Decreased bone mass in adolescents with bone fragility fracture but not in young children: a case-control study

Background

The incidence of distal forearm fracture due to minimal/moderate trauma shows a bimodal distribution for age at event, with one peak occurring during early adolescence, in both boys and girls and the other one in postmenopausal females. The aim of this study was, therefore, to document whether the relationship between bone mineral density and fracture is different in young children compared with adolescents.

Methods

A matched-pair, case-control study has been conducted to evaluate bone mineral density in 469 young children and 387 adolescents of both sexes, with/without fracture due to minimal/moderate trauma with assurance that the compared groups were equally susceptible to the outcome event. All fractures were radiographically confirmed. The study utilized bone mineral areal density of the total body, spine, hips, and forearm; volumetric bone mineral density of the forearm; and metacarpal radiogrammetry measurements. The study controlled for skeletal development, bone geometry, body composition, hand grip strength, calcium intake, and vitamin D status.

Results

Adolescents with distal forearm fracture have reduced bone mineral density at multiple skeletal regions of interest. This was documented by the bone mineral areal density measurements at multiple skeletal sites (p < 0.001), volumetric bone mineral density measurements of the forearm (p < 0.0001), and metacarpal radiogrammetry (p < 0.001). Adolescent females with fracture had reduced cross-sectional areas of the radius and metacarpals. The bone status of young female and male children with fracture was no different to its controls. Increased body fatness was more prevalent among fracture cases than in controls. Around 72% of young female and male children with fracture had serum 25-hydroxyvitamin D levels below the threshold of 31 ng/ml, compared with only 42% of female controls and to 51% of male controls.

Conclusions

Adolescents with bone fragility fracture had reduced bone mineral density at multiple skeletal regions of interest, whereas this was not the case with younger children. The results of the study may have implications for the prevention of bone fragility in this segment of the pediatric population.

The European response and transformation towards healthy energy

The EU Green Deal is the framework to achieve carbon neutrality by 2050, and decarbonisation and sustainability in the main economic sectors. This includes a revised greenhouse gas reductions goal of at least 55% for 2030, as well as commitments on zero pollution, healthier agricultural production, sustainable mobility and energy. Moreover, as part of the EU Green Deal, the European Commission has established a Just Transition Mechanism (JTM), to ensure that the transition towards a climate-neutral economy happens in a fair way, leaving no one behind. The aim is to mobilise at least €100 billion over the period 2021-2027 for carbon-intensive industries. But health costs of pollution are absent in Just Transition considerations. The Green Deal includes all the right “buzz words” and commitments for a healthy planet for healthy people. However, policy-makers also need to walk the talk when it comes to adopting the right laws and measures. The science and the acceleration of the climate change, environmental and health crises show us that we need to step up. HEAL believes a zero pollution- and health-based approach can be the overarching principle to deliver on these ambitions. The war in Ukraine as the latest crisis has brought up once again the need for the swift, without any delay, phase-out of all fossil fuels. In Europe, the recently proposed RePower EU plan aims to set a pathway for increased renewables, energy savings and diversification well before 2030. However, with a holistic view of the problem under a health lens, it is clear that in this transition from fossil fuels inequalities and social considerations need to be placed central. Of particular importance is to not give space for false solutions such as replacing Russian imports with fuels from other authoritarian regimes or economies which will only continue to perpetuate Europe's energy dependence, or to build up infrastructure that will continue the pollution (gas and biomass included).

Urban places and Mental Health challenges (lessons learned from Covid-19 crisis)

Nature deprivation under COVID-19 lead to reduced well-being. Urban design interventions were also identified as an important contributor to the restoration of community confidence, choice, and safety. Factors related to sociodemographic, housing and lockdown were linked to changes in exposure to nature during the pandemic lockdown. Changes in exposure to nature and mental health outcomes during the COVID-19 lockdown were strongly linked. Especially young people had an increased number of mental health problems. Children and youth were more bored and worried in comparison with the pre-pandemic period. The educational institutions worldwide were closed or changed to online education during the pandemic, leading to great disturbance in students’ education and outdoor events. All “green infrastructure” (GI) resources (including parks, gardens etc.) received great attention as “essential infrastructure” supporting well-being. But, the quality, functionality and position of GI in urban areas showed inequality in distribution. Frequently, societies with greater ethnic diversity, lower income and larger health inequality suffered from unsatisfactory or lack of access. GI is important in decision-making to address inequality. This work will also present an open-air activity for all generations: A reflective walk through the oldest part of Novi Sad (EU Capital of Culture 2022), as a part of Project Reflective citizens in Novi Sad. This walking tour was led by pupils from primary school - where all generations spend useful time in open space and a safe atmosphere walking tour, learning and listening about the cultural history of the oldest part of the city. It is vital to enhance urban planning and design practices in making healthier and more resilient communities. It is necessary to underline the importance of planning green spaces that need time to form in urban areas, and which have proven to be very important for mental health in the midst of the pandemic crisis.

Costs of air pollution impact on health in the Western Balkans: preliminary results

Air pollution is the main environmental driver associated with health. It is well documented that poor air quality is responsible for increased risk of mortality and morbidity. The social cost of mortality in 2015 was estimated in 3 trillion (OECD, 2016). The Western Balkans (WB) comprise Albania, Bosnia and Herzegovina, Kosovo*, North Macedonia, Montenegro and Serbia covering area of 218 750 km2 and a population of 19.9 million with total GDP of €94.2 billion (Banja et al., 2020). The WB was selected for this study because it is one of the air pollution hotspots in Europe where the levels of PM2.5, PM10, NO2 and O3 are frequently above the EU Air Quality Directive guidelines. This situation has been associated with a higher proportion of premature deaths attributable to air pollution exposure (4-19% of total deaths) in this region compared to EU member states (EEA, 2021). The health impacts including mortality and morbidity were estimated for particulate matter PM2.5, ozone (O3) and nitrogen dioxide (NO2) at country and city level on the basis of exposure in 2019 derived from monitoring stations and model estimations. Mortality impacts were parameterised using the number of premature deaths. Morbidity costs included: chronic bronchitis, hospital admissions due to respiratory diseases, hospital admissions due to cardiovascular diseases, bronchitis in children, asthma in children, reduced activity days and work lost days. The costs of mortality attributable to air pollution were estimated on the basis of non-market welfare based methods (WTP approach) while morbidity costs were estimated mainly with market based methods combining both direct and indirect costs. The 2019 health costs, both per capita and as share of the GDP, associated with air pollution in the WB were considerably higher than those in EU27.

Introducing walkable cities as a Public Health intervention

COVID-19 pandemic yet again showed that health crises and epidemics are introducing urban planning as a public health response. Globally, we saw a renewed interest in urban environment and healthy living and the changes in urban environments which can make for a healthier living. Even before the pandemic, various urban concepts and models that take as basis a health-oriented, holistic approach are being implemented in many cities. To name a few: car-free centres or neighbourhoods, the so-called ‘Superblocks’, neighbourhoods with low-speed traffic, walkable and cyclable cities aiming at all amenities being easy reach so-called ‘15 Minutes city’. COVID-19 crisis only accelerated many of these initiatives and brought them to global level need and attention. Such interventions are being introduced to demotivate the use of polluting cars, to ease up and to promote healthy and active transportation such as walking and cycling. As a consequence, those interventions not only are hoped to lead to an increase in physical activity, but also better air quality, reduction of noise. Cities have accelerated urban transformations of the space for active transportation such as the introduction of more cycling lanes in their networks, transforming ‘car’ streets to mix use streets, etc. Particularly during the pandemic, the streets that were previously dominated by car use, parking lots, parking spaces, and car lanes have shifted their focus to the pedestrians, healthy and active mobility. Though, not so optimistic continuation of the speed of the changes in urban planning are seen at the end of the pandemic. It is still clear that spaces for people, spaces promoting mental health such as green spaces, green islands, green pedestrian streets and healthy mobility, are missing. Lockdown measures of reducing the car traffic and increasing the walkable spaces for citizens were primarily imposed to save public health but had one important co-benefit - improved air quality in many areas.

Health Experts’ voice for Healthier Choice – a call for Zero Air Pollution in the Western Balkans

In 2019, the European Environment Agency has shown that the fine particulate matter PM2.5 caused more than 25 000 premature deaths in six Western Balkans countries alone, namely Albania 4 000, Bosnia and Herzegovina 5 900, Kosovo* 2 800, Montenegro 900, North Macedonia 3 400 and Serbia 11 400. In the same year, more than 2 200 lives were lost due to nitrogen dioxide (NO2) and ozone (O3) pollution. Air pollution and climate change are major health problems in the region. Health experts in the Western Balkans region have joined forces to highlight the importance of air quality actions and achieving zero air pollution as a prevention intervention for public health. We brought together a call for the Western Balkans policy-makers to invite them to commit to full alignment of all national air quality standards with the World Health Organization guidelines, to establish regional intersectoral cooperation to accelerate the moving to zero pollution, to including health authorities, public health institutes, and medical societies, patient representative and all health care experts and providers; to end direct or indirect public subsidies of polluting processes, especially fossil fuel activities such as coal power plants; to finalise the process of the ratification of the Convention on Long-range Transboundary Air Pollution and its protocols; to support modelling to establish economy-wide emission reduction commitments for the five main pollutants; to develop and implement Air Quality Strategies; to increase the uptake of Best Available Technologies (BAT) in accordance with the Industrial Emissions Directive; to establish an adequate air quality monitoring system, and to including through accreditation of air quality monitoring networks. Public health experts from the WB, united in the regional call, highlight the urgent need for improvements in air quality in the region together with a zero air pollution objective and a timeline to reach it.

Poverty and energy issues as environmental and health challenges in SDGs

In 2019, 21.1 % of the EU-27 population were at risk of poverty or social exclusion. Energy poverty is one of many poverty forms and it is a widespread problem across Europe, as between 50 and 125 million people are unable to afford proper indoor thermal comfort. Energy poverty is linked to low household income, high energy costs and energy inefficient homes. These challenges are deeply connected with SDG7 and SDG1, and also produce environmental pollution. The roots of energy poverty are in polluting fuels that are the cheapest and at hand to the population in (risk of) poverty. Biomass heating is the inefficient use in old stoves and the lack of wood drying before use (the loss of up to 50% of the energy and higher energy costs of heating). Biomass and coal is also a major contributor to poor air quality in many European regions, especially in eastern part of the EU and Western Balkans. Biomass smoke contains health-damaging substances (particulate matter, PAHs etc). Studies on indoor air pollution show concentrations of PM10 may extremely exceed standards for ambient air pollution levels and put the people (mostly women and children), at increased risk of health impacts. Biomass burning also leads to the release of black carbon, which is not only a concern for health, but also as short-lived climate change forcer (SDG 13). A conservative estimate of the current contribution of biomass smoke to premature mortality in Europe amounts to at least 40,000 deaths per year. The inefficient use of the biomass means higher costs for already ‘disadvantaged' citizens and those in risk of (energy) poverty. Energy poverty is a distinct form of poverty associated with a range of adverse consequences for people's health and wellbeing (respiratory diseases, CVD, mental health, and stress associated with unaffordable energy bills). Poverty and energy issues as environmental and health challenges should seen through SDG 1 and SDG 7, but also through SDG 8, SDG1 1 and SD G3.

Delivering on the Green Deal’s zero pollution ambition for health

As part of an integrated approach, the EU Green Deal also includes a zero pollution ambition for a toxic-free environment. This is a much needed and overdue commitment to address the significant environmental health burden from pollution in Europe. Air pollution alone leads to 400,000 premature deaths annually, and the extent of the health harm from chemicals pollution, or effects from combined exposures are still under investigation. The next months will show if the EU Commission can deliver on their ambition, with the launch of a zero pollution action plan for air, water and soil, and the speed of the process to revise the EU's ambient air quality standards. In addition, the World Health Organization (WHO) is expected to launch updated air quality guidelines, following a scientific review which showed greater health harm from poor air quality. The presentation will provide an overview of the policy opportunities for public health professionals to be engaged in, to make the health case for zero harm from pollution, and zero delay in stopping pollution. A particular emphasis will be placed on showcasing the need for zero financing of pollution, as major investments for transformation under Just Transition and green recovery schemes are underway.

Body size and pubertal development explain ethnic differences in structural geometry at the femur in Asian, Hispanic, and white early adolescent girls living in the U.S

Variation in structural geometry is present in adulthood, but when this variation arises and what influences this variation prior to adulthood remains poorly understood. Ethnicity is commonly the focus of research of skeletal integrity and appears to explain some of the variation in quantification of bone tissue. However, why ethnicity explains variation in skeletal integrity is unclear.

METHODS

Here we examine predictors of bone cross sectional area (CSA) and section modulus (Z), measured using dual-energy X-ray absorptiometry (DXA) and the Advanced Hip Analysis (AHA) program at the narrow neck of the femur in adolescent (9-14 years) girls (n=479) living in the United States who were classified as Asian, Hispanic, or white if the subject was 75% of a given group based on parental reported ethnicity. Protocols for measuring height and weight follow standardized procedures. Total body lean mass (LM) and total body fat mass (FM) were quantified in kilograms using DXA. Total dietary and total dairy calcium intakes from the previous month were estimated by the use of an electronic semi-quantitative food frequency questionnaire (eFFQ). Physical activity was estimated for the previous year by a validated self-administered modifiable activity questionnaire for adolescents with energy expenditure calculated from the metabolic equivalent (MET) values from the Compendium of Physical Activities. Multiple regression models were developed to predict CSA and Z.

RESULTS

Age, time from menarche, total body lean mass (LM), total body fat mass (FM), height, total calcium, and total dairy calcium all shared a significant (p<0.05), positive relationship with CSA. Age, time from menarche, LM, FM, and height shared significant (p<0.05), positive relationships with Z. For both CSA and Z, LM was the most important covariate. Physical activity was not a significant predictor of geometry at the femoral neck (p≥0.339), even after removing LM as a covariate. After adjusting for covariates, ethnicity was not a significant predictor in regression models for CSA and Z.

CONCLUSION

Variability in bone geometry at the narrow neck of the femur is best explained by body size and pubertal maturation. After controlling for these covariates there were no differences in bone geometry between ethnic groups.

Calcium and dairy product modulation of lipid utilization and energy expenditure

OBJECTIVE

The purpose of this study was to investigate the impact of dietary calcium or dairy product intake on total energy expenditure (TEE), fat oxidation, and thermic effect of a meal (TEM) during a weight loss trial.

METHODS AND PROCEDURES

The intervention included a prescribed 500-kcal deficit diet in a randomized placebo-controlled calcium or dairy product intervention employing twenty-four 18 to 31-year-old (22.2+/-3.1 years, mean +/- s.d.) overweight women (75.5+/-9.6 kg). TEM and fat oxidation were measured using respiratory gas exchange after a meal challenge, and TEE was measured by doubly labeled water. Fat mass (FM) and lean mass (fat-free mass (FFM)) were measured by dual-energy X-ray absorptiometry. Subjects were randomized into one of these three intervention groups: (i) placebo (<800 mg/day calcium intake); (ii) 900 mg/day calcium supplement; (iii) three servings of dairy products/day to achieve an additional 900 mg/day.

RESULTS

There were no group effects observed in change in TEE; however, a group effect was observed for fat oxidation after adjusting for FFM (P=0.02). The treatment effect was due to an increase in fat oxidation in the calcium-supplemented group of 1.5+/-0.6 g/h, P=0.02. Baseline 25-hydroxyvitamin D (25OHD) was positively correlated with TEM (R=0.31, P=0.004), and trended toward a correlation with fat oxidation (P=0.06), independent of group assignment. Finally, the change in log parathyroid hormone (PTH) was positively correlated with the change in trunk FM (R=0.27, P=0.03).

DISCUSSION

These results support that calcium intake increases fat oxidation, but does not change TEE and that adequate vitamin D status may enhance TEM and fat oxidation.

Bone mineral and predictors of bone mass in white, Hispanic, and Asian early pubertal girls

Differences in bone among racial/ethnic groups may be explained by differences in body size and shape. Previous studies have not completely explained differences among white, Asian, and Hispanic groups during growth. To determine racial/ethnic differences and predictors of bone mass in early pubertal girls, we measured bone mineral content (BMC) in white, Hispanic, and Asian sixth-grade girls across six states in the United States. We developed models for predicting BMC for the total-body, distal radius, total-hip, and lumbar spine for 748 subjects. For each of the bone sites, the corresponding area from dual-energy X-ray absorptiometry (DXA) was a strong predictor of BMC, with correlations ranging 0.78-0.98, confirming that larger subjects have more BMC. Anthropometric measures of bone area were nearly as effective as bone area from DXA at predicting BMC. For total-body, distal radius, lumbar spine, and total-hip BMC, racial/ethnic differences were explained by differences in bone area, sexual maturity, physical activity, and dairy calcium intake. Bone size explained most of the racial/ethnic differences in BMC, although behavioral indicators were also significant predictors of BMC.

A comparison of fatigue failure responses of old versus middle-aged lumbar motion segments in simulated flexed lifting

STUDY DESIGN

Survival analysis techniques were used to compare the fatigue failure responses of elderly motion segments to a middle-aged sample.

OBJECTIVES

To compare fatigue life of a middle-aged sample of lumbosacral motion segments to a previously tested elderly cohort. An additional objective was to evaluate the influence of bone mineral content on cycles to failure.

SUMMARY OF BACKGROUND DATA

A previous investigation evaluated fatigue failure responses of 36 elderly lumbosacral motion segments (average age, 81 +/- 8 years) subjected to spinal loads estimated when lifting a 9-kg load in 3 torso flexion angles (0 degrees, 22.5 degrees, and 45 degrees). Results demonstrated rapid fatigue failure with increased torso flexion; however, a key limitation of this study was the old age of the specimens.

METHODS

Each lumbosacral spine was dissected into 3 motion segments (L1-L2, L3-L4, and L5-S1). Motion segments within each spine were randomly assigned to a spinal loading condition corresponding to lifting 9 kg in 3 torso flexion angles (0 degrees, 22.5 degrees, or 45 degrees). Motion segments were statically loaded and allowed to creep for 15 minutes, then cyclically loaded at 0.33 Hz. Fatigue life was taken as the number of cycles to failure (10 mm displacement after creep loading).

RESULTS

Compared with the older sample of spines, the middle-aged sample exhibited increased fatigue life (cycles to failure) in all the torso flexion conditions. Increased fatigue life of the middle-aged specimens was associated with the increased bone mineral content (BMC) in younger motion segments (mean +/- SD, 30.7 +/- 11.1 g per motion segment vs. 27.8 +/- 9.4 g). Increasing bone mineral content had a protective influence with each additional gram increasing survival times by approximately 12%.

CONCLUSION

Younger motion segments survive considerably longer when exposed to similar spine loading conditions that simulate repetitive lifting in neutral and flexed torso postures, primarily associated with the increased bone mineral content possessed by younger motion segments. Cycles to failure of young specimens at 22.5 degrees flexion were similar to that of older specimens at 0 degrees flexion, and survivorship of young specimens at 45 degrees flexion was similar to the older cohort at 22.5 degrees.

Orthopedic outcomes of long-term daily corticosteroid treatment in Duchenne muscular dystrophy

OBJECTIVE

To document the effects of long-term daily corticosteroid treatment on a variety of orthopedic outcomes in boys with Duchenne muscular dystrophy.

METHODS

We reviewed the charts of 159 boys with genetically confirmed dystrophinopathies followed at the Ohio State University Muscular Dystrophy Clinic between 2000 and 2003. Charts were reviewed for ambulation status, type and duration of steroid treatment (if any), and orthopedic complications including presence and location of long bone fractures, vertebral compression fractures, and the presence and degree of scoliosis.

RESULTS

The cohort consisted of 143 boys (16 boys with Becker dystrophy were excluded); 75 had been treated with steroids for at least 1 year, whereas 68 boys had never been treated or had received only a brief submaximal dose. The mean duration of daily steroid treatment was 8.04 years. Treated boys ambulated independently 3.3 years longer than the untreated group (p < 0.0001) and had a lower prevalence of scoliosis than the untreated group (31 vs 91%; p < 0.0001). The average scoliotic curve was also milder in the treated group (11.6 degrees) compared with the untreated group (33.2 degrees; p < 0.0001). Vertebral compression fractures occurred in 32% of the treated group, whereas no vertebral fractures were discovered in the steroid naive group (p = 0.0012). Long bone fractures were 2.6 times greater in steroid-treated patients.

CONCLUSIONS

Although boys with Duchenne muscular dystrophy on long-term corticosteroid treatment have a significantly decreased risk of scoliosis and an extension of more than 3 years' independent ambulation, they are at increased risk of vertebral and lower limb fractures compared with untreated boys.

Potential use of biochemical markers of bone turnover for assessing the effect of calcium supplementation and predicting fracture risk

BACKGROUND

Biochemical markers of bone remodeling have been extensively used (independent of bone mass measurements) to document the efficacy of various anticatabolic and anabolic bone-modifying medications in reducing fracture risk. Nonetheless, their usefulness in determining the effectiveness of osteoporosis prevention and treatment, particularly calcium supplementation, has not been well established.

OBJECTIVE

This article reviews the use of biochemical markers of bone remodeling as a measure of the effect of calcium supplementation and the implications for prediction of fracture risk.

METHODS

A generalized search of MEDLINE from 1966 through April 2004 using the terms osteoporosis, fracture risk, and the specific bone biomarkers of interest was conducted to identify articles relating to these biomarkers and their relationship to prediction of fracture risk. A second MEDLINE search for the same period used the terms calcium, biological markers, and fracture risk to identify studies of calcium supplementation and bone biomarkers. In both cases, the reference lists of identified review articles were searched for additional publications.

RESULTS

: Several biochemical markers of bone remodeling have been shown to be positively correlated with bone mineral density and fracture risk. Furthermore, calcium supplementation has been shown to have a significant correlation with levels of a number of these biomarkers (P < 0.05): the markers of bone formation procollagen type I carboxy and amino terminal peptides and serum bone-specific alkaline phosphatase, and the markers of bone resorption urinary hydroxyproline, urinary pyridinoline, urinary deoxypyridinoline, urinary amino terminal crosslinked telopeptide, and urinary and serum carboxy terminal crosslinked telopeptide.

CONCLUSIONS

Calcium supplementation has a significant effect on a number of biomarkers of bone remodeling, an effect that is, in turn, correlated with decreased fracture risk. Most studies of the efficacy of calcium supplementation in reducing bone remodeling and influencing bone mineral density and fracture risk have involved calcium carbonate, although a few studies have found that other calcium salts may produce similar results.

Calcium supplementation and bone mineral density in females from childhood to young adulthood: a randomized controlled trial

BACKGROUND

Short-term studies established that calcium influences bone accretion during growth. Whether long-term supplementation influences bone accretion in young adults is not known.

OBJECTIVE

This study evaluated the long-term effects of calcium supplementation on bone accretion among females from childhood to young adulthood.

DESIGN

A 4-y randomized clinical trial recruited 354 females in pubertal stage 2 and optionally was extended for an additional 3 y. The mean dietary calcium intake of the participants over 7 y was approximately 830 mg/d; calcium-supplemented persons received an additional approximately 670 mg/d. Primary outcome variables were distal and proximal radius bone mineral density (BMD), total-body BMD (TBBMD), and metacarpal cortical indexes.

RESULTS

Multivariate analyses of the primary outcomes indicated that calcium-supplementation effects vary over time. Follow-up univariate analyses indicated that all primary outcomes were significantly larger in the supplemented group than in the placebo group at the year 4 endpoint. However, at the year 7 endpoint, this effect vanished for TBBMD and distal radius BMD. Longitudinal models for TBBMD and proximal radius BMD, according to the time since menarche, showed a highly significant effect of supplementation during the pubertal growth spurt and a diminishing effect thereafter. Post hoc stratifications by compliance-adjusted total calcium intake and by final stature or metacarpal total cross-sectional area showed that calcium effects depend on compliance and body frame.

CONCLUSIONS

Calcium supplementation significantly influenced bone accretion in young females during the pubertal growth spurt. By young adulthood, significant effects remained at metacarpals and at the forearm of tall persons, which indicated that the calcium requirement for growth is associated with skeletal size. These results may be important for both primary prevention of osteoporosis and prevention of bone fragility fractures during growth.

Calcium Needs in Children

Adequate calcium intake and physical activity during childhood and adolescence may be an important factor in bone acquisition and primary prevention of osteoporosis. Inadequate calcium intake during the pubertal growth spurt, in particular, may compromise an individual's volumetric bone density and predispose children to bone fragility fractures. In addition, it may compromise an individual's ability to reach his or her genetic potential in bone mass acquisition, or peak bone mass. National standards have been set for optimal calcium intake for childhood and adolescence. Most children and teenagers do not meet these requirements; therefore, there is a strong need to influence their behavior to consume foods rich in calcium.

Nutrition influences skeletal development from childhood to adulthood: a study of hip, spine, and forearm in adolescent females

This study evaluated the long-term efficacy of supplemental calcium and dairy products on bone mineral areal density of the hip and spine and on the bone geometry and volumetric bone mineral density of the forearm in young females during late adolescence. The study was conducted among participants of a randomized double-blinded, placebo-controlled clinical trial with calcium supplements and among participants of an observational study with higher consumption of dairy products. Hip and spine measurements by dual-energy X-ray absorptiometry were done every 6 mo (dairy group every 12 mo) during last 3 y of the follow-up while peripheral quantitative computerized tomography of the forearm was done at the last visit. The results of the study show a positive influence of calcium supplementation and dairy products on bone mineral density of the hip and the forearm. Dairy products were also associated with a higher bone mineral density of the spine while calcium supplementation did not have an effect. Calcium exerts its action on bone accretion during growth primarily by influencing volumetric bone mineral density while milk may have an additional impact on bone growth and periosteal bone expansion.

Selenium intakes, absorption, retention, and status in adolescent girls

OBJECTIVES

To assess selenium intakes, absorption, retention, and status in healthy adolescent girls and the effect of calcium supplementation on selenium parameters.

DESIGN

Annual 2-week study conducted each year for 3 consecutive years in which yearly selenium intakes, absorption, and retention and blood selenium status were measured.

SETTING

A metabolic unit in a large metropolitan hospital located in Columbus, Ohio--a low selenium region of the United States.

SUBJECTS

Healthy white girls aged 11 to 14 years (n=16) enrolled in a calcium balance study and randomly assigned to receive a placebo of methylcellulose (n=9) or a calcium supplement containing 1,000 mg supplemental calcium as calcium citrate malate (n=7).

INTERVENTIONS

Each subject consumed a diet with approximately 100 microg selenium/day during the yearly 2-week balance studies.

RESULTS

Selenium status measurements (serum and erythrocyte selenium and glutathione peroxidase activity) were all within normal ranges for adults during the study. Apparent selenium absorption averaged 71%, 76%, and 74% for years 1, 2, and 3 of the study, respectively, and did not vary significantly (P>.05). Average daily selenium retention did not differ among the years of the study (P>.05) and indicated that the usual selenium intake was approximately 100 microg daily. Measurements of selenium status and retention did not differ between calcium-supplemented and placebo groups.

CONCLUSIONS

An intake of approximately 100 microg selenium/day is the typical intake of the mineral among the subjects and appeared adequate to maintain selenium status in these healthy adolescent girls; in addition, calcium supplementation of 1,000 mg daily does not have a negative impact on selenium parameters.

Comparison of absorptiometric evaluations from total-body and local-regional skeletal scans

The most common measurement sites for dual-energy absorptiometry (DXA) in clinical practice are posteroanterior (PA) spine and femur. However, other skeletal regions may provide different bone density information. The purpose of this study was to establish the least number of DXA measurements needed to obtain complete information about bone. A total of 262 normal female subjects, 8-50, were measured on a Lunar DPX-L scanner under total body, PA spine, lateral spine, and femur protocol. Forearm measurements were performed with a Lunar SP2 single-photon absorptiometry scanner. The various measurements were compared based on a linear regression model. The correlation coefficients for bone mineral density (BMD) between adjacent vertebrae were 0.92-0.95, and the associated standard errors of the estimate (SEE) were 4.5-5.5%. Total-body BMD can best predict BMD of the trunk, arms, and legs (SEE<4.3%), but least that of the lateral view of the spine (SEE>13.9%). BMD values of the leg from total-body scans predict those from the femoral neck with an error of 9.0%, and those of the trochanteric region with 11.1%. The error between adjacent vertebrae (6%) is considered acceptable, then a total-body measurement combined with a lateral view of the spine and a femur scan are adequate.

Iron status, menarche, and calcium supplementation in adolescent girls

The effects of growth, menstrual status, and calcium supplementation on iron status were studied over 4 y in 354 girls in pubertal stage 2 who were premenarcheal at baseline (x+/-SD age: 10.8+/-0.8 y). Girls were randomly assigned to placebo or treatment with 1000 mg Ca/d as calcium citrate malate. Anthropometric characteristics, bone mass, and nutritional status were measured biannually; ferritin was measured annually; and red blood cell indexes were determined at 4 y. The simultaneous effects of iron intake and menstrual status on serum ferritin, after change in lean body mass (LBM) was controlled for, were evaluated in subjects in the upper and lower quartiles of cumulative iron intake. The average maximal accumulation of LBM (386 g/mo; 95% CI: 372, 399) occurred 0.5 y before the onset of menarche. Change in LBM was a significant predictor of serum ferritin (P < 0.0001), with a negative influence on iron status (t ratio=-4.12). The 2 fitted mathematical models representing ferritin concentrations of subjects in the upper and lower quartiles of cumulative iron intake were significantly different (P < 0.018). The regression line of the ferritin concentration in menstruating girls with high iron intakes had a less negative slope than the line fit to serum ferritin concentrations in girls with low iron intakes (NS). Serum ferritin concentrations at 0, 1, 2, 3, and 4 y were not significantly different between groups. In addition, there was no significant difference between groups in any of the red blood cell indexes. In summary, growth spurt and menstrual status had adverse effects on iron stores in adolescent girls with low iron intakes (<9 mg/d), whereas long-term supplementation with calcium (total intake: approximately 1500 mg/d) did not affect iron status.

Relation of nutrition, body composition and physical activity to skeletal development: a cross-sectional study in preadolescent females

OBJECTIVE

To examine the relation of anthropometric and growth parameters (weight, stature, body composition, age, and skeletal age), nutritional factors, and physical activity to the total body and radius bone mineral density and content and radiogrammetry parameters of the second metacarpal.

STUDY DESIGN

The study was a cross-sectional evaluation of 456 healthy, Caucasian girls, ages 8 to 13 years. Multiple regression models were created based on Cp statistics to determine the association between bone parameters and various independent variables.

RESULTS

Mean calcium intake was 956+/-381 mg/day, about 20% below the RDA of 1200 mg/day and about 36% below the threshold intake of approximately 1500 mg/day. The most significant predictors for total body and radius bone mineral density were corresponding bone areas, lean body mass, body fat, skeletal age, dietary calcium, and stature (only for total body) with corresponding R2(adjusted) of 48% and 36%. The total body and radius bone mineral content was positively associated with corresponding bone areas, lean body mass, body fat, calcium intake, and skeletal age with corresponding R2(adjusted) of 86% and 72%. Energy expenditure (corrected for BMI) was stratified into quartiles and bone mass parameters were distributed accordingly. A statistically significant difference in total body and radius bone mineral density and content was noted between the fourth and lower quartiles (ANOVA, p<0.05 to p<0.0001).

CONCLUSION

The most significant predictors of bone mass in preadolescent females evaluated in this study are bone area, lean body mass, body fat, skeletal age and dietary calcium.

Leptin is inversely related to age at menarche in human females

Over the last century there has been a trend toward an earlier onset of menarche attributed to better nutrition and body fatness. With the discovery of the obesity gene and its product, leptin, we reexamined this hypothesis from a new perspective. As delayed menarche and leanness are considered risk factors for osteoporosis, we also evaluated the relation between leptin and bone mass. Body composition and serum leptin levels were measured, and the timing of menarche was recorded in 343 pubertal females over 4 yr. Body composition was measured by dual x-ray absorptiometry, and leptin by a new RIA. All participants were premenarcheal at baseline (aged 8.3-13.1 yr). Leptin was strongly associated with body fat (r = 0.81; P < 0.0001) and change in body fat (r = 0.58; P < 0.0001). The rise in serum leptin concentration up to the level of 12.2 ng/mL (95% confidence interval, 7.2-16.7) was associated with the decline in age at menarche. An increase of 1 ng/mL in serum leptin lowered the age at menarche by 1 month. A serum leptin level of 12.2 ng/mL corresponded to a relative percent body fat of 29.7%, a body mass index of 22.3, and-body fat of 16.0 kg. A gain in body fat of 1 kg lowered the timing of menarche by 13 days. Leptin was positively related to bone area (r = 0.307; P < 0.0001) and change in bone area (r = 0.274; P < 0.0001). A critical blood leptin level is necessary to trigger reproductive ability in women, suggesting a threshold effect. Leptin is a mediator between adipose tissue and the gonads. Leptin may also mediate the effect of obesity on bone mass by influencing the periosteal envelope. This may have implications for the development of osteoporosis and osteoarthritis.

Calcitriol and bone mass accumulation in females during puberty

Adolescence is characterized by rapid skeletal development and high demands for bone minerals. Though the stimulative effect of calcitriol on intestinal calcium and phosphorus absorption is well understood, its effect on bone development is not completely clear. It may be directly involved in the facilitation of calcium economy during this critical phase of skeletal development. Therefore, we evaluated the serum concentrations of calcitriol in relation to skeletal development in a cross-sectional study of 178 healthy Caucasian females during different pubertal stages, extending from childhood to young adulthood. In addition, a subsample of 57 younger girls was followed for a 1-year period to evaluate the association among serum calcitriol, nutrition parameters (dietary calcium, phosphorus, and vitamin D), bone mass accumulation, and biochemical markers of bone turnover. The serum calcitriol concentration in a cross-sectional sample was the highest during pubertal growth spurt (sexual maturity index 3-4, age 11-13 years) (ANOVA; F = 2.4945; P = 0.0329). This correlated to the peak skeletal calcium accretion (g/year) and bone mass accumulation in total body and forearm. In a longitudinal sample, there was a positive association between annual change in TBBMC (P = 0.0255); TBBMD (P = 0.0168); proximal radius (1/3 distance from styloid process) BMC (P = 0.0096); BMD (P = 0.0541), and baseline calcitriol level in forward stepwise regression analyses. The results of the forward stepwise regression analyses with serum calcitriol as a dependent variable and different serum, urinary, and dietary parameters measured at baseline (age 11 years, n = 114) and after 1 year (age 12 years, n = 57) showed that osteocalcin was positively associated with calcitriol in both years; more so in a second year (P = 0.0514, P < 0.001, respectively). Dietary vitamin D and phosphorus showed negative association with serum calcitriol at age 11, and dietary Ca and P were selected at age 12. The results of this study show that calcitriol is a significant correlate of bone mass accumulation during pubertal growth, presumably in response to the high requirements for calcium during this critical phase of skeletal development.

Gain in body fat is inversely related to the nocturnal rise in serum leptin level in young females

Both genetic and environmental factors contribute to adolescent obesity. Evidence of a genetic basis for obesity development is substantial, although the exact mechanism of action has yet to be identified. The purpose of this study was to document the circadian rhythmicity of the serum leptin level in young females and to assess the impact of the change in body fat stores during growth on the nocturnal rise in the serum leptin level with implications for obesity traits. There was a significant rise in serum leptin at midnight and 0400 h, suggesting a diurnal variation in serum leptin concentrations (ANOVA F ratio = 6.2; P < 0.0001). There was also a strong association between relative total body fat and the average daytime serum leptin level (r = 0.78; P < 0.0001). The percent increase in the nocturnal leptin concentration was inversely related to the percent gain in total body fat (r = 0.45; P < 0.024). Forward stepwise regression analysis selected the change in total body fat over a 6-month interval as the most powerful determinant of the percent increase in the nocturnal leptin concentration (partial R2 = 0.203; beta = -0.450; SE of beta = 0.186; t = -2.418; P < 0.024). If the lack of a nocturnal rise in serum leptin persists over a longer period of time, it may have implications for the development of obesity, presumably by inadequate suppression of nighttime appetite.

Zinc balance in adolescent females consuming a low- or high-calcium diet

There is increasing evidence that calcium intake up to the threshold amount (1480 mg/d) increases bone mass during growth. However, there is concern that such a high calcium intake may interfere with the utilization of other nutrients such as zinc, which is also important for skeletal development. The purpose of our study was to investigate the effect of long-term calcium supplementation on zinc utilization in 26 adolescent females (mean +/- SD age 11.3 +/- 0.5 y) during a 14-d period. Each day subjects consumed a metabolic diet containing 722 mg Ca and 6.3 mg Zn. Participants were randomly assigned to receive either a placebo or a calcium supplement containing 1000 mg supplemental Ca/d as calcium citrate malate. Supplementation began 15 wk before the balance period to allow for adaptation to the greater calcium intake. Mean (+/-SD) zinc balance (0.8 +/- 0.8 compared with 0.3 +/- 1.1 mg/d, P = 0.23), fecal zinc (4.3 +/- 0.6 compared with 4.7 +/- 1.4 mg/d, P = 0.27), urinary zinc (0.4 +/- 0.2 compared with 0.5 +/- 0.1 mg/d, P = 0.55), and net zinc absorption (21% compared with 15%, P = 0.33) were not significantly different between the high- and low-calcium groups. Our results suggest that increasing the recommended dietary allowance of calcium to 1500 mg/d as recommended by the National Institutes of Health consensus panel will not have adverse effects on zinc utilization in adolescent females.

Nutrition, genetics and skeletal development

From infancy through young adulthood the activity of bone formation predominates, resulting in a steady accumulation of bone mass. As the rate of growth changes with age, so skeletal modeling progresses through phases of different intensity with time. This is paralleled by concomitant changes in bone and calcium metabolism. Bone modeling and skeletal consolidation probably result from a complex sequence of hormonal changes in interaction with nutritional factors. However, current knowledge of the role, sequence, and genetic regulation of hormonal events during puberty, and of the response of bone tissue in interaction with nutrition is limited. This interaction is now beginning to be elucidated. The importance of this interaction with regard to fracture epidemiology in children and peak bone mass acquisition has been discussed.

Skeletal age as a determinant of bone mass in preadolescent females

OBJECTIVE

To evaluate the association between chronological age, skeletal age, pubertal stage, and basic anthropometry with bone mass of the total body, forearm, and second metacarpal bone in 456 healthy Caucasian females, aged 8-13 years.

DESIGN

Total body and forearm bone measurements were performed by dual X-ray absorptiometry, while bone mass of the second metacarpal was assessed by radiogrammetry. Skeletal age (SA) was assessed by the FELS method and pubertal stage was self-determined by selecting corresponding illustrations of breast and public hair development. The Cp criterion was used to select the best multiple regression model containing the subset of independent variables with the least bias and best predictive ability for each of the measured bone mass variables.

RESULTS

Of all the independent variables, weight, stature, and SA emerged as the most significant predictors for almost all the bone mass variables. Multiple regression models were created based on the Cp criterion with the resulting R2 (adjusted) for bone mineral content of total body, proximal forearm, ultradistal forearm, length of second metacarpal, as well as of total, medullary, and cortical areas: 0.793, 0.523, 0.390, 0.602, 0.232, 0.073, and 0.264, respectively. The measured bone variables were also regressed on SA using either quadratic or linear equations, depending on the shape of the cubic splines used for the best curve fitting. Significant positive association (p < 0.0001) of SA and each of the bone variables was noted, the highest being with bone mineral density and content of total body (R2 = 0.176, 0.338) and proximal and ultradistal forearm (R2 = 0.216, 0.203, 0.106, 0.201), respectively, as well as with the length of the second metacarpal bone (R2 = 0.339). Chronological age and pubertal stage did not have statistically significant predictive abilities for bone mass variables in the multiple regression models.

CONCLUSIONS

We conclude that skeletal age is a powerful determinant of bone mass in children. It can be used as the criterion for the selection of a biologically homogeneous population with regard to bone mass. This may be important for the design of intervention studies targeting bone mass of children and adolescents.

Magnesium balance in adolescent females consuming a low- or high-calcium diet

Increasing emphasis is being placed on optimizing calcium intake during growth as a way to enhance peak bone mass. Although some studies in adults have shown that high calcium intake may negatively affect magnesium utilization, few data are available regarding the interaction of calcium and magnesium in healthy children. The purpose of our study was to measure the effect of calcium intake on magnesium balance in 26 adolescent girls (mean age 11.3 y) during a 14-d period. Subjects ate a controlled basal diet containing 667 mg Ca and 176 mg Mg. In addition to the basal diet, subjects were randomly assigned in a double-blind fashion to consume 1000 mg elemental Ca/d as calcium citrate malate or a placebo. Magnesium use did not differ between the low-calcium and high-calcium groups as measured by absorption (50% compared with 55%), urinary excretion (70 compared with 74 mg/d), and fecal excretion (88 compared with 79 mg/d). Accordingly, magnesium balance was not different in subjects consuming 667 or 1667 mg Ca/d and averaged 21 mg Mg/d for the whole study group. Magnesium balance was significantly correlated with magnesium intake (r = 0.511, P = 0.008) and magnesium absorption (r = 0.723, P < 0.001). Prediction intervals from the regression of magnesium balance on intake indicated that the current recommended dietary allowance of magnesium would result in magnesium balance > or = 8.5 mg/d in 95% of the girls. This value appears consistent with long-term accretion rates needed to account for the expansion of the total-body magnesium pool during growth. In summary, our observations support the adequacy of the current recommended dietary allowance for magnesium and indicate that alterations in magnesium utilization should not be anticipated in adolescent females consuming a high-calcium diet.

Urinary calcium, sodium, and bone mass of young females

Calcium is an important determinant of peak bone mass in young adults because of its influence on skeletal development during growth. Attainment of maximum peak bone mass requires optimal positive balance between calcium intake and obligatory losses of calcium, primarily in urine and feces. Urinary excretion is an important determinant of calcium retention in the body. Accordingly, the purpose of this study was to evaluate the influence of various nutrients on urinary calcium excretion, and to assess their impact on bone mass of young females, aged 8-13 y, during early puberty. The study was conducted in 381 healthy white females in pubertal stage 2. From each participant we collected basic anthropometric measurements, a 3-d food record, blood, a 24-h urine sample, and bone mass measurements of the total body and forearm by dual X-ray absorptiometry. Urinary sodium was found to be one of the most important determinants of urinary calcium excretion: [urinary calcium (mmol/d) = 0.01154 x urinary sodium (mmol/d) + 0.823], whereas calcium intake had relatively little impact: [urinary calcium (mmol/d) = 0.02252 x calcium intake (mmol/d) + 1.5261]. Urinary calcium was much higher at a calcium intake of approximately 37.5 mmol/d (1500 mg/d), supporting the notion that calcium is a threshold nutrient. Calcium intake had a significant positive influence on the bone mineral content and density of the whole body and radius shaft whereas urinary calcium had a negative influence, presumably by reducing calcium accretion into the skeleton.(ABSTRACT TRUNCATED AT 250 WORDS)

Supplementation trials with calcium citrate malate: evidence in favor of increasing the calcium RDA during childhood and adolescence

The vast majority of peak adult bone mass is accumulated by the time longitudinal growth is complete. As peak bone mass is an important determinant of future fracture risk, the goal of the current calcium recommended dietary allowance during youth is to provide a calcium intake that allows individuals to reach their full genetic potential for acquiring skeletal mass. The advent of controlled trials of calcium supplementation and total body bone mass measurements in children and adolescents provide the first direct way of determining the amount of calcium necessary to achieve optimal skeletal accretion. These studies indicate that the current RDAs are insufficient to support optimal bone mass gain during growth and development. Based on the recent intervention trials, recommendations are made for an RDA of 1250 mg during childhood and 1450 mg during adolescence. These values are consistent with established calcium balance intake thresholds for growth during pre-adolescence and adolescence.

The effects of gallium nitrate on osteopenia induced by ovariectomy and a low-calcium diet in rats

The effects of gallium nitrate (GN) were evaluated on osteopenia induced by ovariectomy (OVX) and a low-calcium diet (LCD) in Sprague-Dawley rats. Twenty-five rats (300-400 g) were randomized into four groups of 5-7 animals: (I) OVX LCD treated with GN for 22 weeks; (II) OVX LCD treated with GN for 10 weeks; (III) OVX LCD treated with saline; and (IV) sham-operated (SO), normal diet, treated with saline. GN-treated rats received a 30-mg/kg subcutaneous single dose of elemental gallium, followed by 10 mg/kg per week, whereas control animals received an equal volume of saline. All animals were euthanized at 22 weeks. Measurements of bone density and histomorphometry, performed on the proximal portion of the tibia, indicated significant bone loss in all OVX LCD animals. GN-treated rats in group I gained significantly less weight than those in the other groups, and their blood urea nitrogen increased, suggesting a nephrotoxic effect. After discontinuation of GN, rats in group II gained weight at the same rate as those which had received only saline. Bone formation rates in the GN-treated rats were double those of the saline-treated OVX animals and more than 10 times those of SO controls. Although the bone formation rate in GN-treated rats increased, GN had no effect in preventing the loss of bone surface, density and volume induced by OVX LCD. These findings suggest that although GN may enhance osteoblastic activity, this agent alone does not appear effective in the prevention of bone loss induced by OVX LCD.

A comparison of single photon and dual X-ray absorptiometry of the forearm in children and adults

We compared single photon absorptiometry (SPA) to dual x-ray absorptiometry (DXA) for determination of bone mineral content (BMC), bone mineral density (BMD), and bone width (BW) of the forearm. The SPA and DXA measurements were done on the same subjects, using Lunar densitometers. The measurements were performed over the proximal radius (1/3 shaft) of the nondominant arm in 285 healthy, Caucasian females and males, ages 9-53. Correlation, linear, and split regression analyses for all subjects, and for subgroups (adults and children), were performed to compare SPA and DXA measurements. Corresponding measurements performed on two densitometers were highly correlated: r = 0.987, 0.975, and 0.943 for BMC, BMD, and BW, respectively. The corresponding measurements were also very similar in value, ranging from 0.9% to 4.1% difference, although they were different statistically. Correlations dropped slightly when subjects were separated into adult and children subgroups, and therefore, split regression analysis was performed resulting in R2 (adjusted) values of 97.6%, 95.5%, and 89.0% for BMC, BMD, and BW, respectively. Because the group indicator was statistically significant (p < 0.001) only for the BMC measurements but not for BMD and BW, linear regression of the whole sample was done as well. The difference in fitted values between the two regression methods was insignificant; therefore, we concluded that linear regression was sufficient for description of the relationship between SPA and DXA measurements. The precision study showed that the DXA had better reproducibility than SPA. The DXA precision in vivo (CV%) for BMC, BMD, and BW was 1.06, 0.83, and 0.95, respectively; and the SPA precision for same variables was 2.08, 2.12, and 0.95, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Timing of peak bone mass in Caucasian females and its implication for the prevention of osteoporosis. Inference from a cross-sectional model

To determine the timing of peak bone mass and density, we conducted a cross-sectional study of bone mass measurements in 265 premenopausal Caucasian females, aged 8-50 yr. Bone mass and bone mineral density were measured using dual X-ray absorptiometry and single-photon absorptiometry at the spine (anteroposterior, lateral), proximal femur, radius shaft, distal forearm, and the whole body. Bone mass parameters were analyzed using a quadratic regression model and segmented regression models with quadratic-quadratic or quadratic-linear form. The results show that most of the bone mass at multiple skeletal locations will be accumulated by late adolescence. This is particularly notable for bone mineral density of the proximal femur and the vertebral body. Bone mass of the other regions of interest is either no different in women between the age of 18 yr and the menopause or it is maximal in 50-yr-old women, indicating slow but permanent bone accumulation continuing at some sites up to the time of menopause. This gain in bone mass in premenopausal adult women is probably the result of continuous periosteal expansion with age. Since rapid skeletal mineral acquisition at all sites occurs relatively early in life, the exogenous factors which might optimize peak bone mass need to be more precisely identified and characterized.

Calcium requirements for growth: are current recommendations adequate?

Peak adult bone mass is determined in each individual by a combination of endogenous and environmental factors. Insufficient accumulation of skeletal mass by the time young adulthood is reached appears to enhance the likelihood of fractures later in life. It is speculated that environment (nutrition and exercise) contributes to about 20% of the variance in bone mass. Although much is yet to be learned about how diet contributes to skeletal growth and development, it now appears that calcium intake may be an important factor in the attainment of peak bone mass. A review of the scientific literature suggests that the current recommended dietary allowance (RDA) for calcium may not be high enough to optimize the genetically programmed peak bone mass in a substantial number of growing individuals. New standards for dietary calcium intakes during growth may be indicated.