Diminished bone strength is observed in adult women and men who sustained a mild trauma distal forearm fracture during childhood

Hormonal Control of Bone Architecture Throughout the Lifespan: Implications for Fracture Prediction and Prevention

BACKGROUND

Skeletal modeling in childhood and adolescence and continuous remodeling throughout the lifespan are designed to adapt to a changing environment and resist external forces and fractures. The flux of sex steroids in men and women, beginning from fetal development and evolving through infancy, childhood, puberty, young adulthood, peri/menopause transition, and postmenopause, is critical for bone size, peak bone mass, and fracture resistance.

OBJECTIVE

This review will highlight how changes in sex steroids throughout the lifespan affect bone cells and the consequence of these changes on bone architecture and strength.

METHODS

Literature review and discussion.

RESULTS

The contributions of estrogen and testosterone on skeletal development have been difficult to study due to the reciprocal and intertwining contributions of one on the other. Although orchiectomy in men renders circulating testosterone absent, circulating estrogen also declines due to testosterone being the substrate for estradiol. The discovery of men with absent estradiol or resistance to estrogen and the study of mouse models led to the understanding that estrogen has a larger direct role in skeletal development and maintenance in men and women. The mechanistic reason for larger bone size in men is incompletely understood but related to indirect effects of testosterone on the skeleton, such as higher muscle mass leading to larger mechanical loading. Declines in sex steroids during menopause in women and androgen deprivation therapies in men have profound and negative effects on the skeleton. Therapies to prevent such bone loss are available, but how such therapies can be tailored based on bone size and architecture remains an area of investigation.

CONCLUSION

In this review, the elegant interplay and contribution of sex steroids on bone architecture in men and women throughout the lifespan is described.

Is repeated childhood fracture related to areal bone density or body composition in middle age?

Childhood fracture is common, but whether it predicts adult fracture is not clear. Repeat childhood fracture was associated with adult (≤ 45 years) fracture, and in women, lower areal bone density was associated with repeat childhood fracture. Identifying fracture-prone children can modify adult fracture risk management.

INTRODUCTION

A quarter of boys and 15% of girls will suffer multiple fractures, but it is not clear whether multiple fractures during growth predict fracture risk and areal bone density in adulthood. This study evaluated whether children who repeatedly fracture were at increased risk of low areal bone density, abnormal body composition, and fractures by age 45.

METHODS

A subsample of a large birth cohort study with childhood fracture cases had areal bone density assessed at age 45 years. Participants were questioned regularly across their lifetime about fractures during childhood (ages 0-18 years of age) and adulthood (any fracture between 18 and 45 years). The number of fractures was collapsed into three categories: no fractures; 1 fracture; and > 1 fracture, separately for child and adult groups.

RESULTS

At age 45 years, areal bone mineral density (g/cm2) and body composition were measured with dual X-ray absorptiometry in n = 555 participants. Compared to no fractures, twice as many girls (14% vs 7%, P = 0.156) and boys (31.4% vs 14.1%, P = 0.004) who repeatedly fractured in childhood sustained multiple fractures as adults. Both girls and boys who were fracture-free tended to remain fracture-free as adults (79.8% compared with 62.8%, P = 0.045, and 64.8% compared with 51.4%, P = 0.025, in males and females, respectively). Participants were more than twice as likely to fracture repeatedly as adults if they had sustained multiple fractures as a child (OR 2.5 95% CI: 1.4, 4.6). Women who repeatedly fractured during childhood had lower areal bone density, whereas repeated fracturing during childhood was not associated with areal bone density or body composition in men, even after adjustment for other factors known to influence fracture history.

CONCLUSION

Childhood fracture history is associated with persistent skeletal fragility in adulthood (≤ 45 years), even after adjustment for behavioral and demographic factors known to influence fracture history.

HR-pQCT imaging in children, adolescents and young adults: Systematic review and subgroup meta-analysis of normative data

We aimed to investigate the methodologies on image acquisition of normative data of high-resolution peripheral quantitative computed tomography (HR-pQCT) in children, adolescents and/or young adults (up to 25 years) and to determine their normative data based on available literature. A literature search was conducted in MEDLINE, EMBASE and Web of Science from 1947 to July 2019. Quality of articles was assessed using Standards for Reporting of Diagnostic Accuracy (STARD) scoring system and Modified Newcastle-Ottawa scale (NOS). Articles which fitted the following criteria were combined to meta-analysis: age range (15 to 22.6 years), references at tibia (22.5mm) and/or radius (9.0 to 9.5mm). Eight articles were ultimately included in the systematic review and 4 of them that filled the criteria were summarised in meta-analysis. The results of random effects model of HR-pQCT parameters of the 4 articles were as follows: 1)Radius: bone volume fraction (BT/BV) [estimate 0.17:0.1229(lower)-0.2115 (upper); trabecular number (Tb_N):2.08(2.03–2.12); trabecular thickness (Tb.Th):0.07 (0.07–0.0.08); trabecular separation (Tb.Sp):0.41 (0.38–0.42); cortical thickness (Ct.Th):0.85 (0.76–0.94); cortical porosity (Ct.Po):1.53 (0.63–2.44); total area (Tt.Ar):263.66(-385.3–912.6); total bone density (Tt-vBMD):280.5 (73.1–487.7); Trabecular density (Tb-vBMD):223.6 (47.1–400.09), and cortical density (CT.vBMD):765.9 (389.1–1142.8). 2)Tibia: BT/BV:0.18 (0.17–0.19); Tb_N:2.02 (1.83–2.2); Tb.Th:0.08 (0.80–0.09); Tb.Sp:0.40(0.36–0.44); Ct.Th:1.32(1.26–1.38); Ct.Po:3.15 (1.1–5.2); Tt.Ar:693.1(150.2–1235.8); Tt-vBMD:343.76 (335.5–352.1); Tb-vBMD:223.6 (213.37 (193.5–233.2), and CT.vBMD:894.3 (857.6–931.1). There is overall ‘fair’ evidence on reporting of results of normative data of HR-pQCT parameters in children, adolescents and/or young adults. However, data are scarce pointing out to the urgent need for standardization of acquisition parameters and guidelines on the use of HR-PQCT in these populations.

Pediatric Distal Forearm Fracture Epidemiology in Malmö, Sweden-Time Trends During Six Decades

Background  The distal forearm fracture is the most common fracture in children. To allocate health care resources and evaluate if prevention strategies have been successful, it is essential to monitor changes in the epidemiology of common fractures. Methods  Our hospital serves a city in which year 2006 included 276,244 inhabitants (49,664 <17 years of age). Through the hospital archives, we identified fractures sustained by individuals younger than 16 years during 2005 and 2006 and compared these with previous collected and published data from the same area and hospital for the period 1950 to 1994. We used official population data to estimate period-specific fracture rates and age and gender standardized time trends. We report rates as number of fractures per 100,000 person-years and changes between periods as rate ratios (RR) with 95% confidence intervals (CIs). Results  We identified 521 distal forearm fractures, corresponding to a crude fracture incidence of 564/100,000 person-years (boys 719; girls 401). Age-adjusted fracture incidence was 70% higher in boys than in girls (RR 1.7; 95% CI 1.3-2.3). The age- and gender-adjusted hand fracture incidence was 40% higher in 2005-2006 than in 1950/1955 (RR 1.4; 95% CI 1.2 to 1.8) but no higher than 1993-1994 (RR 1.1; 95% CI 0.9-1.3). Fracture etiology of 2005 to 2006 included sports injuries in 41% and traffic accidents in 11% of the cases, while sports injuries explained 37% and traffic accidents 18% in 1950 to 1955. Conclusion  In 2005 to 2006, we found higher rates in boys and higher overall rates compared with the 1950s but no significant differences compared with the rates in 1993 to 1994. Future studies should include patient-specific data to unravel causal factors. Level of evidence  This is a Level III b study.

The Association between First Fractures Sustained during Childhood and Adulthood and Bone Measures in Young Adulthood

OBJECTIVE

To describe the association between fractures sustained at different stages of growth and bone measures in early adulthood.

STUDY DESIGN

Participants (n = 201) in southern Tasmania were at birth at a higher risk of sudden infant death syndrome; they were followed to age 25. Outcomes were areal bone mineral density at the spine, hip, and total body (by dual-energy x-ray absorptiometry) and trabecular and cortical bone measures at the radius and tibia (by high-resolution peripheral quantitative computed tomography). Fractures were self-reported and confirmed by radiographs at 8, 16, and 25 years of age. Multivariable linear regression was used to analyze the association of the occurrence of prepubertal (<9 years of age), pubertal (9-16 years of age), and postpubertal (17-25 years of age) fractures with all bone measures.

RESULTS

Over 25 years, 99 participants had at least 1 fracture. For high-resolution peripheral quantitative computed tomography measures at age 25, prepubertal fractures were negatively associated with cortical and trabecular volumetric bone mineral density and most microarchitecture measures at both the tibia and radius. Prepubertal fractures had a significant association with smaller increase of areal bone mineral density from age 8 to 16 years and at 25 years of age compared with participants with no fractures. Pubertal fractures had no association with any bone measures and postpubertal fractures were only associated with a lower trabecular number at the tibia.

CONCLUSIONS

Prepubertal fractures are negatively associated with areal bone mineral density increases during growth and high-resolution peripheral quantitative computed tomography bone measures in young adulthood. There is little evidence that fractures occurring from age 8 years onward with bone measures in young adulthood, implying that prepubertal fractures may be associated with bone deficits later in life.

Metacarpal Indices and Their Association with Fracture in South African Children and Adolescents

This prospective study assessed whether metacarpal indices predict fracture risk in children and adolescents. Radiogrammetry was performed at the second metacarpal midshaft on annual hand-wrist radiographs of 359 South African (SA) children aged 10-17 years. Bone length, bone width, and medullary width were measured, and the following proxies for bone strength calculated: metacarpal index (MCI), bone mineral density (BMD), section modulus (SM), stress-strain index (SSI), and slenderness index (SLI). Height and weight were measured annually. Self-reported physical activity (PA) and fracture history were obtained at ages 15 years (for the preceding 12 months) and 17 years, respectively. At 17 years, 82 (23%) participants (black, 16%; white, 42%; p < 0.001) reported a previous fracture. None of the bone measures or indices were associated with fracture in black participants. In white females, after adjusting for PA, a 1 standard deviation (SD) greater SLI doubled the fracture risk [odds ratio (OR) 2.08; 95% confidence interval (CI) 1.08, 3.98]. In white males, a 1 SD greater BMD was associated with a 2.62-fold increase in fracture risk (OR 3.62; 95% CI 1.22, 10.75), whilst a 1 SD greater SM (OR 2.29; 95% CI 1.07, 4.89) and SSI (OR 2.23; 95% CI 1.11, 4.47) were associated with a more than twofold increase in fracture risk, after height, and PA adjustment. No single index consistently predicted fracture across the four groups possibly due to ethnic and sex differences in bone geometry, muscle mass, and skeletal loading. Metacarpal radiogrammetry did not reliably predict fracture in SA children.

Association of High-resolution Peripheral Quantitative Computed Tomography (HR-pQCT) bone microarchitectural parameters with previous clinical fracture in older men: The Osteoporotic Fractures in Men (MrOS) study

High-resolution peripheral quantitative computed tomography (HR-pQCT) assesses both volumetric bone mineral density (vBMD) and trabecular and cortical microarchitecture. However, studies of the association of HR-pQCT parameters with fracture history have been small, predominantly limited to postmenopausal women, often performed limited adjustment for potential confounders including for BMD, and infrequently assessed strength or failure measures. We used data from the Osteoporotic Fractures in Men (MrOS) study, a prospective cohort study of community-dwelling men aged ≥65 years, to evaluate the association of distal radius, proximal (diaphyseal) tibia and distal tibia HR-pQCT parameters measured at the Year 14 (Y14) study visit with prior clinical fracture. The primary HR-pQCT exposure variables were finite element analysis estimated failure loads (EFL) for each skeletal site; secondary exposure variables were total vBMD, total bone area, trabecular vBMD, trabecular bone area, trabecular thickness, trabecular number, cortical vBMD, cortical bone area, cortical thickness, and cortical porosity. Clinical fractures were ascertained from questionnaires administered every 4 months between MrOS study baseline and the Y14 visit and centrally adjudicated by masked review of radiographic reports. We used multivariate-adjusted logistic regression to estimate the odds of prior clinical fracture per 1 SD decrement for each Y14 HR-pQCT parameter. Three hundred forty-four (19.2%) of the 1794 men with available HR-pQCT measures had a confirmed clinical fracture between baseline and Y14. After multivariable adjustment, including for total hip areal BMD, decreased HR-pQCT finite element analysis EFL for each site was associated with significantly greater odds of prior confirmed clinical fracture and major osteoporotic fracture. Among other HR-pQCT parameters, decreased cortical area appeared to have the strongest independent association with prior clinical fracture. Future studies should explore associations of HR-pQCT parameters with specific fracture types and risk of incident fractures and the impact of age and sex on these relationships.

Bone Strength in Girls and Boys After a Distal Radius Fracture: A 2-Year HR-pQCT Double Cohort Study

We recently reported impaired bone strength in girls with low- to moderate-energy distal radius fractures (Fx) compared with girls with no history of forearm fractures (Non-Fx). We aimed to determine whether bone strength deficits observed at baseline were still present after 2 years. We assessed bone strength, microarchitecture, and bone mineral density (BMD) of the non-fractured (Fx) and non-dominant (Non-Fx) distal radius (7% site) at baseline, 12, and 24 months using high-resolution pQCT (Scanco Medical, Brüttisellen, Switzerland) in 104 girls (aged 11.0 ± 1.7 years; 47 Fx, 57 Non-Fx) and 157 boys (aged 12.7 ± 1.7 years; 86 Fx, 71 Non-Fx). Bone outcomes included total area (Tt.Ar) and bone mineral density (Tt.BMD), trabecular bone volume ratio (BV/TV), thickness (Tb.Th), separation (Tb.Sp), and number (Tb.N), and cortical BMD (Ct.BMD), thickness (Ct.Th), and porosity (Ct.Po). We used finite element analysis to estimate bone strength (failure load [F.Load]; ultimate stress [U.Stress]; load-to-strength ratio). We used sex-specific mixed-effects models to compare bone outcomes between Fx and Non-Fx over 2 years. In girls, those with fractures had 18% to 24% lower U.Stress and 5% to 9% lower Tt.BMD than Non-Fx at all time points (p < 0.017). In secondary analysis by fracture degree, girls with low-energy (LE) fractures had 19% to 21% lower F.Load, 25% to 47% lower U.Stress, 11% to 14% lower Tt.BMD, and 11% to 15% lower BV/TV than Non-Fx at all time points (p < 0.017). In contrast, boys' bone outcomes were similar between Fx and Non-Fx at all time points. In secondary analysis by fracture degree, boys with LE fractures had 10% lower Tt.BMD and 10% lower Ct.Th compared with Non-Fx at 12 months only. Deficits in distal radius bone strength and trabecular bone microarchitecture appear to track across 2 years after a forearm fracture in girls but not in boys. Longer follow-up is needed to determine whether deficits persist into adulthood in women and how they may influence future risk of fragility fracture. © 2017 American Society for Bone and Mineral Research.

Incidence and predictors of osteoporotic fractures in patients with Barrett's oesophagus: a population-based nested case-control study

BACKGROUND

Proton pump inhibitors (PPI) are inconsistently associated with osteoporotic fractures. Barrett's oesophagus (BO) patients are treated with high PPI doses for prolonged periods, but there are limited data on the incidence of osteoporosis and fractures in this group pf patients.

AIM

To estimate the incidence of (and risk factors for) low bone mass (osteoporosis and/or osteopenia) related fractures in a population-based BO cohort.

METHODS

All subjects with BO and a diagnosis of osteoporosis and fractures were identified using Rochester Epidemiology Project resources. The incidence rates of all and osteoporotic fractures in these subjects were compared to an age- and gender similar population in Olmsted County to determine standardised incidence ratios (SIR). Predictors were assessed using Cox proportional hazards models.

RESULTS

Five hundred and twenty-one patients were included (median [IQR] age 61 [52, 72] years; 398 [76%] men) of whom 113 (21.7%) had fractures, and 46 (8.8%) had osteoporotic fractures. The incidence of all fractures and osteoporotic fractures was comparable to that of an age- and gender-matched population (SIR 1.09; 95% CI 0.92-1.29: SIR 1.05; 95% CI 0.85-1.29). PPI use, dose or duration of use was not associated with osteoporotic fracture risk (HR 0.87; 95% CI 0.12-6.39). Independent risk factors for osteoporotic fractures included older age, female gender and higher co-morbidity index.

CONCLUSIONS

The incidence of osteoporotic fractures was not increased in BO patients compared to the general population. In addition, PPI use was not associated with increased fracture risk regardless of the duration of therapy or dose.

Fracture Prospectively Recorded From Prepuberty to Young Adulthood: Are They Markers of Peak Bone Mass and Strength in Males?

Fractures are common in otherwise healthy children and adolescents. They result from trauma of varying severity. Some reflect a greater skeletal fragility. A long-term implication of these fractures is their potentiality to predict adult bone fragility and increased risk of osteoporosis in later life. Using dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and micro-finite element analysis (μFEA) measurements, we previously found in 124 healthy females, followed from the age of 7.9 to 20.4 years, substantial deficits in both structural and strength components of the radius in the 42 girls who sustained a fracture during skeletal development. The objective of the current study was to assess in healthy males the relationship between fracture during development and expression of bone fragility in adulthood. A cohort of 152 boys was followed from age 7.4 ± 04 (mean ± SD) to 22.6 ± 0.7 years, ie, when peak bone mass is attained. Ninety participants (59.2%) sustained at least one fracture during growth, with highest incidence within the 10- to 13-year age range. Forearm was the most frequent site of fractures. At 7.4 years, several bone DXA-measured variables (areal bone mineral density [aBMD], bone mineral content [BMC]) were lower in the group with a positive fracture history during skeletal development compared with the non-fractured group. In contrast, at 22.6 years, no DXA-measured sites, including forearm, indicated a deficit in the fractured group compared with the non-fractured group. Likewise, at 22.6 years, neither HR-pQCT nor μFEA measurements, including distal radius, showed a structural or strength deficit in the fractured group. These results markedly contrast with a similar prospective study using the same technical and clinical design in 124 healthy girls. In conclusion, our prospective studies suggest a sex difference in the predictability of bone fragility in young adults who sustained fractures during childhood and adolescence. This difference might be related to the degree of trauma severity, usually lower in girls than in boys. © 2017 American Society for Bone and Mineral Research.

Do bone mineral content and density determine fracture in children? A possible threshold for physical activity

BackgroundRelations between bone parameters, physical exertion, and childhood fractures are complex. We aimed to estimate the associations between fracture history and bone mineral content (BMC) and areal bone mineral density (aBMD) at 7 years of age, by levels of physical activity, as a proxy for trauma frequency.MethodsWe used data collected from 2,261 children of the Generation XXI birth cohort, assembled in 2005/6 in Porto, Portugal. At the age of 7 years (2012/4), fracture history, time spent per week in active play, and sports practice were reported by parents. Subtotal and lumbar spine (LS) BMC and aBMD were measured using whole-body dual-energy X-ray absorptiometry.ResultsBoys and girls in the highest categories of time spent in sports practice or active play generally had higher BMC and aBMD. Among girls, BMC and aBMD were protective of fracture only in the highest quarter of active play (>660 min/week)-odds ratios (OR; 95% confidence interval (95% CI)) for subtotal BMC=0.27 (0.11-0.67), subtotal aBMD=0.18 (0.06-0.49), and LS aBMD=0.41 (0.22-0.75). For boys in the highest quarter of sports practice (>240 min/week), subtotal and LS BMC were protective of fracture-OR=0.39 (0.16-0.98) and 0.51 (0.27-0.96), respectively.ConclusionIn prepubertal children, BMC and aBMD predicted fracture history only in the highest levels of physical activity.

Epidemiology and time trends of distal forearm fractures in adults - a study of 11.2 million person-years in Sweden

Background

A distal forearm fracture is a very common injury causing both suffering and substantial health care costs. The incidence of this fracture type seemed to increase worldwide until the middle 1980’s, but thereafter most reports have shown stable or decreasing rates. As few large studies have been presented lately we aimed to describe recent epidemiology and time trends of distal forearm fractures in adults. We paid special attention to fractures in working ages as they present challenges in terms of treatment and costs for sick-leave, and have not previously been thoroughly investigated.

Methods

By use of population data from Statistics Sweden and official in- and out-patient register data of men and women (≥17 years) in Sweden (Skåne region), we ascertained distal forearm fractures and estimated age- and sex-specific rates and time-trends from year 1999 to 2010 (11.2 million person-years (py)).

Results

The total incidence rate was 278 per 100,000 py (31,233 fractures) with 23% higher annual numbers 2010 compared with 1999. An increase in the annual age standardized incidence was found in men, +0.7% per annum (95% confidence interval (CI) 0.1, 1.4), and women, +0.9% (95% CI 0.5, 1.3), driven mainly by an increasing incidence in working ages (17–64 years). Also, expected demographic changes including a 25% population increase may result in 38% more fractures until 2050, compared to 2017.

Conclusions

The incidence of distal forearm fractures in adults in southern Sweden is increasing, mainly driven by an increase in working ages. In combination with expected demographic changes these findings may present substantial challenges for the future.

Bone Densitometry in Children and Adolescents

Concerns about bone health and potential fragility in children and adolescents have led to a high interest in bone densitometry. Pediatric patients with genetic and acquired chronic diseases, immobility, and inadequate nutrition may fail to achieve expected gains in bone size, mass, and strength, leaving them vulnerable to fracture. In older adults, bone densitometry has been shown to predict fracture risk and reflect response to therapy. The role of densitometry in the management of children at risk of bone fragility is less clear. This clinical report summarizes current knowledge about bone densitometry in the pediatric population, including indications for its use, interpretation of results, and risks and costs. The report emphasizes updated consensus statements generated at the 2013 Pediatric Position Development Conference of the International Society of Clinical Densitometry by an international panel of bone experts. Some of these recommendations are evidence-based, whereas others reflect expert opinion, because data are sparse on many topics. The statements from this and other expert panels provide general guidance to the pediatrician, but decisions about ordering and interpreting bone densitometry still require clinical judgment. The interpretation of bone densitometry results in children differs from that in older adults. The terms "osteopenia" and "osteoporosis" based on bone densitometry findings alone should not be used in younger patients; instead, bone mineral content or density that falls >2 SDs below expected is labeled "low for age." Pediatric osteoporosis is defined by the Pediatric Position Development Conference by using 1 of the following criteria: ≥1 vertebral fractures occurring in the absence of local disease or high-energy trauma (without or with densitometry measurements) or low bone density for age and a significant fracture history (defined as ≥2 long bone fractures before 10 years of age or ≥3 long bone fractures before 19 years of age). Ongoing research will help define the indications and best methods for assessing bone strength in children and the clinical factors that contribute to fracture risk. The Pediatric Endocrine Society affirms the educational value of this publication.

Skeletal changes through the lifespan--from growth to senescence

Age-related fragility fractures are an enormous public health problem. Both acquisition of bone mass during growth and bone loss associated with ageing affect fracture risk late in life. The development of high-resolution peripheral quantitative CT (HRpQCT) has enabled in vivo assessment of changes in the microarchitecture of trabecular and cortical bone throughout life. Studies using HRpQCT have demonstrated that the transient increase in distal forearm fractures during adolescent growth is associated with alterations in cortical bone, which include cortical thinning and increased porosity. Children with distal forearm fractures in the setting of mild, but not moderate, trauma also have increased deficits in cortical bone at the distal radius and in bone mass systemically. Moreover, these children transition into young adulthood with reduced peak bone mass. Elderly men, but not elderly women, with a history of childhood forearm fractures have an increased risk of osteoporotic fractures. With ageing, men lose trabecular bone primarily by thinning of trabeculae, whereas the number of trabeculae is reduced in women, which is much more destabilizing from a biomechanical perspective. However, age-related losses of cortical bone and increases in cortical porosity seem to have a much larger role than previously recognized, and increased cortical porosity might characterize patients at increased risk of fragility fractures.

The Child with Multiple Fractures, What Next?

Fractures are common during childhood; however, they can also be the presenting symptom of primary or secondary causes of bone fragility. The challenge is to identify those children who warrant further investigation. In children who present with multiple fractures that are not commonly associated with mild to moderate trauma or whose fracture count is greater than what is typically seen for their age, an initial evaluation, including history, physical examination, biochemistry, and spinal radiography, should be performed. In children with bone pain or evidence of more significant bone fragility, referral for specialist evaluation and consideration of pharmacologic treatment may be warranted.