th percentile for age, were eligible and received daily cholecalciferol (800 IU) and calcium (1000 mg). In total, 138 enrolled (48% male), and 121 (61 active, 60 placebo) completed the 12-month trial. Median adherence measured with an electronic monitor was 79% and did not differ between arms. By intention-to-treat analysis, LMMS had no significant effect on pQCT or DXA outcomes. The mean change in spine QCT trabecular BMD Z-score was +0.22 in the active arm and -0.02 in the placebo arm (difference in change 0.24 [95% CI 0.04, 0.44]; p = 0.02). Among those with >50% adherence, the effect was 0.38 (95% CI 0.17, 0.58, p < 0.0005). Within the active arm, each 10% greater adherence was associated with a 0.06 (95% CI 0.01, 1.17, p = 0.03) greater increase in spine QCT BMD Z-score. Treatment response did not vary according to baseline body mass index (BMI) Z-score, pubertal status, CD severity, or concurrent glucocorticoid or biologic medications. In all participants combined, height, pQCT trabecular BMD, and cortical area and DXA outcomes improved significantly. In conclusion, LMMS was associated with increases in vertebral trabecular BMD by QCT; however, no effects were observed at DXA or pQCT sites. © 2016 American Society for Bone and Mineral Research.

Comparison of Two ELISA Methods and Mass Spectrometry for Measurement of Vitamin D-Binding Protein: Implications for the Assessment of Bioavailable Vitamin D Concentrations Across Genotypes

Studies using vitamin D-binding protein (DBP) concentrations to estimate free and bioavailable vitamin D have increased dramatically in recent years. Combinations of two single-nucleotide polymorphisms (SNPs) produce three major DBP isoforms (Gc1f, Gc1s, and Gc2). A recent study showed that DBP concentrations quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) did not differ by race, whereas a widely used monoclonal enzyme-linked immunosorbent assay (ELISA) quantified DBP differentially by isoform, yielding significantly lower DBP concentrations in black versus white individuals. We compared measurements of serum DBP using a monoclonal ELISA, a polyclonal ELISA, and LC-MS/MS in 125 participants in the Chronic Renal Insufficiency Cohort (CRIC). Serum free and bioavailable 25OHD were calculated based on DBP concentrations from these three assays in homozygous participants, and race differences were compared. We confirmed that the monoclonal ELISA quantifies DBP differentially by isoform and showed that the polyclonal ELISA is not subject to this bias. Whereas ≤9% of the variability in DBP concentrations quantified using either LC-MS/MS or the polyclonal ELISA was explained by genotype, 85% of the variability in the monoclonal ELISA-based measures was explained by genotype. DBP concentrations measured by the monoclonal ELISA were disproportionately lower than LC-MS/MS-based results for Gc1f homozygotes (median difference -67%; interquartile range [IQR] -71%, -64%), 95% of whom were black. In contrast, the polyclonal ELISA yielded consistently and similarly higher measurements of DBP than LC-MS/MS, irrespective of genotype, with a median percent difference of +50% (IQR +33%, +65%). Contrary to findings using the monoclonal ELISA, DBP concentrations did not differ by race, and free and bioavailable 25OHD were significantly lower in black versus white participants based on both the polyclonal ELISA and LC-MS/MS, consistent with their lower total 25OHD. Future studies of DBP and free or bioavailable vitamin D metabolites should employ DBP assays that are not biased by DBP genotype. © 2016 American Society for Bone and Mineral Research.