Impact of osteoporosis and osteoporosis medications on fracture healing: a narrative review

Antiresorptive medications do not negatively affect fracture healing in humans. Teriparatide may decrease time to fracture healing. Romosozumab has not shown a beneficial effect on human fracture healing.

BACKGROUND

Fracture healing is a complex process. Uncertainty exists over the influence of osteoporosis and the medications used to treat it on fracture healing.

METHODS

Narrative review authored by the members of the Fracture Working Group of the Committee of Scientific Advisors of the International Osteoporosis Foundation (IOF), on behalf of the IOF and the Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT).

RESULTS

Fracture healing is a multistep process. Most fractures heal through a combination of intramembranous and endochondral ossification. Radiographic imaging is important for evaluating fracture healing and for detecting delayed or non-union. The presence of callus formation, bridging trabeculae, and a decrease in the size of the fracture line over time are indicative of healing. Imaging must be combined with clinical parameters and patient-reported outcomes. Animal data support a negative effect of osteoporosis on fracture healing; however, clinical data do not appear to corroborate with this. Evidence does not support a delay in the initiation of antiresorptive therapy following acute fragility fractures. There is no reason for suspension of osteoporosis medication at the time of fracture if the person is already on treatment. Teriparatide treatment may shorten fracture healing time at certain sites such as distal radius; however, it does not prevent non-union or influence union rate. The positive effect on fracture healing that romosozumab has demonstrated in animals has not been observed in humans.

CONCLUSION

Overall, there appears to be no deleterious effect of osteoporosis medications on fracture healing. The benefit of treating osteoporosis and the urgent necessity to mitigate imminent refracture risk after a fracture should be given prime consideration. It is imperative that new radiological and biological markers of fracture healing be identified. It is also important to synthesize clinical and basic science methodologies to assess fracture healing, so that a convergence of the two frameworks can be achieved.

The global approach to rehabilitation following an osteoporotic fragility fracture: A review of the rehabilitation working group of the International Osteoporosis Foundation (IOF) committee of scientific advisors

PURPOSE

To conduct a review of the current state of the evidence for rehabilitation strategies post-fragility fracture.

METHODS

Narrative review conducted by the Rehabilitation Working Group of the International Osteoporosis Foundation Committee of Scientific Advisors characterizing the range of rehabilitation modalities instrumental for the management of fragility fractures.

RESULTS

Multi-modal exercise post-fragility fracture to the spine and hip is strongly recommended to reduce pain, improve physical function, and improve quality of life. Outpatient physiotherapy post-hip fracture has a stronger evidence base than outpatient physiotherapy post-vertebral fracture. Appropriate nutritional care after fragility fracture provides a large range of improvement in morbidity and mortality. Education increases understanding of osteoporosis which in turn increases utilization of other rehabilitation services. Education may improve other health outcomes such as pain and increase a patient's ability for self-advocacy.

CONCLUSION

Rehabilitation interventions are inter-reliant, and research investigating the interaction of exercise, nutrition, and other multi-modal therapies may increase the relevance of rehabilitation research to clinical care.

Reference microarchitectural values measured by HR-pQCT in a Franco-Swiss cohort of young adult women

Bone microarchitecture assessed by high-resolution peripheral quantitative computed tomography varies across populations of different origin. The study presents a reference dataset of microarchitectural parameters in a homogeneous group of participants aged within 22-27 range determined by a discriminant analysis of a larger cross-sectional cohort of 339 women.

INTRODUCTION

High-resolution peripheral quantitative computed tomography (HR-pQCT) non-invasively measures three-dimensional bone microarchitectural parameters and volumetric bone mineral density. Previous studies established normative reference HR-pQCT datasets for several populations, but there were few data assessed in a reference group of young women with Caucasian ethnicity living in Western Europe. It is important to obtain different specific reference dataset for a valid interpretation of cortical and trabecular microarchitecture data. The aim of our study was to find the population with the most optimal bone status in order to establish a descriptive reference HR-pQCT dataset in a young and healthy normal-weight female cohort living in a European area including Geneva, Switzerland, Lyon and Saint-Etienne, France.

METHODS

We constituted a cross-sectional cohort of 339 women aged 19-41 years with a BMI > 18 and < 30 kg/m². All participants had HR-pQCT measurements at both non-dominant distal radius and tibia sites.

RESULTS

We observed that microarchitectural parameters begin to decline before the age of 30 years. Based on a discriminant analysis, the optimal bone profile in this population was observed between the age range of 22 to 27 years. Consequently, we considered 43 participants aged 22-27 years to establish a reference dataset with median values and percentiles.

CONCLUSION

This is the first study providing reference values of HR-pQCT measurements considering specific age bounds in a Franco-Swiss female cohort at the distal radius and tibia sites.

How can the orthopedic surgeon ensure optimal vitamin D status in patients operated for an osteoporotic fracture?

In this narrative review, the role of vitamin D deficiency in the pathophysiology, healing of fragility fractures, and rehabilitation is discussed. Vitamin D status can be assessed by measuring serum 25(OH)-vitamin D level with standardized assays. There is a high prevalence of vitamin D insufficiency (25(OH)D < 50 nmol/l (i.e., 20 ng/mL)) or deficiency (25(OH)D < 25 nmol/l (i.e., 10 ng/mL)) in patients with fragility fractures and especially in those with a hip fracture. The evidence on the effects of vitamin D deficiency and/or vitamin D supplementation on fracture healing and material osseointegration is still limited. However, it appears that vitamin D have a rather positive influence on these processes. The fracture liaison service (FLS) model can help to inform orthopedic surgeons, all caregivers, and fractured patients about the importance of optimal vitamin D status in the management of patients with fragility fractures. Therefore, vitamin D status should be included in Capture the Fracture® program as an outcome of FLS in addition to dual-energy X-ray absorptiometry (DXA) and specific antiosteoporosis medication. Vitamin D plays a significant role in the pathophysiology and healing of fragility fractures and in rehabilitation after fracture. Correction of vitamin D deficiency should be one of the main outcomes in fracture liaison services.

Higher rates of osteoporosis treatment initiation and persistence in patients with newly diagnosed vertebral fracture when introduced in inpatients than later in outpatients

Whether in-hospital management of patients with newly identified vertebral fractures leads to a higher rate of osteoporosis medication than delayed outpatient management remains unknown. Our study showed that early osteoporosis therapy initiation in a fracture liaison service during hospital stay was a more efficacious strategy for secondary fracture prevention.

INTRODUCTION

Fracture liaison services are standard care for secondary fracture prevention. A higher rate of osteoporosis treatment initiation may be considered when introduced in the hospital rather than an outpatient recommendation to a primary care physician (PCP). Whether this applies to patients with newly detected vertebral fractures in a general internal medicine ward remains unknown. We prospectively investigated whether in-hospital management of newly identified vertebral fractures led to a higher rate of osteoporosis medication initiation and persistence at 3 and 6 months than delayed outpatient management by a PCP.

METHODS

We conducted a prospective study including hospitalized patients > 60 years systematically searched for asymptomatic vertebral fractures on lateral chest and/or abdominal radiographs. Patients were included either in phase 1 (outpatient care recommendations on osteoporosis management to a PCP) or in phase 2 (inpatient care management initiated during hospitalization). The percentage of patients under osteoporosis treatment was evaluated by telephone interview at 3 and 6 months.

RESULTS

Outpatients' (84 with fracture/407 assessed (21%); 75.7 ± 7.7 years) and inpatients' (100/524 (19%); 77.8 ± 9.4 years) characteristics were similar. Osteoporosis medication was more often prescribed in inpatients at 3 (67% vs. 19%, respectively; p < 0.001) and 6 months (69 vs. 27%, respectively; p < 0.001). The percentage under treatment was also higher in inpatients than in outpatients at 3 (52 vs. 19%, p < 0.001) and 6 months (54 vs. 22%, p < 0.001). Length of stay and destination post-discharge were not different between groups.

CONCLUSIONS

Early patient management after a newly detected vertebral fracture during hospitalization was a more efficacious strategy of secondary fracture prevention than delayed outpatient management following discharge.

Associations between radius low-frequency axial ultrasound velocity and bone fragility in elderly men and women

An exploratory study in elderly women and men from the Geneva Retirees Cohort indicates that low-frequency quantitative ultrasound measurement at the radius captures aBMD, bone size, and cortical tissue mineral density and might be used for screening purposes prior to DXA to evaluate fracture risk_. INTRODUCTION: The contribution of distal radius bone mineral density (BMD) and cortical microstructure to fracture risk has recently been demonstrated. In this exploratory study, we investigated whether low-frequency quantitative ultrasound measurement at the distal radius may capture the peripheral determinants of bone fragility assessed with dual-energy X-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT).

METHODS

Low-frequency velocity (V_LF) was measured at the radius using OsCare Sono®, a portable axial transmission ultrasonometer, in 271 community-dwelling postmenopausal women and men (age 71.5 ± 1.4 years) from the Geneva Retirees Cohort. Cortical (Ct) and trabecular (Tb) volumetric (v) BMD and microstructure at the distal radius were assessed by HR-pQCT, in addition to areal (a) BMD by DXA, at the same time point.

RESULTS

V_LF was highly correlated with aBMD at the distal third radius (r = 0.72, p < 0.001). For microstructure parameters, the highest correlation was observed with cortical area (r = 0.59, p < 0.001). V_LF also captured bone geometry (total area) and cortical tissue mineral density independently of aBMD. In models adjusted for age and sex, V_LF was significantly associated with prevalent low-trauma fractures [OR 95%CI for one SD decrease of V_LF 1.50 (1.05, 2.14), p = 0.024], with discrimination performance comparable to femoral neck or distal radius aBMD.

CONCLUSION

Measurement of V_LF at the radius captures aBMD, bone size, and cortical tissue mineral density and might be used for screening purposes prior to DXA to evaluate fracture risk_.

Fermented dairy products consumption is associated with attenuated cortical bone loss independently of total calcium, protein, and energy intakes in healthy postmenopausal women

A longitudinal analysis of bone microstructure in postmenopausal women of the Geneva Retirees Cohort indicates that age-related cortical bone loss is attenuated at non-bearing bone sites in fermented dairy products consumers, not in milk or ripened cheese consumers, independently of total energy, calcium, or protein intakes.

INTRODUCTION

Fermented dairy products (FDP), including yogurts, provide calcium, phosphorus, and proteins together with prebiotics and probiotics, all being potentially beneficial for bone. In this prospective cohort study, we investigated whether FDP, milk, or ripened cheese consumptions influence age-related changes of bone mineral density (BMD) and microstructure.

METHODS

Dietary intakes were assessed at baseline and after 3.0 ± 0.5 years with a food frequency questionnaire in 482 postmenopausal women enrolled in the Geneva Retirees Cohort. Cortical (Ct) and trabecular (Tb) volumetric (v) BMD and microstructure at the distal radius and tibia were assessed by high-resolution peripheral quantitative computerized tomography, in addition to areal (a) BMD and body composition by dual-energy X-ray absorptiometry, at the same time points.

RESULTS

At baseline, FDP consumers had lower abdominal fat mass and larger bone size at the radius and tibia. Parathyroid hormone and β-carboxyterminal cross-linked telopeptide of type I collagen levels were inversely correlated with FDP consumption. In the longitudinal analysis, FDP consumption (mean of the two assessments) was associated with attenuated loss of radius total vBMD and of Ct vBMD, area, and thickness. There was no difference in aBMD and at the tibia. These associations were independent of total energy, calcium, or protein intakes. For other dairy products categories, only milk consumption was associated with lower decrease of aBMD and of failure load at the radius.

CONCLUSION

In this prospective cohort of healthy postmenopausal women, age-related Ct bone loss was attenuated at non-bearing bone sites in FDP consumers, not in milk or ripened cheese consumers, independently of total energy, calcium, or protein intakes.

STUDY REGISTRATION

ISRCTN11865958 ( http://www.isrctn.com ).

Interaction between LRP5 and periostin gene polymorphisms on serum periostin levels and cortical bone microstructure

We investigated the interaction between periostin SNPs and the SNPs of the genes assumed to modulate serum periostin levels and bone microstructure in a cohort of postmenopausal women. We identified an interaction between LRP5 SNP rs648438 and periostin SNP rs9547970 on serum periostin levels and on radial cortical porosity.

PURPOSE

The purpose of this study is to investigate the interaction between periostin gene polymorphisms (SNPs) and other genes potentially responsible for modulating serum periostin levels and bone microstructure in a cohort of postmenopausal women.

METHODS

In 648 postmenopausal women from the Geneva Retirees Cohort, we analyzed 6 periostin SNPs and another 149 SNPs in 14 genes, namely BMP2, CTNNB1, ESR1, ESR2, LRP5, LRP6, PTH, SPTBN1, SOST, TGFb1, TNFRSF11A, TNFSF11, TNFRSF11B and WNT16. Volumetric BMD and bone microstructure were measured by high-resolution peripheral quantitative computed tomography at the distal radius and tibia.

RESULTS

Serum periostin levels were associated with radial cortical porosity, including after adjustment for age, BMI, and years since menopause (p = 0.036). Sixteen SNPs in the ESR1, LRP5, TNFRSF11A, SOST, SPTBN1, TNFRSF11B and TNFSF11 genes were associated with serum periostin levels (p range 0.03-0.001) whereas 26 SNPs in 9 genes were associated with cortical porosity at the radius and/or at the tibia. WNT 16 was the gene with the highest number of SNPs associated with both trabecular and cortical microstructure. The periostin SNP rs9547970 was also associated with cortical porosity (p = 0.04). In particular, SNPs in LRP5, ESR1 and near the TNFRSF11A gene were associated with both cortical porosity and serum periostin levels. Eventually, we identified an interaction between LRP5 SNP rs648438 and periostin SNP rs9547970 on serum periostin levels (interaction p = 0.01) and on radial cortical porosity (interaction p = 0.005).

CONCLUSION

These results suggest that periostin expression is genetically modulated, particularly by polymorphisms in the Wnt pathway, and is thereby implicated in the genetic variation of bone microstructure.

Prior ankle fractures in postmenopausal women are associated with low areal bone mineral density and bone microstructure alterations

In a cross-sectional analysis in postmenopausal women, prior ankle fractures were associated with lower areal bone mineral density (BMD) and trabecular bone alterations compared to no fracture history. Compared to women with forearm fractures, microstructure alterations were of lower magnitude. These data suggest that ankle fractures are another manifestation of bone fragility.

INTRODUCTION

Whether ankle fractures represent fragility fractures associated with low areal bone mineral density (aBMD) and volumetric bone mineral density (vBMD) and/or bone microstructure alterations remains unclear, in contrast to the well-recognised association between forearm fractures and osteoporosis. The objective of this study was to investigate aBMD, vBMD and bone microstructure in postmenopausal women with prior ankle fracture in adulthood, compared with women without prior fracture or with women with prior forearm fractures, considered as typically of osteoporotic origin.

METHODS

In a cross-sectional analysis in the Geneva Retirees Cohort study, 63 women with ankle fracture and 59 with forearm fracture were compared to 433 women without fracture (mean age, 65 ± 1 years). aBMD was measured by dual-energy X-ray absorptiometry; distal radius and tibia vBMD and bone microstructure were measured by high-resolution peripheral quantitative computed tomography.

RESULTS

Compared with women without fracture, those with ankle fractures had lower aBMD, radius vBMD (-7.9%), trabecular density (-10.7%), number (-7.3%) and thickness (-4.6%) and higher trabecular spacing (+14.5%) (P < 0.05 for all). Tibia trabecular variables were also altered. For 1 standard deviation decrease in total hip aBMD or radius trabecular density, odds ratios for ankle fractures were 2.2 and 1.6, respectively, vs 2.2 and 2.7 for forearm fracture, respectively (P ≤ 0.001 for all). Compared to women with forearm fractures, those with ankle fractures had similar spine and hip aBMD, but microstructure alterations of lower magnitude.

CONCLUSION

Women with ankle fractures have lower aBMD and vBMD and trabecular bone alterations, suggesting that ankle fractures are another manifestation of bone fragility.

Additive Genetic Effects on Circulating Periostin Contribute to the Heritability of Bone Microstructure

CONTEXT

Genetic factors account for 60-80% of the areal bone mineral density (aBMD) variance, whereas the heritability of bone microstructure is not clearly established. aBMD and microstructure are under the control of osteocytes, which regulate bone formation through the expression of molecules such as sclerostin (SOST) and periostin (POSTN).

OBJECTIVE

We hypothesized that additive genetic effects contribute to serum levels of SOST and POSTN and thereby to the individual variance of bone microstructure.

SUBJECTS AND METHODS

In a retrospective analysis of 432 subjects from the Geneva Retiree Cohort age 64.9 ± 1.4 years and 96 of their offspring age 37.9 ± 5.7 years, we measured serum SOST (sSOST) and serum POSTN (sPOSTN), distal radius and tibia microstructure, hip and lumbar spine aBMD, and bone turnover markers, Heritability (h(2), %) was calculated as twice the slope of the regression (β) between parents and offspring.

RESULTS

cPOSTN levels were significantly higher in men than women and in offspring than parents. h(2) values for bone microstructural traits ranged from 22-64% depending on the envelope (trabecular [Tb] or cortical [Ct]) and skeletal site (radius or tibia), whereas h(2) for sPOSTN and sSOST was 50% and 40%, respectively. sPOSTN was positively associated with Tb bone volume on total volume and Ct thickness, and negatively with Ct porosity. The associations for Ct parameters remain significant after adjustment for propetide of type-I procollagen, cross-linked telopeptide of type I collagen, femoral neck aBMD, sex or age. After adjustment of bone traits for sPOSTN, h(2) values decreased for several Tb and Ct bone parameters, but not for aBMD. In contrast, adjusting for sSOST did not alter h(2) values for bone traits.

CONCLUSIONS

Additive genetic effects account for a substantial proportion of the individual variance of bone microstructure, sPOSTN, and sSOST. sPOSTN is largely inherited as a sex-related trait and carries an important contribution to the heritability of bone microstructure, indicating that these traits are at least partly determined by common genetic effects.

[Bone health in Geneva retirees]

GERICO (Geneva Retirees Cohort) is a cohort of 953 men and women recruited at the age of 65 in Canton of Geneva, Switzerland, providing a picture of bone health at retirement time. Despite few comorbidities and good nutritional intake and vitamin D status, 30% of subjects have a history of vertebral or clinical fracture after the age of 45, 20% of women and 11% of men have osteoporosis assessed by DXA. 22% have a 10-year probability of a major osteoporotic fracture assessed by FRAX greater than 15%, -i.e. the current intervention thresholds recommended in this age-class in Switzerland. Nevertheless, only 1.4% subject benefits of an anti-osteoporotic drug. These data underscore the importance of primary and secondary prevention of osteoporosis and fractures in healthy elderly at time of retirement.

Fracture history of healthy premenopausal women is associated with a reduction of cortical microstructural components at the distal radius

OBJECTIVES

The objective of this study is to determine in healthy premenopausal women with a history of fracture which bone structural components of the distal radius are the most closely associated with a risk of fracture.

METHODS AND PARTICIPANTS

The method was as follows: measurement of radial areal bone mineral density (aBMD) by DXA, microstructural components by high-resolution quantitative peripheral computerized tomography (HR-pQCT) and strength variables by micro Finite Element Analysis (μFEA) in 196 healthy premenopausal women aged 45.9 ± 3.7 (± SD) years with (FX, n = 96) and without (NO-FX, n = 100) a history of fracture. We evaluated differences in T-scores between FX and NO-FX and risk of fracture by Odds ratios (OR with 95% confidence intervals, CI) per one SD decrease, using logistic regression analysis after adjustment for age, height, weight, menarcheal age, calcium and protein intakes, and physical activity.

RESULTS

In the whole group the mean radial metaphysis aBMD T-score was not significantly different from zero. In the FX as compared to the NO-FX group, the differences in T-scores were as follows: for radial metaphysis: aBMD, -0.24 (P = 0.005); for distal radius microstructure components: cortical volumetric BMD, -0.38 (P = 0.0009); cortical thickness, -0.37 (P = 0.0001); cross-sectional area (CSA), +0.24 (P=0.034); and endosteal perimeter, +0.28 (P = 0.032); and for strength estimates: stiffness, -0.15 (P = 0.030); failure load, -0.14 (P = 0.044); and apparent modulus, -0.28 (P = 0.006). T-scores of trabecular volumetric BMD and thickness did not significantly differ between the FX and the NO-FX group. Accordingly, the risk of fracture (OR, 95% CI) for 1 SD decrease in radius bone parameters was as follows: radial metaphysis aBMD: 1.70 (1.18-2.44), P = 0.004; cortical volumetric BMD: 1.86 (1.28-2.71), P = 0.001; and cortical thickness: 2.36 (1.53-3.63), P = 0.0001. The corresponding fracture risk for the strength estimates was as follows: stiffness: 1.66 (1.06-2.61), P = 0.028; failure load: 1.59 (1.02-2.47), P = 0.041; and apparent modulus: 1.76 (1.17-2.64), P = 0.006.

CONCLUSIONS

In healthy premenopausal women, a history of fracture is associated with reduced T-scores in the distal radius, with the cortical components showing the greatest deficit. A reduction of one SD in cortical thickness is associated with a nearly three-fold increased risk of fracture. This finding strengthens the notion that, in healthy women, a certain degree of bone structural fragility contributes to fractures before the menopause and therefore should be taken into consideration in the individual prevention strategy of postmenopausal osteoporosis.

Long-term HIV infection and antiretroviral therapy are associated with bone microstructure alterations in premenopausal women

We evaluated the influence of long-term HIV infection and its treatment on distal tibia and radius microstructure. Premenopausal eumenorrheic HIV-positive women displayed trabecular and cortical microstructure alterations, which could contribute to increased bone fragility in those patients.

INTRODUCTION

Bone fragility is an emerging issue in HIV-infected patients. Dual-energy X-ray absorptiometry (DXA) quantified areal bone mineral density (BMD) predicts fracture risk, but a significant proportion of fracture risk results from microstructural alterations.

METHODS

We studied the influence of long-term HIV infection on bone microstructure as evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT) in 22 HIV-positive (+ve) premenopausal eumenorrheic women and 44 age- and body mass index (BMI)-matched HIV-negative (-ve) controls. All subjects completed questionnaires regarding calcium/protein intakes and physical activity, and underwent DXA and HR-pQCT examinations for BMD and peripheral skeleton microstructure, respectively. A risk factor analysis of tibia trabecular density using linear mixed models was conducted.

RESULTS

In HIV+ve women on successful antiretroviral therapy (undetectable HIV-RNA, median CD4 cell count, 626), infection duration was 16.5 ± 3.5 (mean ± SD) years; median BMI was 22 (IQR, 21-26) kg/m². More HIV+ve women were smokers (82 versus 50 %, p = 0.013). Compared to controls, HIV+ve women had lower lumbar spine (spine T-score -0.70 vs -0.03, p = 0.014), but similar proximal femur BMD. At distal tibia, HIV+ve women had a 14.1 % lower trabecular density and a 13.2 % reduction in trabecular number compared to HIV-ve women (p = 0.013 and 0.029, respectively). HR-pQCT differences in distal radius were significant for cortical density (-3.0 %; p = 0.029).

CONCLUSIONS

Compared with HIV-ve subjects, premenopausal HIV+ve treated women had trabecular and cortical bone alterations. Adjusted analysis revealed that HIV status was the only determinant of between group tibia trabecular density differences. The latter could contribute to increased bone fragility in HIV+ve patients.

Alterations of bone microstructure and strength in end-stage renal failure

End-stage renal disease (ESRD) patients have a high risk of fractures. We evaluated bone microstructure and finite-element analysis-estimated strength and stiffness in patients with ESRD by high-resolution peripheral computed tomography. We observed an alteration of cortical and trabecular bone microstructure and of bone strength and stiffness in ESRD patients.

INTRODUCTION

Fragility fractures are common in ESRD patients on dialysis. Alterations of bone microstructure contribute to skeletal fragility, independently of areal bone mineral density.

METHODS

We compared microstructure and finite-element analysis estimates of strength and stiffness by high-resolution peripheral quantitative computed tomography (HR-pQCT) in 33 ESRD patients on dialysis (17 females and 16 males; mean age, 47.0 ± 12.6 years) and 33 age-matched healthy controls.

RESULTS

Dialyzed women had lower radius and tibia cortical density with higher radius cortical porosity and lower tibia cortical thickness, compared to controls. Radius trabecular number was lower with higher heterogeneity of the trabecular network. Male patients displayed only a lower radius cortical density. Radius and tibia cortical thickness correlated negatively with bone-specific alkaline phosphatase (BALP). Microstructure did not correlate with parathyroid hormone (PTH) levels. Cortical porosity correlated positively with "Kidney Disease: Improving Global Outcomes" working group PTH level categories (r = 0.36, p < 0.04). BMI correlated positively with trabecular number (r = 0.4, p < 0.02) and negatively with trabecular spacing (r = -0.37, p < 0.03) and trabecular network heterogeneity (r = -0.4, p < 0.02). Biomechanics positively correlated with BMI and negatively with BALP.

CONCLUSION

Cortical and trabecular bone microstructure and calculated bone strength are altered in ESRD patients, predominantly in women. Bone microstructure and biomechanical assessment by HR-pQCT may be of major clinical relevance in the evaluation of bone fragility in ESRD patients.

Prevalence of vertebral fracture in oldest old nursing home residents

We evaluated vertebral fracture prevalence using DXA-based vertebral fracture assessment and its influence on the Fracture Risk Assessment (FRAX) tool-determined 10-year fracture probability in a cohort of oldest old nursing home residents. More than one third of the subjects had prevalent vertebral fracture and 50% osteoporosis. Probably in relation with the prevailing influence of age and medical history of fracture, adding these information into FRAX did not markedly modify fracture probability.

INTRODUCTION

Oldest old nursing home residents are at very high risk of fracture. The prevalence of vertebral fracture in this specific population and its influence on fracture probability using the FRAX tool are not known.

METHODS

Using a mobile DXA osteodensitometer, we studied the prevalence of vertebral fracture, as assessed by vertebral fracture assessment program, of osteoporosis and of sarcopenia in 151 nursing home residents. Ten-year fracture probability was calculated using appropriately calibrated FRAX tool.

RESULTS

Vertebral fractures were detected in 36% of oldest old nursing home residents (mean age, 85.9 ± 0.6 years). The prevalence of osteoporosis and sarcopenia was 52% and 22%, respectively. Ten-year fracture probability as assessed by FRAX tool was 27% and 15% for major fracture and hip fracture, respectively. Adding BMD or VFA values did not significantly modify it.

CONCLUSION

In oldest old nursing home residents, osteoporosis and vertebral fracture were frequently detected. Ten-year fracture probability appeared to be mainly determined by age and clinical risk factors obtained by medical history, rather than by BMD or vertebral fracture.

Fractures in healthy females followed from childhood to early adulthood are associated with later menarcheal age and with impaired bone microstructure at peak bone mass

BACKGROUND

Whether fractures observed in healthy children are associated with microstructural alterations and strength deficit that persists by the end of the growth period is not established. Considering the importance of pubertal timing in bone development, we also quantified the fracture risk related to later menarcheal age (MENA).

PARTICIPANTS AND METHODS

We followed 124 healthy girls from mean ± sd age 7.9 ± 0.5 to 20.4 ± 0.6 yr. Fractures, MENA, and radius areal bone mineral density (aBMD) were recorded at regular intervals. At a mean age of 20.4 yr, microstructural and strength variables of the distal radius were determined by high-resolution peripheral computerized tomography and micro-finite element analysis.

RESULTS

Sixty-one fractures occurred in 42 subjects. At 20.4 yr, subjects with fractures had lower aBMD at radial diaphysis (P = 0.005) and metaphysis (P = 0.008), lower distal radius trabecular volumetric density (vBMD) (P = 0.010) and thickness (P = 0.014), and reduction in stiffness (P = 0.013), failure load (P = 0.013), and apparent modulus (P = 0.046). Odds ratios revealed an increased risk of fracture for a 1-sd reduction in radial aBMD diaphysis [1.97 (P = 0.006)] and metaphysis [1.97 (P = 0.008)] and distal radius trabecular vBMD [1.89 (P = 0.011)], thickness [1.97 (P = 0.017)], stiffness [2.02 (P = 0.014)], failure load [2.00 (P = 0.014)], and apparent modulus [1.79 (P = 0.043)]. MENA occurred at a later age in subjects with fractures (P = 0.003). For MENA 1 sd (1.2 yr) later, the increase of fracture risk was 2.1 (P = 0.002).

CONCLUSIONS

In healthy young women, low trabecular vBMD and thickness in the distal radius are associated with reduced bone strength and increased fracture risk during growth. This study also documents that later pubertal timing is associated with increased incidence of fracture during childhood and adolescence.

[Comprehensive geriatric assessment in the emergency department: some usefull screening tools]

Emergency department (ED) admissions of patients 75 years and older are consistently increasing. Older patients suffer from atypical symptomatology, spend more time, and are more at risk of adverse outcomes (early readmission, functional decline, institutionalization and death) than younger people. The identification of geriatric syndromes like cognitive decline can improve the management of such patients and decrease the rate of the outcomes. In ED, screening tools developed to detect these geriatric problems have to be quick, easy to use and to present a high sensibility. This article aims at reviewing the literature about the ED-validated screening tools that could be applied in practice.

[Identification of patients at risk for adverse outcomes in emergency department: which screening tools?]

Taking care of elderly patients is difficult in emergency settings. Such patients are at risk of becoming non autonomous or to be rehospitalized. An individualized evaluation makes it possible to decrease this risk but is time consuming, which represents a problem when it is crucial to maintain the flux of patients. Several tools allowing the tracking down of patients at risk have been developed with the aim to identify those who are likely to benefit from a management and those who could, on the opposite, be discharged without performing investigations. The aim of this review is to depict the different tools available to track down patients at risk and to evaluate their efficacy and usefulness in an emergency setting.

Identification of older patients at risk of unplanned readmission after discharge from the emergency department

STUDY HYPOTHESIS: The Identification of Senior At Risk (ISAR) and the Triage Risk Stratification Tool (TRST) are the two most studied screening tools to detect high-risk patients for unplanned readmission after an emergency department (ED)-visit. Since their performance was unclear among ED-patients over 75 years, we evaluated their capacities to predict readmission at 1, 3, 6 and 12 months as well as their usefulness in avoiding unnecessary further comprehensive geriatric assessment (CGA) in negative screened patients. METHODS: Historical cohort study with systematic routine data collection of functional status, comorbid conditions and readmission rate of patients released home after an ED-visit between 2007 and 2009 at the Geneva University Hospitals. RESULTS: 345 patients were included (mean age 84y; 63% female). Readmission rates were 25%, 38%, 49%, and 60% at 1, 3, 6, and 12 months, respectively. Positive ISAR (≥2/6) and TRST (≥2/5) predicted modestly unplanned readmission at each time point (AUC range: 0.607–0.664). Prediction of readmission with ISAR or TRST was not modified after adjustment for variables significantly associated with readmission (being male, having poor functional or comorbid scores). In case of negative ISAR or TRST, their high negative predictive values (NPV) would safely allow avoiding 64 useless CGA (ISAR <2: 7/64 readmissions at 1 month). CONCLUSIONS: Both ISAR and TRST tools predicted modestly unplanned readmission after an ED-visit among patients over 75 years. Nevertheless, due to their low specificity and high NPV these screening tools are useful to select elderly ED-patients who can safely return home without any further CGA.

Fractures during childhood and adolescence in healthy boys: relation with bone mass, microstructure, and strength

CONTEXT

In healthy boys, fractures result from trauma of various severity, suggesting contribution of an intrinsic biomechanical fragility.

OBJECTIVES

Our objective was to characterize bone mineral mass, microstructure, and strength in boys with and without fractures.

PARTICIPANTS AND DESIGN

We followed 176 healthy boys from 7.4 ± 0.5 to 15.2 ± 0.5 (mean ± sd) yr of age.

OUTCOMES

Areal (a) bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry at radius metaphysis and diaphysis, total hip, femoral neck and diaphysis, and L2-L4 vertebrae. Volumetric (v) BMD and microstructure were assessed by high-resolution peripheral computerized tomography at both distal tibia and radius. Bone strength was evaluated by micro-finite element analysis.

RESULTS

A total of 156 fractures were recorded in 87 of 176 boys with peak incidence between 10 and 13 yr. At 7.4 yr, subjects with fractures had lower aBMD in all sites and at 15.2 yr in femoral and spinal, but not in radius, sites. At that age, boys with fractures displayed lower trabecular (Tb) vBMD (P = 0.029) and number (P = 0.040), stiffness (P = 0.024), and failure load (P = 0.016) at distal tibia, but not distal radius. Odds ratios of fracture risk per 1 sd decrease were 1.80 (P = 0.006) for femoral neck aBMD and 1.46 (P = 0.038) for distal tibia Tb vBMD, 1.59 (P = 0.031) for Tb number, 1.53 (P = 0.072) for stiffness, and 1.60 (P = 0.056) for failure load.

CONCLUSION

In a homogeneous cohort of healthy boys, fractures recorded until 15.2 ± 05 yr of age were associated with lower femoral neck aBMD and with lower distal tibia trabecular vBMD and number, stiffness and failure load. These deficits in bone mineral mass, microstructure and strength could contribute to the occurrence of fractures during growth.

Pubertal timing and body mass index gain from birth to maturity in relation with femoral neck BMD and distal tibia microstructure in healthy female subjects

Childhood body mass index (BMI) gain is linked to hip fracture risk in elderly. In healthy girls, menarcheal age is inversely related to BMI gain during childhood and to femoral neck areal bone mass density (aBMD) and distal tibia structural components at maturity. This study underscores the importance of pubertal timing in age-related fragility fracture risk.

INTRODUCTION

Recent data point to a relationship between BMI change during childhood and hip fracture risk in later life. We hypothesized that BMI development is linked to variation in pubertal timing as assessed by menarcheal age (MENA) which in turn, is related to peak bone mass (PBM) and hip fracture risk in elderly.

METHODS

We studied in a 124 healthy female cohort the relationship between MENA and BMI from birth to maturity, and DXA-measured femoral neck (FN) aBMD at 20.4 year. At this age, we also measured bone strength related microstructure components of distal tibia by HR-pQCT.

RESULTS

At 20.4 ± 0.6 year, FN aBMD (mg/cm(2)), cortical thickness (μm), and trabecular density (mg HA/cm(3)) of distal tibia were inversely related to MENA (P = 0.023, 0.015, and 0.041, respectively) and positively to BMI changes from 1.0 to 12.4 years (P = 0.031, 0.089, 0.016, respectively). Significant inverse (P < 0.022 to <0.001) correlations (R = -0.21 to -0.42) were found between MENA and BMI from 7.9 to 20.4 years, but neither at birth nor at 1.0 year. Linear regression indicated that MENA Z-score was inversely related to BMI changes not only from 1.0 to 12.4 years (R = -0.35, P = 0.001), but also from 1.0 to 8.9 years, (R = -0.24, P = 0.017), i.e., before pubertal maturation.

CONCLUSION

BMI gain during childhood is associated with pubertal timing, which in turn, is correlated with several bone traits measured at PBM including FN aBMD, cortical thickness, and volumetric trabecular density of distal tibia. These data complement the reported relationship between childhood BMI gain and hip fracture risk in later life.

Socioeconomic and living conditions are determinants of hip fracture incidence and age occurrence among community-dwelling elderly

In this prospective, 10-year study in community-dwelling elderly aged 50 years and over, hip fracture incidence and accordingly age at hip fracture were inversely associated with the area-level income, independently of the geographical area. Age at hip fracture also depended of marital status but in a gender-specific way.

PURPOSE

The purpose of this study is to investigate the impact of socioeconomic and living conditions on hip fracture incidence and age occurrence among community-dwelling elderly.

METHOD

Between January 1991 and December 2000, 2,454 hip fractures were recorded in community-dwelling adults aged 50 years and over in the Geneva University Hospital, State of Geneva, Switzerland. Median annual household income by postal code of residence (referred to as area-level income) based on the 1990 Census was used as a measure of socioeconomic condition and was stratified into tertiles (< 53,170; 53,170-58,678; and ≥ 58,678 CHF). Hip fracture incidence and age occurrence were calculated according to area-level income categories and adjusted for confounding factors among community-dwelling elderly.

RESULTS

Independently of the geographical area (urban versus rural), community-dwelling persons residing in areas with the medium income category presented a lower hip fracture incidence [OR 0.91 (0.82-0.99), p = 0.049] compared to those from the lowest income category. Those in the highest income category had a hip fracture at a significant older age [+1.58 (0.55-2.61) year, p = 0.003] as compared to those in the lowest income category. Age at hip fracture also depended on marital status but in a gender-specific way, with married women fracturing earlier.

CONCLUSIONS

These results indicate that incidence and age occurrence of hip fracture are influenced by area-level income and living conditions among community-dwelling elderly. Prevention programs may be encouraged in priority in communities with low income.

The influence of pubertal timing on bone mass acquisition: a predetermined trajectory detectable five years before menarche

BACKGROUND

Later menarcheal age (MENA) is a risk factor for osteoporosis. It is associated with low peak bone mass (PBM). Like PBM, MENA is under strong genetic influence. We hypothesized that MENA-related bone mass differences could be predetermined before puberty.

METHODS

We tested this hypothesis in 124 healthy subjects followed from age 7.9 to 20.4 yr with dual-energy x-ray absorptiometry assessment at mean ages of 8.9, 10.0, 12.4, and 16.4 yr. Six sites were measured: radial metaphysis, radial diaphysis, femoral neck, trochanter, femoral diaphysis, and L2-L4. Mean MENA (+/-SD) was 13.0 +/- 1.2 yr. The cohort was segregated by the median of MENA into LATER (14.0 +/- 0.7 yr) and EARLIER (12.1 +/- 0.7 yr) subgroups.

RESULTS

At 20.4 +/- 0.6 yr, areal bone mineral density (aBMD) was lower in the LATER than the EARLIER subgroup at all six sites, with a mean difference of -0.31 Z-score (P = 0.022). Lower Z-scores in the LATER than in the EARLIER subgroup were observed at all sites at mean ages of 10.0, 12.4, and 16.4 yr, and before pubertal maturation, i.e. at 8.9 yr with a mean Z-score difference of -0.34 (P = 0.016). From mean age 8.9 to 20.4 yr, aBMD gains of all sites were similar in LATER and EARLIER subgroups, with mean of +301 and +308 mg/cm(2) (P = 0.402), respectively.

CONCLUSIONS

In prepubertal girls who will experience later menarche, a deficit in aBMD can already be observed before the onset of pubertal maturation, with no further accumulated deficit until PBM compared to girls with earlier menarche. This suggests that shorter estrogen exposure from prepuberty to PBM is not the main factor for increased osteoporosis risk associated with later menarche. Rather common genetic determinants of low bone mass and later puberty could be involved.

Reversal of the hip fracture secular trend is related to a decrease in the incidence in institution-dwelling elderly women

In this prospective 10-year study in elderly aged 60 years and over, there was a 1.3% per year reduction in the standardized incidence of hip fracture in women but not in men. This decrease was mainly due to changes in the standardized incidence of hip fracture in institution-dwelling women.

INTRODUCTION

A decrease in age-adjusted hip fracture incidence has been recently demonstrated in some countries. Since a large proportion of hip fractures occur in nursing homes, we analyzed whether this decreasing trend would be more detectable in institution-dwelling elderly compared with community-dwelling elderly.

METHODS

All hip fracture patients aged 60 years and over were identified in a well-defined area. Incidence of hip fracture, age- and sex-adjusted to the 2000 Geneva population, was computed in community- and institution-dwelling elderly.

RESULTS

From 1991 to 2000, 1,624 (41%) hip fractures were recorded in institutionalized-dwelling elderly and 2,327 (59%) in community-dwelling elderly. The standardized fracture incidence decreased by 1.3% per year in women (p = 0.039), but remained unchanged in men (+0.5%; p = 0.686). Among institution-dwelling women, hip fracture incidence fell by 1.9% per year (p = 0.044), whereas it remained stable among community-dwelling women (+0.0%, p = 0.978). In men, no significant change in hip fracture incidence occurred among institution- or community-dwelling elderly.

CONCLUSIONS

The decrease in the standardized hip fracture incidence in institution-dwelling women is responsible for the reversal in secular trend. Future research should include stratification according to the residential status to better identify the causes responsible for the trend in hip fracture incidence.

Incidence of hip fracture over a 10-year period (1991-2000): reversal of a secular trend

INTRODUCTION

Hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, disability, and costs. With the ageing of the population, a marked increase in the number of fractures is expected. Furthermore, many studies reveal an increase of the age-adjusted hip fracture incidence. We specifically examined secular changes in the incidence of hip fracture in women and men aged 50 years and over in the well-defined area of Geneva, Switzerland.

MATERIALS AND METHODS

All hip fractured patients were retrospectively identified from the computer medical records of the main hospital, which is receiving 95% of hip fractures occurring in a well-defined area.

RESULTS

From 1991 to 2000, 4115 hip fractures were recorded in 2981 women and 822 men with a mean age (+/-S.D.) of 83.1+/-8.9 and 78.3+/-11.6 years, respectively. A second hip fracture occurred in 276 women (9.3%) and 36 men (4.4%), on average 2.1+/-1.9 (median 1.44) years after the first event without gender difference. The overall incidence of hip fractures was 455 (95% CI: 439-471) per 100,000 person-years in women and 153 (95% CI: 143-163) in men. The number of hip fractures remained constant (412 (95% CI: 397-426)), but the mean age of these patients increased each year by 0.13 year in women (p=0.019) and by 0.04 year in men (NS). Furthermore, the age-adjusted incidence of hip fractures, standardized to the 2000 Geneva population, decreased significantly by 1.4% (95% CI: -2.6 to -0.1) per year in women (p=0.021), but remained stable in men (0.5% (95% CI: -1.7 to +2.8) per year, p=0.66). The overall female/male ratio of hip fracture incidence was 2.99 (95% CI: 2.80-3.18, p<0.001) and significantly decreased by 0.07 (95% CI: -0.13 to -0.01) per year (p=0.024).

CONCLUSION

Despite an increase in the population at risk and in the mean age of hip fractured women, there was a significant decrease in age-adjusted incidence in women but not in men. These results may suggest a reversal of the previously observed secular trend.

Skeletal site selectivity in the effects of calcium supplementation on areal bone mineral density gain: a randomized, double-blind, placebo-controlled trial in prepubertal boys

BACKGROUND

Calcium supplementation during childhood and adolescence is considered an early means of preventing osteoporosis in adults. Prepuberty is an opportune time for detecting the benefits of calcium in girls.

OBJECTIVE

The objective was to assess whether calcium supplementation increases bone mass gain in prepubertal boys in a skeletal site-specific manner.

METHODS

In a 12-month double-blind, placebo-controlled trial with 1-yr follow-up, 235 healthy prepubertal boys aged 7.4 +/- 0.4 yr (mean +/- sd) were randomized to receive two food products providing 850 mg/d calcium (calcium supplement group, n = 116) or an isocaloric placebo (n = 119). Areal bone mineral density (aBMD) was determined by dual-energy x-ray absorptiometry at radius (two sites), hip (two sites), femoral diaphysis (FDia), and L2-L4 vertebrae.

RESULTS

At 12 months, aBMD gain was greater at the FDia and at the mean of the five appendicular skeletal sites in the calcium supplement group in both intention-to-treat analysis [76 +/- 32 vs. 64 +/- 33 mg/cm(2).yr; difference, 12.0 (95% confidence interval, CI, 3.6-20.3), P = 0.006; and 33 +/- 16 vs. 28 +/- 16 mg/cm(2).yr; difference, 5.1 (95% CI, 0.9-9.2); P = 0.018, respectively] and active treatment analysis [81 +/- 32 vs. 64 +/- 31 mg/cm(2).yr; difference, 17.2 (95% CI, 7.9-26.5); n = 174, P < 0.001; and 35 +/- 16 vs. 28 +/- 14 mg/cm(2).yr; difference, 7.5 (95% CI, 2.9-12.2); P = 0.002]. There was no beneficial effect of calcium on lumbar spine. The calcium effect was still detectable by ANOVA repeated measures analysis at the FDia (P = 0.004) and at the mean of the five appendicular skeletal sites (P = 0.002) 1 yr after the end of intervention (active treatment analysis). There was no change in bone size.

CONCLUSION

In prepubertal boys, calcium-enriched foods increased aBMD at several appendicular skeleton sites, but not at the lumbar spine, and this without any bone size change. This effect was maintained 1 yr after treatment discontinuation.

Protein intake and bone growth

Among osteotrophic nutrients, proteins play an important role in bone development, thereby influencing peak bone mass. Consequently, protein malnutrition during development can increase the risk of osteoporosis and of fragility fracture later in life. Both animal and human studies indicate that low protein intake can be detrimental for both the acquisition of bone mass during growth and its conservation during adulthood. Low protein intake impairs both the production and action of IGF-I (Insulin-like growth factor-I). IGF-I is an essential factor for bone longitudinal growth, as it stimulates proliferation and differentiation of chondrocytes in the epiphyseal plate, and also for bone formation. It can be considered as a key factor in the adjustments of calcium-phosphate metabolism required for normal skeletal development and bone mineralization during growth. In healthy children and adolescents, a positive association between the amount of ingested proteins and bone mass gain was observed in both sexes at the level of the lumbar spine, the proximal femur and the midfemoral shaft. This association appears to be particularly significant in prepubertal children. This suggests that, like for the bone response to either the intake of calcium or weight-bearing exercise, the skeleton would be particularly responsive to the protein intake during the years preceding the onset of pubertal maturation.

Evaluation of the age-adjusted incidence of hip fractures between urban and rural areas: the difference is not related to the prevalence of institutions for the elderly

As many as 40% of hip fractures occur in institutions for the elderly. Several studies have demonstrated a higher age-adjusted incidence of hip fractures in urban areas compared with rural areas. To assess whether this difference could be due to a preferential location of institutions for the elderly in urban areas, we compared the incidence of hip fractures over a 5-year period in urban versus rural areas, as defined according to the population density (urban > 15 inhabitants/ha2). We then determined the age-adjusted incidence of hip fractures in institutional-dwelling elderly and home-dwelling elderly. Hip fracture incidence was 100.0/100,000 (150.5 in women and 43.8 in men) in urban areas, and 71.0/100,000 (107.2 in women and 32.8 in men) in rural areas (p<0.001). When only those patients living in their own homes were analyzed, the incidence was 66.7/100000 (94.6 in women and 35.7 in men) in urban regions and 36.8/100,000 (49.6 in women and 23.4 in men) in rural areas (p<0.001), a difference of even greater magnitude than when both home-dwelling and institutional-dwelling residents were considered together. In a logistic regression model including age class, gender, urban or rural areas and institutionalization for inhabitants 65 years of age and older, urban residents have a 31% significantly (p<0.001) higher incidence of hip fracture compared with rural residents; women have a 79% significantly (p<0.001) higher incidence of hip fracture compared with men; and institutional-dwelling elderly have a 351% significantly (p<0.001) higher incidence of hip fracture compared with home-dwelling elderly. These results confirm the existence of a higher age-adjusted incidence of hip fractures in urban compared with rural areas. Since this difference is increased when patients living at home were analyzed separately, it indicates that the difference between urban and rural areas is not due to a preferential urban location of institutions for the elderly.

An osteoporosis clinical pathway for the medical management of patients with low-trauma fracture

Patients with an osteoporotic fracture have at least a 2-fold risk for additional fracture and should benefit from targeted diagnostic and treatment procedures for osteoporosis. To address this issue, we set up an osteoporosis clinical pathway (OCP) for the medical management of patients with low-trauma fracture. Following acute management of the fracture by the orthopedic team, patients are enrolled in the pathway, which is based on an interaction between the OCP multidisciplinary team, orthopedic surgeons and/or primary care physicians. After collection of patient data, suggestions for additional diagnostic examinations with their interpretation, and treatment proposals are made. Patients and their families are also invited to attend a multidisciplinary interactive educational program on physical therapy, lifestyle habits and nutrition. During a 36-month period, 385 patients (311 women, 74 men; mean age +/- SD: 73.0 +/- 13.5 years; hip fracture 45%, ankle/tibia 24%, proximal humerus 8.6%, spine 5.5%, pelvis 3.9%, distal forearm 3.6%, other sites 17.4%) were enrolled in the OCP. An osteoporosis awareness questionnaire administered within 10 days of fracture showed that 73% of patients believed that their fracture was not related to the disease. Dual-energy X-ray absorptiometry, performed in 63% of patients, showed that 86% had low bone mass or osteoporosis. Specific antiosteoporotic therapy was proposed for 33% of patients in addition to calcium and vitamin D supplements, the latter suggested for 93%. A survey performed in 216 patients 6 months later, indicated that 63% of the suggested treatments had been prescribed and that 67% of this group were continuing treatment. Such a clinical pathway for the medical management of low-trauma fracture can help to identify patients with osteoporosis in a high-risk population, provide support to the orthopedic surgeon and/or the primary care physician for diagnostic and treatment procedures, and should significantly contribute to increase awareness of the disease in patients and their families.

Gain in bone mineral mass in prepubertal girls 3.5 years after discontinuation of calcium supplementation: a follow-up study

BACKGROUND

Calcium supplementation during childhood and adolescence increases bone-mass accrual. Whether or not this benefit persists after discontinuation of supplementation is not known. We previously showed a favourable effect of milk-extracted calcium phosphate incorporated in various foods on accumulation of bone mineral mass in 8-year-old girls. We now report the results of a follow-up study undertaken more than 3 years after the end of calcium supplementation.

METHODS

Anthropometric and bone variables were measured in 116 of the 144 girls whose data had been studied at the end of the supplementation period. The mean time elapsed between the end of the intervention period and this follow-up measurement was 3.5 years. Areal bone mineral density was measured by dual-energy X-ray absorptiometry at the same six skeletal sites as those studied during the intervention phase.

FINDINGS

We were able to remeasure 62 and 54 girls of the calcium-supplemented and placebo groups, respectively. The increase from baseline in the overall mean bone mineral density of the six skeletal sites was still highly significant (calcium-supplemented group 179 mg/cm(2) [SE 8] vs placebo group 151 mg/cm(2) [7], p=0.012). A significant difference in favour of the supplemented group was also seen with respect to mean bone mineral content (p=0.031) and mean bone area (p=0.04). Difference in pubertal maturation did not seem to account for the recorded differences.

INTERPRETATION

Our results suggest that this form of milk-extracted calcium phosphate taken during the prepubertal period can modify the trajectory of bone mass growth and cause a long-standing increase in bone mass accrual, which lasts beyond the end of supplementation.

Protein intake and bone disorders in the elderly

Malnutrition, most notably protein deficiency, contributes to the occurrence of osteoporotic fractures not only by decreasing bone mass but also by altering muscle function. Furthermore, malnutrition is associated with increased morbidity in patients with osteoporotic fractures. The somatomedin system (IGF-1) may be directly involved in the pathogenesis of osteoporotic hip fractures and their complications in elderly patients. A low IGF-1 level is a risk factor for hip fracture. In subjects with appropriate intakes of vitamin D and calcium, giving protein supplements to correct an inadequate spontaneous protein intake increases circulating IGF-1 levels, improves clinical outcomes after hip fracture, and prevents bone mineral density loss at the proximal femur. Supplemental protein also significantly reduces the length of inpatient rehabilitation care. These data emphasize the importance of adequate nutrient intake in the prevention and treatment of osteoporotic fractures.

[Bone and hormones. Effects of parathyroid hormone on the bone]

ACTION OF PTH: Parathyroid hormone (PTH) stimulates both bone formation and bone resorption. It also stimulates synthesis of 1,25-dihydroxyvitamin D3 which increases intestinal absorption of calcium and phosphorus and stimulates bone resorption. In bone tissue, PTH acts mainly on osteoblasts which, unlike osteoclasts, carry PTH receptors. PTH also exerts an indirect action on osteoclasts, increasing their number and activity. IMPACT OF INSUFFICIENT PTH: In the absence of PTH, bone remodeling is greatly reduced. Increased bone density has been observed in patients with hypoparathyroidism studied 10 years after total thyroidectomy. IMPACT OF EXCESS PTH: Chronic excess of PTH accelerates bone loss. In primary hyperparathyroidism, reduction of bone density to the order of 10% has been observed, which corresponds to one standard deviation compared with normal subjects of the same age and sex. The hypothesis of an increased risk of fractures remains unresolved. ADMINISTRATION OF PTH: Intermittent rather than continuous subcutaneous administration appears to be necessary to observe the anabolic effects of PTH on bone. The conjunction of favorable anabolic effects demonstrated in animal models, concerning both bone density and mechanical properties, and early studies in humans, provide converging arguments similar to those observed in preclinical investigations, suggest that PTH could be a promising treatment for osteoporosis.

Arginine increases insulin-like growth factor-I production and collagen synthesis in osteoblast-like cells

Protein-energy malnutrition, which is common in elderly patients with osteoporotic hip fractures, is associated with reduced plasma levels of insulin-like growth factor-I (IGF-I). IGF-I is an important regulator of bone metabolism, particularly of osteoblastic bone formation both in vivo and in vitro. Pharmacological doses of arginine (Arg) increase growth hormone (GH) and IGF-I serum levels. Whether amino acids, particularly Arg, can directly modulate the production of IGF-I by osteoblasts is not known. We investigated the effects of increasing concentrations of Arg on IGF-I expression and production, alpha1(I) collagen expression and collagen synthesis, and cell proliferation and cell differentiation, as assessed by alkaline phosphatase (ALP) activity and osteocalcin (OC) release, in confluent mouse osteoblast-like MC3T3-E1 cells. The addition of Arg (7.5-7500 micromol/L, equivalent to 0.1- to 100-fold human plasma concentration) for 48 h increased IGF-I production (adjusted for cell number) in a concentration-dependent manner with a maximum of 2.3 +/- 0.3-fold at 7500 micromol/L Arg [x +/- standard error of the mean (SEM), n = 3 experiments, p < 0.01]. Arg (7.5-7500 micromol/L) increased the percentage of de novo collagen synthesis in a concentration-dependent manner (2.1 +/- 0.4-fold with 7500 micromol/L Arg, p < 0.001) and ALP activity with a maximal stimulation of 144% +/- 13% plateauing at 750 micromol/l Arg (p = 0.002). The steady state level of IGF-I messenger ribonucleic acid (mRNA) and alpha1(I) collagen mRNA (both normalized to cyclophilin mRNA) of cells incubated with Arg at high (100-fold) or low (0.1-fold) human plasma concentrations, was 1.4 +/- 0.2, 1.2 +/- 0.2, and 1.1 +/- 0.2 after 24 h for the 7.5, 1.8, and 0.9 kb IGF-I mRNA transcripts, respectively (n = 3 experiments) and 1.5 +/- 0.2 and 3.1 +/- 0.7 after 24 and 48 h, respectively, for the combined analysis of the 5.6 and 4.7 kb alpha1(I) collagen mRNA transcripts (n = 3 experiments). A maximal mitogenic effect (cell number) of +21% +/- 3% (p < 0.01) was obtained with 1000 micromol/L Arg. In contrast, Arg (7.5-7500 micromol/L) induced a reduction of OC production, which reached 30% +/- 3% with 7500 micromol/L Arg (p = 0.02). In conclusion, Arg stimulated IGF-I production and collagen synthesis in osteoblast-like cells. Thus, Arg may influence bone formation by enhancing local IGF-I production.

Dexamethasone enhances the osteogenic effects of fluoride in human TE85 osteosarcoma cells in vitro

The in vitro osteogenic effects of fluoride have not always been consistently observed in human bone cells. The present study sought to test if dexamethasone (Dex) could potentiate the action of fluoride to increase the detectability of the stimulatory effects of fluoride on [3H]thymidine incorporation, alkaline phosphatase (ALP) specific activity, collagen synthesis, and osteocalcin secretion in human TE85 osteosarcoma cells. Neither Dex at 10(-10)-10(-6) M or fluoride at a mitogenic dose (100 microM) had any consistent stimulatory effects on thymidine incorporation. When the cells were treated with both agents simultaneously, significant and highly reproducible stimulations were observed. The mitogenic effects of the two agents were confirmed with cell number counting. Analysis of variance (ANOVA) revealed a significant interaction (P < 0.001) between fluoride and Dex on cell proliferation. The enhancing effect of Dex on [3H]thymidine incorporation was not due to a shift of the optimal dose response of fluoride. Though fluoride alone or Dex alone also had no consistent effect on ALP specific activity, the co-treatment with fluoride and Dex for 24 hours produced significant (P < 0.001, ANOVA) stimulation in ALP specific activity. Fluoride alone had no consistent effect on collagen synthesis and on 1, 25(OH)2D3-dependent osteocalcin secretion, whereas Dex treatment consistently inhibited these two osteoblastic parameters in a dose-dependent manner. However, both the collagen synthesis and osteocalcin secretion rates were significantly higher (P < 0.001 ANOVA for each) when the cells were co-treated with Dex and fluoride (100 microM) than when they were treated with Dex alone. Thus, these data indicate that the response in collagen synthesis and osteocalcin secretion to fluoride stimulation was more readily observed in the presence of Dex than in its absence. ANOVA analysis revealed that the interaction between fluoride and Dex on collagen synthesis, but not the 1,25(OH)2D3-dependent osteocalcin secretion, was significant (P < 0.02). In summary, we have demonstrated for the first time that in TE85 cells (1) Dex potentiated the effects of fluoride on cell proliferation, ALP specific activity, and collagen synthesis; (2) while Dex at 10(-7)-10(-6) M alone inhibited the collagen synthesis and at 10(-9)-10(-6) M reduced osteocalcin secretion, Dex at 10(-8)-10(-6) M significantly stimulated the proliferation of TE85 cells; and (3) Dex interacted with fluoride to increase the percentage of experiments showing an osteogenic action of fluoride. In conclusion, the in vitro osteogenic actions of fluoride in human TE85 cells are more consistently observed in the presence than in the absence of Dex.

Evidence for a role for insulin-like growth factor binding proteins in glucocorticoid inhibition of normal human osteoblast-like cell proliferation

Glucocorticoids (GCs) inhibit bone formation in vivo and inhibit osteoblast proliferation and collagen synthesis in vitro. These effects may be mediated by alterations in the insulin-like growth factor (IGF) system. In the present study of normal human osteoblast-like (HOB) cells, we tested the hypothesis that dexamethasone (Dex) inhibits IGF anabolic activity in bone by altering expression of IGF binding proteins (IGFBPs), particularly by decreasing expression of IGFBP-5 and IGFBP-3 (which enhance IGF activity) and increasing expression of IGFBP-4 (which inhibits IGF actions). Dexamethasone treatment caused a dose-dependent inhibition of HOB cell proliferation (69 +/- 4% of control at 10(-8) mol/l Dex) in seven separate experiments. Dexamethasone decreased IGFBP-5 mRNA levels to 20-30% of control (10(-8) and 10(-7) mol/l for 24 h). In six of six HOB preparations, 10(-8) mol/l Dex decreased IGFBP-5 mRNA levels (35 +/- 7% of control) and this effect was time dependent. Dexamethasone also decreased IGFBP-3 mRNA levels (74 +/- 9% of control in three HOB preparations). Dexamethasone decreased secretion of 29-31-kD IGFBP-5 and 38-42-kD IGFBP-3 proteins, determined by Western ligand blot and IGFBP-5 immunoblot, and induced a dose-dependent decrease in IGFBP-3 and IGFBP-5 secretion determined by specific radioimmunoassays. The effects of Dex on IGFBP-4 mRNA and on secretion of 25-kD IGFBP-4 levels were inconsistent between different cell preparations. Results suggest that GC inhibition of IGFBP-5 and IGFBP-3 production could decrease IGF activities and contribute to GC inhibition of bone formation.

Vitamin-D-receptor-gene polymorphisms and change in lumbar-spine bone mineral density

Common vitamin-D-receptor (VDR) gene allelic variants predict bone mineral density. We analysed VDR alleles and rate of change of lumbar-spine bone mineral density over 18 months in 72 elderly subjects. 9 BB homozygotes lost bone mineral density but 26 homozygotes for the alternative genotype (bb) did not (mean change -2.3 [SE 1.0] vs 0.9 [0.7]% per year, p < 0.05), irrespective of calcium intake. Among 37 heterozygotes (Bb), however, change in bone mineral density correlated with calcium intake (r = 0.35, p < 0.03). This association between a genetic marker and rate of bone loss in the elderly suggests that the effect of calcium intake on maintenance of bone mass could relate to VDR gene polymorphisms.

Sodium monofluorophosphate increases vertebral bone mineral density in patients with corticosteroid-induced osteoporosis

Corticosteroid-induced osteoporosis, which particularly affects the axial skeleton and the proximal femur, is characterized by a state of low bone remodelling. Fluoride is a potent stimulator of trabecular bone formation which could potentially be useful in the treatment of corticosteroid-induced osteoporosis. We investigated the effects of sodium monofluorophosphate (26 mg/day of fluoride) combined with 1000 mg of calcium (MFP-calcium-treated group), or of calcium alone (control), given for 18 months, on bone mineral density (BMD) of lumbar spine (LS), femoral neck (FN) and midfemoral shaft (FS) in 48 patients with corticosteroid-induced osteoporosis. Mean ages were 49.4 +/- 3.1 and 51.6 +/- 3.0 years (mean +/- SEM), duration of corticosteroid therapy 7.5 +/- 1.8 and 9.3 +/- 1.7 years, and mean daily dose of prednisone 18.2 +/- 2.3 and 12.1 +/- 1.1 mg in the MFP-calcium-treated group and controls, respectively. Initial BMDs (expressed as the Z-score, i.e. the difference in standard deviations from age- and sex-matched normal subjects) were -1.5 +/- 0.2 and -1.2 +/- 0.2 for LS, -1.4 +/- 0.2 and -1.3 +/- 0.2 for FN, and -0.8 +/- 0.3 and -0.6 +/- 0.3 for FS, in the MFP-calcium-treated group and controls, respectively. Analysis by linear regression of 6-monthly measurement values revealed BMD changes of +7.8 +/- 2.2 versus +3.6 +/- 1.3% (p < 0.02) for LS, -1.5 +/- 1.8 versus +0.9 +/- 1.8% for FN, and -1.1 +/- 1.1 versus -0.5 +/- 1.4% for FS after 18 months of follow-up in the MFP-calcium-treated group and controls, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of tumor necrosis factor-alpha on the expression of insulin-like growth factor I and insulin-like growth factor binding protein 4 in mouse osteoblasts

Tumor necrosis factor-alpha (TNF-alpha) is a cytokine produced by immune cells, which has multiple effects on bone cells and is therefore thought to mediate changes in bone metabolism occurring during inflammation. In the present study we have investigated the effect of TNF-alpha on the secretion of insulin-like growth factor I (IGF-I) and IGF binding protein 4 (IGFBP-4) by clonal mouse osteoblasts (MC3T3-E1 cells) using subconfluent in vitro cultures and serum-free conditions. The IGF-I was determined by radioimmunoassay under conditions eliminating the interference of IGFBPs. Treatment of MC3T3-E1 cultures with TNF-alpha for 24 h resulted in a dose-dependent decrease in IGF-I secretion (maximally to 34 +/- 9.7% of control with 60 pmol/l TNF-alpha; mean +/- SD). The TNF-alpha treatment also resulted in decreased messenger ribonucleic acid (mRNA) levels of IGF-I at 4 and 24 h, as detected by Northern analysis. Because basal secretion of IGFBPs is very low in MC3T3-E1 cells, effects of TNF-alpha on IGFBP secretion were studied in cultures in which IGFBP-4 expression was increased by calcitriol (1,25(OH)2D3) treatment. The presence of TNF-alpha (600 pmol/l) inhibited this calcitriol-induced stimulation of IGFBP-4 mRNA levels from 4 h onwards, with complete inhibition of the calcitriol effect occurring at 24 h. We also observed a dose-dependent inhibition of calcitriol-stimulated IGFBP-4 secretion into the culture medium (as detected by Western ligand blot), with the maximal inhibition occurring with 600 pmol/l TFN-alpha to 25 +/- 7% of control levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of calcium supplements on femoral bone mineral density and vertebral fracture rate in vitamin-D-replete elderly patients

The efficacy of calcium (Ca) in reducing bone loss is debated. In a randomized placebo-controlled double-masked study, we investigated the effects of oral Ca supplements on femoral shaft (FS), femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD), and on the incidence of vertebral fracture in vitamin-D-replete elderly. Ninety-three healthy subjects (72.1 +/- 0.6 years) were randomly allocated to three groups receiving 800 mg/day Ca in two different forms or a placebo for 18 months. Sixty-three patients (78.4 +/- 1.0 years) with a recent hip fracture were allocated to two groups receiving the two forms of Ca without placebo. FS BMD changes in Ca-supplemented non-fractured women were significantly different from those in the placebo group (+0.6 +/- 0.5% v -1.2 +/- 0.7%, p < 0.05). There was no difference in effect between the two forms of Ca. The changes of +0.7 +/- 0.8% v -1.7 +/- 1.6% in FN BMD of Ca-supplemented women and the placebo group did not reach statistical significance. In fractured patients, FS, FN and LS BMD changes were -1.3 +/- 0.8, +0.3 +/- 1.6 and +3.1 +/- 1.2% (p < 0.05 for the last). The rate of new vertebral fractures was 74.3 and 106.2 fractures per 1000 patient-years in Ca-supplemented non-fractured subjects and in the placebo group, respectively, and 144.0 in Ca-supplemented fractured patients. Thus, oral Ca supplements prevented a femoral BMD decrease and lowered vertebral fracture rate in the elderly.

Preferential low bone mineral density of the femoral neck in patients with a recent fracture of the proximal femur

Bone mass is an important determinant of resistance to fractures. Whether bone mineral density (BMD) in subjects with a fracture of the proximal femur (hip fracture) is different from that of age-matched controls is still debated. We measured BMD of the femoral neck (FN) on the opposite side to the fracture, as well as femoral shaft (FS) and lumbar spine (LS) BMD by dual-photon absorptiometry in 68 patients (57 women and 11 men, mean age 78.8 +/- 1.0) 12.4 +/- 0.8 days after hip fracture following a moderate trauma. These values were compared with BMD of 93 non-fractured elderly control subjects (82 women and 11 men), measured during the same period. As compared with the controls, FN BMD was significantly lower in fractured women (0.592 +/- 0.013 v. 0.728 +/- 0.014 g/cm2, P less than 0.001) and in fractured men (0.697 +/- 0.029 v. 0.840 +/- 0.052, P less than 0.05). Expressed as standard deviations above or below the mean BMD of age and sex-matched normal subjects (Z-score), the difference in FN BMD between fractured women and controls was highly significant (-0.6 +/- 0.1 v. +0.1 +/- 0.1, P less than 0.001). As compared with mean BMD of young normal subjects, BMD was decreased by 36.9 +/- 1.4 and 22.4 +/- 1.5% (P less than 0.001) in fractured and control women, respectively. There was no significant difference between FN BMD of 33 women with cervical and 24 with trochanteric hip fractures (0.603 +/- 0.017 v. 0.577 +/- 0.020). FN BMD was lower than 0.705 g/cm2 in 90% of fractured women.(ABSTRACT TRUNCATED AT 250 WORDS)