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

The Challenge of Growth Hormone Deficiency Diagnosis and Treatment during the Transition from Puberty into Adulthood

In children with childhood-onset growth hormone deficiency, replacement GH therapy is effective in normalizing height during childhood and achieving adult height within the genetic target range. GH has further beneficial effects on body composition and metabolism through adult life. The transition phase, defined as the period from mid to late teens until 6-7 years after the achievement of final height, represents a crucial time for reassessing children's GH secretion and deciding whether GH therapy should be continued throughout life. Evidence-based guidelines for diagnosis and treatment of growth hormone deficient children during transition are lacking. The aim of this review is to critically review the up-to-date evidence on the best management of transition patients in order to ensure the correct definitive diagnosis and establish the appropriate therapeutic regimen.

Influence of heredity and environment on peak bone density: a review of studies in Croatia

One of the main determinants of who will develop osteoporosis is the amount of bone accumulated at peak bone density. There is poor agreement, however, on when peak bone density occurs. Ethnic differences were observed in age at peak bone density and their correlates. Since the diagnosis of osteoporosis and osteopaenia is based on the comparison between patients' bone mineral density (BMD) and optimal peak bone density in healthy young people (T-score), it is of great importance that each country should provide its own reference peak bone density data.This review article presents our published results on peak bone density in Croatia and compares them with findings in other populations. Our research included 18 to 25-year-old students from Zagreb University and their parents. The results showed that peak bone mass in young Croatian women was achieved before the age of twenty, but BMD continued to increase after the mid-twenties in the long-bone cortical skeleton. BMD was comparable to the values reported by the National Health and Nutrition Examination Survey (NHANES) and other studies that included the same age groups, except for the cortical part of the radius, where it was significantly lower. Men achieved peak bone density in the spine later than women, which cannot be explained by different diet or physical activity. As expected, heredity was more important for peak bone density than the environmental factors known to be important for bone health. However, the influence of heredity was not as strong as observed in most other populations. It was also weaker in the cortical than in the trabecular parts of the skeleton. Future research should include young adolescent population to define the exact age of achieving peak bone density in different skeletal sites.

Influence of basal energy expenditure and body composition on bone mineral density in postmenopausal women

Background

The aim of this study was to investigate the influence of body mass index, body weight, lean mass, fat mass, and basal energy expenditure on bone mineral density in postmenopausal women.

Methods

This was a cross-sectional, descriptive study of a sample of 50 women, with minimum time since menopause between 1 and 10 years. Bone mineral density was assessed at the lumbar spine (L2–L4), femoral neck, Ward’s triangle, and trochanter using dual-energy X-ray absorptiometry. Body mass index, lean mass, fat mass, and basal energy expenditure were measured by bioimpedance.

Results

The mean age of the women was 51.49 ± 3.86 years and time since menopause was 3.50 ± 2.59 years. Significant negative correlations were found between chronological age and lumbar spine, femoral neck, Ward’s triangle, and trochanteric bone mineral density. In regard to time since menopause, we also observed significant negative correlations with bone mineral density at the lumbar spine and Ward’s triangle. The following significant positive correlations were recorded: body mass index with bone mineral density at the femoral neck and trochanter; fat mass with bone mineral density at the femoral neck and trochanter; lean mass with bone mineral density at the lumbar spine, femoral neck, and trochanter; and basal energy expenditure with bone mineral density at all sites assessed. On the other hand, the multiple linear regression model showed that: 20.2% of bone mineral density variability at the lumbar spine is related to lean mass and time since menopause; 22.3% of bone mineral density variability at the femoral neck is related to body weight and age; 18.9% of bone mineral density variability at Ward’s triangle is related to age and basal energy expenditure; and 39% of bone mineral density variability at the trochanter is related to body mass index, age, and menarche.

Conclusion

Changes in bone mineral density, specific for each skeletal site, are influenced by age, time since menopause, body weight, body mass index, lean mass, and basal energy expenditure. Lean mass and basal energy expenditure positively influenced bone mineral density at the lumbar spine and Ward’s triangle, with a predominance of trabecular bone.

Longitudinal assessment of bone mineral density in children and adolescents with inflammatory bowel disease

OBJECTIVES

Low bone mineral density (BMD) is recognized as a potential problem in children with inflammatory bowel disease (IBD). We aimed to describe the longitudinal development of BMD in a population of Swedish pediatric patients with IBD.

METHODS

A total of 144 patients with IBD (93 males; 83 with ulcerative colitis [UC], 45 with Crohn disease [CD]) were examined with dual-energy x-ray absorptiometry at baseline. At follow-up 2 years later, 126 of the initial 144 patients were reexamined. BMD values are expressed as z scores.

RESULTS

Children with UC and CD had significantly lower mean BMD z scores for the lumbar spine (LS) at baseline and after 2 years. The reduction in BMD was equally pronounced in patients with UC and CD, and neither group improved their z score during the follow-up period. Furthermore, significantly lower mean BMD z scores for the LS were found at baseline in boys (-1.1 SD, ±2.7 SD, P < 0.001), but not in girls (-0.0 SD, ±3.0 SD). This finding remained unchanged at follow-up. Subanalyses of the different age groups at baseline showed the lowest BMD values in the group of patients ages 17 to 19 years in boys (mean z score for the LS 1.59 SD, ±3.1 SD) and in girls (mean z score for the LS -3.40 SD, ±3.1 SD); however, at follow-up, these patients had improved their BMD significantly (mean change z score for the LS 1.00 SD, 95% CI 0.40-1.60; 1.90 SD, 95% CI 0.60-3.20).

CONCLUSIONS

In this longitudinal study, the entire group of pediatric patients with IBD showed permanent decreases in their BMD z scores for the LS; however, our data indicate that afflicted children have the potential to improve their BMD by the time they reach early adulthood.

Runx-2 gene expression is associated with age-related changes of bone mineral density in the healthy young-adult population

Bone mineral density (BMD) and peak bone mass (PBM) are important determinants of skeletal resistance. The development of bone densitometry improved the possibility of studying BMD and the influence of genetic and environmental factors on bone. Heredity factors are important for BMD, and Runx-2 is accepted as a regulator of osteoblasts and bone formation. The aim of our study was to evaluate the behavior of Runx-2 during skeletal maturity in the healthy young-adult population. We analyzed spine and hip BMD in 153 volunteers, 98 women and 55 men, using dual-energy X-ray absorptiometry. In a subgroup of these volunteers, a sample of peripheral blood was taken to perform gene expression analysis of Runx-2 both in peripheral mesenchymal stem cells (MSCs; 28 subjects) and in peripheral mononuclear cells (PBMCs; 140 subjects). In our work BMD was comparable in both genders after puberty, then became higher in men than women during the third and fourth decades. PBM was achieved in the third decade in women and in the fourth in men. More interestingly, Runx-2 gene expression highly correlated with BMD in both genders. MSCs and PBMCs showed the same gene expression profile of Runx-2. In conclusion, PBM is reached earlier in females, BMD becomes higher in males later in life, and BMD and PBM are strictly associated with Runx-2. In addition, PBMC should be considered an important source for gene expression analysis in bone diseases.

Calcium metabolism and correcting calcium deficiencies

Calcium is the most abundant cation in the human body, of which approximately 99% occurs in bone, contributing to its rigidity and strength. Bone also functions as a reservoir of Ca for its role in multiple physiologic and biochemical processes. This article aims to provide a thorough understanding of the absorptive mechanisms and factors affecting these processes to enable one to better appreciate an individual's Ca needs, and to provide a rationale for correcting Ca deficiencies. An overview of Ca requirements and suggested dosing regimens is presented, with discussion of various Ca preparations and potential toxicities of Ca treatment.

MRI-measured pelvic bone marrow adipose tissue is inversely related to DXA-measured bone mineral in younger and older adults

BACKGROUND/OBJECTIVES

Recent research has shown an inverse relationship between bone marrow adipose tissue (BMAT) and bone mineral density (BMD). There is a lack of evidence at the macro-imaging level to establish whether increased BMAT is a cause or effect of bone loss. This cross-sectional study compared the BMAT and BMD relationship between a younger adult group at or approaching peak bone mass (PBM; age 18.0-39.9 years) and an older group with potential bone loss (PoBL; age 40.0-88.0 years).

SUBJECTS/METHODS

Pelvic BMAT was evaluated in 560 healthy men and women with T1-weighted whole-body magnetic resonance imaging. BMD was measured using whole-body dual-energy X-ray absorptiometry.

RESULTS

An inverse correlation was observed between pelvic BMAT and pelvic, total and spine BMD in the younger PBM group (r=-0.419 to -0.461, P<0.001) and in the older PoBL group (r=-0.405 to -0.500, P<0.001). After adjusting for age, sex, ethnicity, menopausal status, total body fat, skeletal muscle, subcutaneous and visceral adipose tissue, neither subject group (younger PBM vs older PoBL) nor its interaction with pelvic BMAT significantly contributed to the regression models with BMD as dependent variable and pelvic BMAT as independent variable (P=0.434-0.928).

CONCLUSIONS

Our findings indicate that an inverse relationship between pelvic BMAT and BMD is present both in younger subjects who have not yet experienced bone loss and also in older subjects. These results provide support at the macro-imaging level for the hypothesis that low BMD may be a result of preferential differentiation of mesenchymal stem cells from osteoblasts to adipocytes.

Do premenopausal women with major depression have low bone mineral density? A 36-month prospective study

Background

An inverse relationship between major depressive disorder (MDD) and bone mineral density (BMD) has been suggested, but prospective evaluation in premenopausal women is lacking.

Methods

Participants of this prospective study were 21 to 45 year-old premenopausal women with MDD (n = 92) and healthy controls (n = 44). We measured BMD at the anteroposterior lumbar spine, femoral neck, total hip, mid-distal radius, trochanter, and Ward's triangle, as well as serum intact parathyroid hormone (iPTH), ionized calcium, plasma adrenocorticotropic hormone (ACTH), serum cortisol, and 24-hour urinary-free cortisol levels at 0, 6, 12, 24, and 36 months. 25-hydroxyvitamin D was measured at baseline.

Results

At baseline, BMD tended to be lower in women with MDD compared to controls and BMD remained stable over time in both groups. At baseline, 6, 12, and 24 months intact PTH levels were significantly higher in women with MDD vs. controls. At baseline, ionized calcium and 25-hydroxyvitamin D levels were significantly lower in women with MDD compared to controls. At baseline and 12 months, bone-specific alkaline phosphatase, a marker of bone formation, was significantly higher in women with MDD vs. controls. Plasma ACTH was also higher in women with MDD at baseline and 6 months. Serum osteocalcin, urinary N-telopeptide, serum cortisol, and urinary free cortisol levels were not different between the two groups throughout the study.

Conclusion

Women with MDD tended to have lower BMD than controls over time. Larger and longer studies are necessary to extend these observations with the possibility of prophylactic therapy for osteoporosis.

Trial Registration

ClinicalTrials.gov NCT 00006180

Changes in the vitamin D endocrine system and bone turnover after oral vitamin D3 supplementation in healthy adults: results of a randomised trial

BACKGROUND

There is uncertainty as to which intake of vitamin D is needed to suppress PTH and maintain normal bone metabolism throughout winter at northern latitudes. We aimed to investigate whether four weeks' daily supplementation with 10 μg vitamin D3 from fish oil produced a greater change in serum vitamin D metabolites, parathyroid hormone, and bone turnover in healthy adults compared with solid multivitamin tablets. Furthermore, it was studied whether age, gender, ethnic background, body mass index, or serum concentrations at baseline predicted the magnitude of change in these parameters.

METHODS

Healthy adults aged 19-48 years living in Oslo, Norway (59°N) were randomised to receive a daily dose of 10 μg vitamin D3 given as fish oil capsules or multivitamin tablets during four weeks in late winter. Serum samples from baseline and after 28 days were analysed for 25-hydroxyvitamin D (s-25(OH)D), 1,25-dihydroxyvitamin D (s-1,25(OH)2D), intact parathyroid hormone (s-iPTH), and osteoclast-specific tartrate-resistant acid phosphatase 5b (s-TRACP). Fifty-five eligible participants completed the intervention (74% of those randomised).

RESULTS

S-25(OH)D increased by mean 34.1 (SD 13.1) nmol/l, p < 0.001; s-iPTH decreased by mean 1.2 (SD 2.5) pmol/l, p = 0.001; s-1,25(OH)2D increased by mean 13 (SD 48) pmol/l, p = 0.057; and s-TRACP increased by mean 0.38 (SD 0.33) U/l, p < 0.001. For all these parameters, there was no difference between fish oil and multivitamin formulation. Baseline concentrations were the only independent predictors of changes in biochemical parameters.

CONCLUSIONS

Four weeks of daily supplementation with 10 μg vitamin D3 decreased mean s-iPTH and increased s-TRACP concentration, and this did not differ by mode of administration. Our results suggest an increased bone resorption following vitamin D supplementation in young individuals, despite a decrease in parathyroid hormone levels.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01482689.

High bone density and bone health

The aim of this paper is to review the main aspects related to high bone density (HBD) as well as to discuss the physiologic mechanisms involved in bone health. There are still no well-defined criteria for identification of individuals with HBD and there are few studies on the topic. Most studies demonstrate that overweight, male gender, black ethnic background, physical activity, calcium and fluoride intake and use of medications such as statins and thiazide diuretics play a relevant and positive role on bone mineral density. Moreover, it is known that individuals with certain diseases such as obesity, diabetes, estrogen receptor-positive breast or endometrial cancer have greater bone density than healthy individuals, as well as athletes having higher bone density than non-athletes does not necessarily mean that they have healthy bones. A better understanding of risk and protective factors may help in the management of patients with bone frailty and have applicability in the treatment and in the prevention of osteoporosis, especially intervening on non-modifiable risk factors.

Are existing measures of overall diet quality associated with peak bone mass in young premenopausal women?

BACKGROUND

  Low peak bone mass in young adulthood is associated with an increased risk of osteoporosis and fracture after menopause, and an understanding of the modifiable factors that contribute to low peak bone mass is important for fracture prevention. Diet is an important modifiable factor linked to bone health and, although studies have examined the role of individual dietary components in bone health, bone growth and maintenance are complex processes, and such studies may not adequately represent the role of diet in these processes.

METHODS

  To address this issue, a cross-sectional analysis of 226 healthy, premenopausal women aged 18-30 years was conducted to determine whether existing indices of overall diet quality are associated with bone density in premenopausal women nearing peak bone mass. Bone density was measured using dual-energy X-ray absorptiometry and diet quality was measured using two overall diet scores based on current dietary guidelines: the Recommended Food Score and the Alternate Healthy Eating Index (AHEI).

RESULTS

  In the multiple linear regression, bone density did not increase across quartiles of either diet quality score and was not associated with continuous diet quality variables. Furthermore, none of the individual AHEI components (e.g. fruit intake, vegetable intake) were associated with bone density.

CONCLUSIONS

  These findings suggest that existing diet quality scores are not appropriate for studies of peak bone mass, most likely because they do not give sufficient weight to foods and nutrients important to bone health. We recommend the development of a diet pattern index that better predicts bone mass measures.

Epidemiology and structural basis of racial differences in fragility fractures in Chinese and Caucasians

Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.

Obesity is a risk factor for fracture in children but is protective against fracture in adults: a paradox

With the rise in obesity worldwide, an important debate has developed as to whether excess fat has a detrimental or protective effect on skeletal health in children and adults. Obese children appear to be over represented in fracture groups and recent evidence suggests that fat may be detrimental to bone accrual in children, although this effect may be confined to adolescence during rapid skeletal growth. Fat induced alterations in hormonal factors and cytokines during growth may play a pivotal role in disturbing bone accrual. In contrast, the widely accepted opinion is that fat appears to be protective of bone in adults and minimises bone loss in postmenopausal women. Recent evidence suggests that in adults, site specific fat depots may exert differing effects on bone (with visceral fat acting as a pathogenic fat depot and subcutaneous fat exerting protective effects), and that the effects of fat mass on bone and fracture risk may vary by skeletal site; obesity protects against hip and vertebral fractures but is a risk factor for fractures of the humerus and ankle. The incidence of fracture during adolescence is rising and osteoporosis remains a considerable health burden in older adults. Understanding the effects of fat mass on bone during growth and early adulthood is vital in informing future health strategies and pharmacotherapies to optimise peak bone mass and prevent fracture.

Bone mineral density and body composition in girls with idiopathic central precocious puberty before and after treatment with a gonadotropin-releasing hormone agonist

OBJECTIVES

Idiopathic central precocious puberty and its postponement with a (gonadotropin-releasing hormone) GnRH agonist are complex conditions, the final effects of which on bone mass are difficult to define. We evaluated bone mass, body composition, and bone remodeling in two groups of girls with idiopathic central precocious puberty, namely one group that was assessed at diagnosis and a second group that was assessed three years after GnRH agonist treatment.

METHODS

The precocious puberty diagnosis and precocious puberty treatment groups consisted of 12 girls matched for age and weight to corresponding control groups of 12 (CD) and 14 (CT) girls, respectively. Bone mineral density and body composition were assessed by dual X-ray absorptiometry. Lumbar spine bone mineral density was estimated after correction for bone age and the mathematical calculation of volumetric bone mineral density. CONEP: CAAE-0311.0.004.000-06.

RESULTS

Lumbar spine bone mineral density was slightly increased in individuals diagnosed with precocious puberty compared with controls; however, after correction for bone age, this tendency disappeared (CD = -0.74 + 0.9 vs. precocious puberty diagnosis = -1.73 + 1.2). The bone mineral density values of girls in the precocious puberty treatment group did not differ from those observed in the CT group.

CONCLUSION

There is an increase in bone mineral density in girls diagnosed with idiopathic central precocious puberty. Our data indicate that the increase in bone mineral density in girls with idiopathic central precocious puberty is insufficient to compensate for the marked advancement in bone age observed at diagnosis. GnRH agonist treatment seems to have no detrimental effect on bone mineral density.

Association between passive smoking in adulthood and phalangeal bone mineral density: results from the KRAM study--the Danish Health Examination Survey 2007-2008

The study investigates an association between phalangeal bone mineral density (BMD) and self-reported passive smoking using data on 15,038 persons (aged 18-95 years), who underwent a BMD scan in the Danish KRAM study. BMD was significantly lower in persons exposed to long-term passive smoking in their home during adulthood.

INTRODUCTION

Smoking is associated with decreased bone mineral density (BMD) and increased risk of osteoporotic fractures. This study aimed to investigate a possible association between BMD at the phalangeal bones and self-reported passive smoking.

METHODS

The study included a cohort of 15,544 men and women aged 18-95 years, who underwent a BMD scan in the Danish KRAM study. BMD scans of the middle phalanges of the second, third and fourth digits of the non-dominant hand were performed with a compact radiographic absorptiometry system (Alara MetriScan®). Also, height, weight and body fat percentage were measured and 96.7% (n = 15,038) of the participants answered a self-reported questionnaire with information on passive smoking, other lifestyle factors, education, etc. The association between passive smoking and BMD was examined using multiple linear regression analysis.

RESULTS

A total of 39.1% (n = 5,829) of the participants had been exposed to passive smoking in adulthood at home. BMD was significantly lower in subjects exposed to passive smoking, 0.343 vs. 0.331 g/cm(2); p < 0.01 (unadjusted) and 0.339 vs. 0.337 g/cm(2); p < 0.05 (adjusted for age, gender, height and weight, and smoking). Multiple linear regression analysis showed that exposure to passive smoking for more than 20 years in adulthood at home was significantly related to BMD when adjusted for potential confounders (men, β = -4.4 × 10(-3); r = -0.05; p < 0.01 and women, β = -2.3 × 10 (-3); r = -0.03; p < 0.05). This relationship was also seen in the group of never smokers (β = -3.3 × 10(-3); r = -0.03; p = 0.01).

CONCLUSION

Our study supports a potential negative effect of long-term passive smoking in adulthood at home on phalangeal BMD.

Childhood-onset disease carries a higher risk of low bone mineral density in an adult population of systemic lupus erythematosus

OBJECTIVE

To study the BMD of patients with SLE according to the age of disease onset.

METHODS

Consecutive SLE patients were screened for BMD at the hip, lumbar spine and whole body by the dual-energy X-ray absorptiometry (DXA). Comparison was made between patients who had disease onset in childhood (<18 years) and adulthood (≥18 years). Factors associated with low BMD were studied by linear regression.

RESULTS

A total of 395 SLE patients were studied (94% women; 11% childhood-onset disease). Osteoporosis of the lumbar spine and the hip/femoral neck was present in 20 and 10% of the patients, respectively. Childhood-onset SLE patients were less likely to be post-menopausal, but had significantly lower BMI, longer SLE duration and a higher frequency of ever use of high-dose CSs, CYC and AZA. Despite a significantly younger age, the BMD of the hip, femoral neck and lumbar spine was significantly lower in childhood- than adult-onset SLE patients. In linear regression models, childhood-onset disease was an independent factor for lower BMD at the lumbar spine (β = -0.18; P = 0.002), hip (β = -0.20; P = 0.001) and femoral neck (β = -0.16; P = 0.01) after adjustment for age, sex, BMI, smoking, menopause, SLE duration and damage index, duration and current dose of prednisolone treatment and the ever use of high-dose glucocorticoids, other immunosuppressive agents, calcium, vitamin D and the bisphosphonates.

CONCLUSIONS

In adult SLE patients, childhood-onset disease carries a higher risk of osteoporosis, which may possibly be related to a higher cumulative dose of glucocorticoids used for more active disease and failure to achieve a normal peak bone mass during puberty.

Bone mineral density discordance and exploration of one of its causes

Discordances between hip and spine areal density T-score values are common and incompletely understood. In a cohort of 1157 postmenopausal women, discordances of greater than 10% occurred in 91%, with spine bone mineral density (BMD) T-scores significantly less negative than femoral neck (FN) T-scores (p<0.001). However, when T-scores based on bone mineral content (BMC) rather than BMD were used, the mean discordance was not significantly different from 0. This was largely because BMC at the FN had seemingly declined with age less rapidly than had BMD at that site. This can be explained by age-related areal expansion at the hip, which would be missed in the reported BMD output. One consequence is that if BMC-based T-scores are used to classify patients, substantially fewer individuals would have been judged osteoporotic in this cohort (two-thirds fewer for spine and three-fourths fewer for hip).

Effects of sports training & nutrition on bone mineral density in young Indian healthy females

BACKGROUND & OBJECTIVES

Peak bone mass, a major determinant of osteoporosis is influenced by genetic, nutritional, lifestyle and hormonal factors. This study was designed to evaluate the impact of sports training on dietary intake and bone mineral and metabolic parameters in young healthy Indian females.

METHODS

Healthy female college going students (N=186, sportswomen, 90; controls 96) in the age group of 18-21 yr, residing in New Delhi (India) were evaluated for anthropometry, biochemistry (serum total and ionic calcium, phosphorus, total alkaline phosphatase, 25-hydroxyvitamin D & parathyroid hormone), diet, physical activity and lifestyle. Bone mineral density (BMD) at hip, forearm and lumbar spine were studied using central DXA.

RESULTS

Sports related physical activity (3 vs. 0 h/day, P < 0.001) and direct sunlight exposure (120 vs. 30 min/day, P < 0.001) were significantly higher in sportswomen than in controls with sedentary lifestyle. Significantly higher intake of all macronutrients (energy, protein, carbohydrates and fat) and dietary calcium was noted in the diets of sportswomen. Mean serum 25(OH)D levels were significantly higher (53.0 ± 18.9 vs. 12.9 ± 7.7 nmol/l; P < 0.001) while PTH (35.3 ± 17.6 vs. 51.7 ± 44.9 pg/ml; P < 0.001) and ALP levels (194.0 ± 51.0 vs. 222.1 ± 51.4 IU/l; P<0.001) were significantly lower in sportswomen when compared to controls. No significant difference was found in ionized calcium and inorganic phosphorus in the two groups. Significantly higher (P < 0.001) total BMD and BMD at all sites except femur neck were found in sportswomen than controls (P < 0.001).

INTERPRETATION & CONCLUSIONS

Physical activity, optimal nutrition and adequate sun exposure are vital for attaining peak bone mass.

Consumption of different sources of omega-3 polyunsaturated fatty acids by growing female rats affects long bone mass and microarchitecture

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) consumption has been reported to improve bone health. However, sources of ω-3 PUFAs differ in the type of fatty acids and structural form. The study objective was to determine the effect of various ω-3 PUFAs sources on bone during growth. Young (age 28d) female Sprague-Dawley rats were randomly assigned (n=10/group) to a high fat 12% (wt) diet consisting of either corn oil (CO) or ω-3 PUFA rich, flaxseed (FO), krill (KO), menhaden (MO), salmon (SO) or tuna (TO) for 8 weeks. Bone mass was assessed by dual-energy X-ray absorptiometry (DXA) and bone microarchitecture by micro-computed tomography (μCT). Bone turnover markers were measured by enzyme immunoassay. Lipid peroxidation was measured by calorimetric assays. Results showed that rats fed TO, rich in docosahexaenoic acid (DHA, 22:6ω-3) had higher (P<0.009) tibial bone mineral density (BMD) and bone mineral content (BMC) and lower (P=0.05) lipid peroxidation compared to the CO-fed rats. Reduced lipid peroxidation was associated with increased tibial BMD (r2=0.08, P=0.02) and BMC (r2=0.71, P=0.01). On the other hand, rats fed FO or MO, rich in alpha-linolenic acid (ALA, 18:3ω-3), improved bone microarchitecture compared to rats fed CO or SO. Serum osteocalcin was higher (P=0.03) in rats fed FO compared to rats fed SO. Serum osteocalcin was associated with improved trabecular bone microarchitecture. The animal study results suggest consuming a variety of ω-3 PUFA sources to promote bone health during the growth stage.

Premenopausal osteoporosis: how to treat?

There is no agreement in defining osteoporosis in premenopausal women and diagnosis must be done carefully and not based on densitometric parameters. One must take into account the presence of other risk factors and history of fragility fractures, diseases or drugs that cause bone loss. Over 50% of premenopausal women with osteoporosis will have a secondary cause, with the remainder diagnosed with idiopathic osteoporosis. Therapeutic considerations are limited by a few studies in this group of patients, especially in regard to the risk of fractures. On the other hand, the FRAX index cannot be applied to premenopausal women. This article will review the measures to apply depending on the type of premenopausal osteoporosis, based on current scientific evidence.

Does the cortical bone resorption rate change due to 90Sr-radiation exposure? Analysis of data from Techa Riverside residents

The Mayak Production Association released large amounts of (90)Sr into the Techa River (Southern Urals, Russia) with peak amounts in 1950-1951. Techa Riverside residents ingested an average of about 3,000 kBq of (90)Sr. The (90)Sr-body burden of approximately 15,000 individuals has been measured in the Urals Research Center for Radiation Medicine in 1974-1997 with use of a special whole-body counter (WBC). Strontium-90 had mainly deposited in the cortical part of the skeleton by 25 years following intake, and (90)Sr elimination occurs as a result of cortical bone resorption. The effect of (90)Sr-radiation exposure on the rate of cortical bone resorption was studied. Data on 2,022 WBC measurements were selected for 207 adult persons, who were measured three or more times before they were 50-55 years old. The individual-resorption rates were calculated with the rate of strontium recirculation evaluated as 0.0018 year(-1). Individual absorbed doses in red bone marrow (RBM) and bone surface (BS) were also calculated. Statistically significant negative relationships of cortical bone resorption rate were discovered related to (90)Sr-body burden and dose absorbed in the RBM or the BS. The response appears to have a threshold of about 1.5-Gy RBM dose. The radiation-induced decrease in bone resorption rate may not be significant in terms of health. However, a decrease in bone remodeling rate can be among several causes of an increased level of degenerative dystrophic bone pathology in exposed persons.

Bone mineral accrual from 8 to 30 years of age: an estimation of peak bone mass

Bone area (BA) and bone mineral content (BMC) were measured from childhood to young adulthood at the total body (TB), lumbar spine (LS), total hip (TH), and femoral neck (FN). BA and BMC values were expressed as a percentage of young-adult values to determine if and when values reached a plateau. Data were aligned on biological ages [years from peak height velocity (PHV)] to control for maturity. TB BA increased significantly from -4 to +4 years from PHV, with TB BMC reaching a plateau, on average, 2 years later at +6 years from PHV (equates to 18 and 20 years of age in girls and boys, respectively). LS BA increased significantly from -4 years from PHV to +3 years from PHV, whereas LS BMC increased until +4 from PHV. FN BA increased between -4 and +1 years from PHV, with FN BMC reaching a plateau, on average, 1 year later at +2 years from PHV. In the circumpubertal years (-2 to +2 years from PHV): 39% of the young-adult BMC was accrued at the TB in both males and females; 43% and 46% was accrued in males and females at the LS and TH, respectively; 33% (males and females) was accrued at the FN. In summary, we provide strong evidence that BA plateaus 1 to 2 years earlier than BMC. Depending on the skeletal site, peak bone mass occurs by the end of the second or early in the third decade of life. The data substantiate the importance of the circumpubertal years for accruing bone mineral.

Quantitative ultrasound measurements in premature infants at 1 year of age: the effects of antenatal administered corticosteroids

The aim of this study was to evaluate the effects of antenatally administered glucocorticoids on bone status of preterm infants at 1 year corrected age. The study population consisted of 32 preterm infants with a gestational age of 24-34 weeks. The infants were divided into two groups according to antenatal exposure to corticosteroids. Quantitative ultrasound (QUS) assessment of bone was performed in the study infants at the corrected age of 1 year. Blood levels of carboxy-terminal propeptide of type I procollagen (PICP) and carboxy-terminal telopeptide of type I collagen (ICTP) were measured at birth and at 1 year corrected age. Levels of PICP and ICTP were significantly lower at birth in corticosteroid-exposed neonates (P < 0.05). At corrected age of 12 months ICTP levels remained significantly lower in corticosteroid-exposed infants, but we found no significant difference in levels of the bone-formation marker PICP between corticosteroid-exposed and nonexposed infants. In the majority of participant preterm infants bone speed of sound (SOS) was within age-adjusted normal values of full-term infants. There was no significant difference in bone SOS between exposed and nonexposed infants at corrected age of 12 months. There was no correlation between SOS and levels of bone markers. The results of our study indicate that, despite the suppression of fetal bone turnover at birth in corticosteroid-exposed infants, antenatal glucocorticoid treatment seems to have no long-term impact on bone status of preterm infants assessed by QUS complementary to measurement of bone-turnover markers at 1 year corrected age.

Age at onset of puberty predicts bone mass in young adulthood

OBJECTIVE

To determine whether the commencement and length of puberty influences dual x-ray absorptiometry (DXA) values of bone mineral content (BMC) and bone mineral density (BMD) in the axial and appendicular skeleton at skeletal maturity.

STUDY DESIGN

From the Bone Mineral Density in Childhood Study, we identified children who began puberty and completed sexual and skeletal development and examined whether the timing and length of puberty influence DXA values of BMC and BMD at skeletal maturity.

RESULTS

A total of 78 girls and 85 boys began puberty and completed skeletal maturity; 4.4 ± 0.8 and 4.5 ± 0.8 years later, respectively. Multiple linear regression analyses indicated that the age of onset of puberty was a strong negative predictor of DXA bone measurements at skeletal maturity, independent of bone values at the beginning of puberty, and the length of puberty. This negative relation was observed for all BMC and BMD measurements at all skeletal sites, in both boys and girls (all P < .0001). In contrast, length of puberty had no relation to any measures of bone.

CONCLUSIONS

In healthy adolescent males and females, bone mass and bone density at skeletal maturity are inversely related to the timing of puberty.

Osteopenia in Gaucher disease develops early in life: response to imiglucerase enzyme therapy in children, adolescents and adults

BACKGROUND

In Gaucher disease (GD), acid-β-glucosidase (GBA1) gene mutations result in defective glucocerebrosidase and variable combinations of hematological, visceral, and diverse bone disease. Osteopenia is highly prevalent, but its age of onset during the natural course of GD is not known. It is also unclear if the degree of improvement in osteopenia, secondary to imiglucerase enzyme therapy, differs by the age of the patient.

OBJECTIVE

We hypothesized that osteopenia develops early in life, during the natural course of type 1 Gaucher disease (GD1), and that its response to treatment is maximal during this period.

METHODS

We examined data from the International Collaborative Gaucher Group (ICGG) Gaucher Registry of patients treated with imiglucerase between the ages of 5 and 50 years. Lumbar spine bone mineral density (BMD) (determined by dual-energy X-ray absorptiometry (DXA) and expressed as Z-scores) at baseline and for up to 10 years on imiglucerase were analyzed in children (ages ≥ 5 to <12 years), adolescents (≥ 12 to <20 years), young adults (≥ 20 to < 30 years), and older adults (≥ 30 to < 50 years). BMD was correlated with other disease characteristics. Pre-treatment, descriptive statistics were applied to 5-year age categories. Non-linear mixed effects regression models were used to analyze DXA Z-scores over time after treatment with imiglucerase.

RESULTS

Pre-treatment, low BMD was prevalent in all age groups, most strikingly in adolescents. DXA Z-scores were at or below -1 in 44% of children (n=43), 76% of adolescents (n=41), 54% of young adults (n=56) and 52% of older adults (n=171). The most common GBA1 genotype was N370S heteroallelic. Baseline hematological and visceral manifestations in the 4 age groups were similar. In children with DXA Z-scores ≤-1 at baseline, imiglucerase therapy for 6 years resulted in improvement of mean DXA Z-scores from -1.38 (95% CI -1.73 to -1.03) to -0.73 (95% CI -1.25 to -0.21); in young adults DXA Z-scores improved from -1.95 (95% CI -2.26 to -1.64) to -0.67 (95% CI -1.09 to -0.26). BMD also improved in older adults, but the magnitude of the improvement was lower compared to younger patients.

CONCLUSIONS

Low bone density is common in GD1 with the highest prevalence rate in adolescence, a developmental period critical to attainment of peak bone mass. Imiglucerase results in amelioration of osteopenia in all age groups, with the greatest improvements in younger patients.

Relative importance of body composition, osteoporosis-related behaviors, and parental income on bone speed of sound in adolescent females

INTRODUCTION

Adolescence provides a unique opportunity to employ strategies aimed at optimizing peak bone mass yet there are limited studies on the relationship between specific social constructs, osteoporosis-related behaviors, and bone health status in adolescent females. The purpose of this study was to examine associations between bone speed of sound (SOS) and body composition, osteoporosis-related health behaviors, and parental income in adolescent females.

METHODS

Four hundred forty-two female students in grades 9-12 from schools in Southern Ontario, Canada were measured for height, body mass, and percent body fat and completed a battery of instruments to assess osteoporosis-related health behaviors. Bone SOS was measured by transaxial quantitative ultrasound at the distal radius and midtibia.

RESULTS

Percent body fat was a negative correlate of tibial SOS. No significant correlation was found between physical activity and bone SOS yet physical activity was negatively related to adiposity. Hierarchical regression showed that age and percent body fat were the most important predictors of the variance in tibial SOS scores, with calcium intake having a weaker, yet significant, relationship. Age was the only statistically significant predictor of radial SOS. Users of oral contraceptives had higher radial SOS when controlling for age. Higher parental income was not associated with bone SOS but positive associations between parental income, daily calcium intake, and weekly physical activity were noted.

CONCLUSIONS

Bone SOS is reduced in adolescent females with increased adiposity, whereas it is positively influenced by oral contraceptives and daily calcium intake.

Skeletal integrity and visceral transplantation

Despite continuous improvement in long-term survival, there is no knowledge about risk of bone health impairment and management strategies before and after intestinal transplantation. Therefore, 147 adults were retrospectively studied via chart review; 70 long-term survivors, 53 candidates and 24 recipients with longitudinal follow-up. Evaluation process included measurement of bone mineral density (BMD) and allied biochemical markers. Both long-term survivors and candidates showed low bone mass with lower (p < 0.05) z-scores at hip, femoral neck and spine. Vitamin D deficiency and secondary hyperparathyroidism were observed in both groups. Prevalence of osteoporosis was 44% among long-term survivors and 36% in candidates with age, BMD, duration of parenteral nutrition, type of immunosuppression and rejection being significant risk factors. Fragility fractures occurred at a higher (p = 0.02) rate among long-term survivors (20%) compared to candidates (6%). The longitudinal study documented acceleration (p = 0.025) of bone loss after transplantation with a decline of 13.4% (femoral neck), 12.7% (hip) and 2.1% (spine). Alendronate reduced (p < 0.05) but did not prevent bone loss. In conclusion, intestinal transplant recipients are at risk of osteoporosis secondary to bone loss before and after transplantation. Accordingly, current management includes comprehensive preventive measures with prompt therapeutic intervention utilizing intravenous bisphosphonates or subcutaneous human PTH.

The association of lean mass and fat mass with peak bone mass in young premenopausal women

Total body mass is a major determinant of bone mass, but studies of the relative contributions of lean mass (LM) and fat mass (FM) to bone mass have yielded conflicting results. This is likely because of the use of bone measures that are not adequately adjusted for body size and, therefore, not appropriate for analyses related to body composition, which is also correlated with body size. We examined the relationship between body composition and peak bone mass in premenopausal women aged 18-30 yr using both size-dependent and size-adjusted measures of bone density and body composition, as well as statistical models adjusted for size-related factors. We measured total bone mass and areal bone density using dual-energy X-ray absorptiometry, and used established formulas to calculate estimates of volumetric (size-adjusted) bone density. LM tended to be positively associated with bone both before and after adjustment for size-related factors. FM and body fat percentage, however, were positively associated with size-dependent bone measures, but adjusting for size removed or reversed this association. These findings suggest that the association between bone mass and body composition, especially FM, is dependent on the bone measures analyzed, and that determining the most appropriate size-adjustment techniques is critical for understanding this relationship.

Does childhood and adolescence fracture influence bone mineral content in young adulthood?

Previous fracture may predispose an individual to bone fragility because of impaired bone mineral accrual. The primary objective of the study was to investigate the influence of fractures sustained during childhood and (or) adolescence on total body (TB), lumbar spine (LS), femoral neck (FN), and total hip (TH) bone mineral content (BMC) in young adulthood. It was hypothesized that there would be lower TB, LS, FN, and TH BMC in participants who had sustained a pediatric fracture. Participant anthropometrics, physical activity, and BMC (measured with dual energy X-ray absorptiometry) were assessed longitudinally during childhood and adolescence (from 1991 to 1997), and again in young adulthood (2002 to 2006). Sex, adult height, adult lean mass, adult physical activity, and adolescent BMC adjusted TB, LS, FN, and TH BMC in young adulthood, for those who reported 1 or more fractures (n = 42), were compared with those who reported no fractures (n = 101). There were no significant differences (p > 0.05) in adjusted BMC between fracture and nonfracture groups at the TB, LS, FN, and TH sites in young adulthood. These results suggest that fractures sustained during childhood and adolescence may not interfere with bone mass in young adulthood at clinically relevant bone sites.

Low-dose oral contraceptives in adolescents: how low can you go?

CONTEXT

The use of combined oral contraception (COC) before the accrual of peak bone mass in adolescents is common. Despite the tendency to prescribe lower ethinyl estradiol concentrations so as to reduce thromboembolic complications, concerns have developed as to whether low-dose COC provides sufficient estrogen supplementation for adequate adolescent bone development.

OBJECTIVE

This paper reviews the available literature on bone mineral density (BMD) and low-dose COC in adolescents in an effort to determine whether adult-oriented recommendations for the lowest tolerated estrogen dose should apply to adolescent populations.

DESIGN

A MEDLINE search of all English-language literature (1966 to January 2008) was performed using the terms "adolescent," "oral contraception," and "BMD." Bibliographies were reviewed to extract additional relevant sources. Articles were selected based on pertinence to BMD changes in association with low-dose (20 microg ethinyl estradiol) hormonal contraception with emphasis on adolescent study groups.

RESULTS

A limited number of studies examining 20-microg preparations in adolescents have demonstrated a significantly smaller mean percentage BMD acquisition in COC groups vs untreated controls. Bone mineral density decreases appeared to positively correlate with early gynecological age of first COC use and treatment duration.

CONCLUSIONS

Loss of bone mass as a result of hormonal contraceptive use may have serious long-term implications in the adolescent population, who have yet to achieve peak bone density. Both age at first COC use and cumulative estrogen dose appear to be important factors in determining skeletal development in adolescents. Further studies are warranted to inform specific prescribing practices for this population.

Calcium requirements and metabolism in Chinese-American boys and girls

Calcium requirements of North American adolescents were set at 1300 mg/day based on data from white girls. Calcium requirements for Asian-American adolescents have not been studied. Using metabolic balance protocols and a range in calcium intakes, skeletal calcium retention was determined in Chinese-American adolescents. A sample of 29 adolescents, 15 boys aged 12 to 15 years and 14 girls aged 11 to 15 years, was studied twice on paired calcium intakes ranging between 629 to 1835 mg/day using a randomized-order crossover design. Calcium absorption and bone turnover rates using double-stable calcium isotope kinetic analysis on two calcium intakes per subject were measured and compared in boys and girls. Girls and boys had low habitual mean calcium intakes of 648 and 666 mg/day, respectively, and low mean serum 25-hydroxyvitamin D concentrations of 19.1 and 22.2 ng/mL, respectively. True fractional calcium absorption varied inversely with calcium load. Boys had significantly higher bone turnover rate than girls at the same calcium intake. Calcium retention increased with calcium intake; calcium intakes to achieve maximal calcium retention were 1100 mg/day in boys and 970 mg/day in girls. Recommendations for calcium requirements should be lowered for Chinese-American adolescents.

Bone status of adolescent girls in Pune (India) compared to age-matched South Asian and white Caucasian girls in the UK

Underprivileged adolescent girls in Pune, India, were shorter and lighter, and had reduced lean body mass (LBM) compared with relatively 'well off' age-matched South Asian and white Caucasian girls in the UK. Pune girls had low bone mass for projected bone area (BA) in comparison to their UK counterparts, but they had the appropriate amount of bone mineral content (BMC) for their LBM.

PURPOSE

To determine whether adolescent girls from a low socioeconomic group in Pune, India, who had low dietary calcium intake (449 mg/day; range 356-538 mg/day) and hypovitaminosis D (median serum 25-hydroxyvitamin D 23.4 nmol/l; range 13.5-31.9 nmol/l), would have lower lumbar spine (LS) bone mineral apparent density (BMAD), and total body (TB) BMC adjusted for LBM.

METHODS

Dual energy X-ray absorptiometry was used to measure TB and LS BMC, BA and TB LBM in 50 postmenarcheal girls in Pune. These variables were compared with data from 34 South Asian and 82 white Caucasian age-matched girls in the UK.

RESULTS

Pune girls were shorter and lighter, and had less LBM for height, compared to both UK groups, and they had later age of menarche than UK Asians. BA-adjusted TB BMC and LS BMAD were lower in Pune girls (mean+/-SE 1,778+/-17 g; 0.332+/-0.005 g/cm(3)), compared to the UK South Asians (mean+/-SE 1,864+/-18 g; 0.355+/-0.006 g/cm(3)) and UK white Caucasians (mean+/-SE 1,864+/-13 g; 0.345+/-0.004 g/cm(3)). In contrast both LS and TB BMC adjusted for TB LBM were not significantly different between the groups.

CONCLUSION

Pune girls had low bone mass for projected BA relative to UK South Asian and white Caucasian girls, but had the appropriate amount of BMC for their LBM.

Vitamin D and bone health: potential mechanisms

Osteoporosis is associated with increased morbidity, mortality and significant economic and health costs. Vitamin D is a secosteriod hormone essential for calcium absorption and bone mineralization which is positively associated with bone mineral density [BMD]. It is well-established that prolonged and severe vitamin D deficiency leads to rickets in children and osteomalacia in adults. Sub-optimal vitamin D status has been reported in many populations but it is a particular concern in older people; thus there is clearly a need for effective strategies to optimise bone health. A number of recent studies have suggested that the role of vitamin D in preventing fractures may be via its mediating effects on muscle function (a defect in muscle function is one of the classical signs of rickets) and inflammation. Studies have demonstrated that vitamin D supplementation can improve muscle strength which in turn contributes to a decrease in incidence of falls, one of the largest contributors to fracture incidence. Osteoporosis is often considered to be an inflammatory condition and pro-inflammatory cytokines have been associated with increased bone metabolism. The immunoregulatory mechanisms of vitamin D may thus modulate the effect of these cytokines on bone health and subsequent fracture risk. Vitamin D, therefore, may influence fracture risk via a number of different mechanisms.

Status of bone mineral content and body composition in boys engaged in intensive physical activity

BACKGROUND/AIM

It is well known that physical activity has an anabolic effect on bone tissue. But there is a lack of information about the effect of intensive physical activity in childhood, particularly at the prepubertal stage. To examine the influence of training on body composition and bone mineral density we have studied a group of prepubertal soccer players as well as a group of inactive prepubertal boys at the starting phase of their peak bone mass acquisition.

METHODS

A total of 62 healthy prepubertal boys took part in this study. They were divided into two groups. The first one consisted of 32 soccer players (aged 10.7 +/- 0.5 years), who had been playing football for at least 1 year (10-15 h per week). The second group a control group 30 boys (aged 11.2 +/- 0.7 years) doing 1.5 h per week physical activity at school. Body composition was assessed by a Body Fat Analyzer "BES 200 Z". Bone mineral density measurements of the left and the right calcaneus were done by using ultrasound densitometer "Sahara" (Hologic, Inc., MA, USA).

RESULTS

There were significant differences between soccer players and the control group in fat mass (p = 0.01). Besides, a significant difference was determined between the group of athletes and the control group in bone mineral density of both calcaneal bones (p = 0.01).

CONCLUSION

The results of this study confirm the significant effects of physical activity on reducing body mass and increasing bone density. Considering that football training can be very easily implemented in the broader population of children and young people, which does not apply to many other sports, it should be used more in the prevention of obesity and osteoporosis.

Long-term cereal-based nutritional supplementation improved the total spine bone mineral density amongst Sri Lankan preschool children: a randomized controlled study

BACKGROUND

The Thriposha programme in Sri Lanka provides a combination of energy, protein and micronutrients as a 'ready-to-eat' cereal-based food.

OBJECTIVE

To assess the effectiveness of calcium and vitamin D3 in the Thriposha on bone mineralization among preschool children aged 3-5 years.

DESIGN

Subjects (n = 30) were fed with conventional Thriposha while the control group (n = 30) children were fed without mineral and vitamin premix (Corn-Soya-Blend - CSB) for a period of nine months. Dual-energy X-ray absorptiometry (DXA) of total spine was measured at the baseline and after the intervention.

RESULTS

The mean baseline total spine BMD was 0.464 (0.050) g/cm2 in the interventional group and 0.453 (0.035) g/cm2 in the control group (p = 0.09). At the end of the study, the BMD levels were 0.487 (0.047) and 0.454 (0.031) g/cm2 (p < 0.001) respectively.

CONCLUSION

Daily supplementation of cereal based food supplement over a period of nine months improved the total spine BMD.

Sugar-Sweetened Beverages: General and Oral Health Hazards in Children and Adolescents

Ubiquitously unhealthy eating and drinking habits and the development of multiple morbidities, including obesity, type-2 diabetes, dental caries and dental erosion have become a major challenge for physicians, dentists and parents. Modernization has provided heaps of option for outdoor eating and sugar-containing drinks. Even the “diet” labeled drinks are considered not free from sugars and enhances calorie input. With the increasing trends of eating unhealthy, sticky and readily available, refined carbohydrate-rich foods and drinks, problems pertaining to body’s metabolic activity and oral health have also been significantly recognized. Dentists and pediatricians can play a pivotal role and should emphasize on patients’ education and counseling on the proper nutritional diet and health.

Growth hormone: health considerations beyond height gain

The therapeutic benefit of growth hormone (GH) therapy in improving height in short children is widely recognized; however, GH therapy is associated with other metabolic actions that may be of benefit in these children. Beneficial effects of GH on body composition have been documented in several different patient populations as well as improvements in lipid profile. Marked augmentation of bone mineral density also seems evident in many pediatric populations. Some of these benefits may require continued therapy past the acquisition of adult height. With long-term therapy of any kind, the adverse consequences of treatment should also be considered. Fortunately, long-term GH treatment seems to be safe and well-tolerated. This review describes the long-term metabolic effects of GH treatment in the pediatric population and considers how these may benefit children who are treated with GH.

Reference values for vertebral shape in young Chinese women: implication for assessment of vertebral deformity

The race- and sex-specific reference values for vertebral shape are important to determine the prevalence of osteoporotic vertebral fracture. However, these reference values are absent in Chinese women. In the present study, the anterior, middle and posterior heights and the ratios of these heights were measured from 14 vertebral bodies (T4-L5) in 60 premenopausal Chinese women (aged 19-25 years). Cutoff values were set as standard deviations (3 and 3.5 SD) and percentages (15 and 20%) below the means of vertebral height (VH) ratios to define vertebral deformities. The number of subjects with a VH ratio lower than -15% cutoff were significantly more than those with a VH ratio lower than -3 SD cutoff (p < 0.05), but this difference did not occur when a -20% cutoff was selected. A few VH ratios were distributed below -20% and -3 SD cutoffs, and none was below -3.5 SD. The vertebral shape defined by VH ratios was different between Chinese and European women. We conclude that 3.5 SD below the reference mean is an ideal cutoff value for the definition of prevalent vertebral fractures in Chinese women, and reference data should be obtained from young premenopausal women.

Peak bone mineral density, lean body mass and fractures

BACKGROUND

During childhood and adolescence, bone mass and lean body mass (LBM) increase till a plateau is reached. In this longitudinal and cross-sectional study, the age of reaching the plateau was evaluated for lumbar spine and total body bone mass measurements and lean body mass. The association between fractures and bone mineral density (BMD) was studied.

PATIENTS AND METHODS

We included 501 healthy participants, 141 males and 360 females, aged 13-29 years. Of these 90 had participated in a previous longitudinal study of 444 participants, aged 4-20 years (for the first measurement) and 198 participants, aged 8-25 years (for a second measurement). BMD and body composition were measured with dual energy X-ray absorptiometry (DXA). Volumetric BMD (bone mineral apparent density, BMAD) was calculated. All the data were used to determine the age of reaching the plateau.

RESULTS

The plateau for lumbar spine BMD, BMAD, total body BMD, bone mineral content and LBM was reached between 18 and 20 years of age in females and between 18 and 23 years in males. The prevalence of fractures was 37% in males and 28% in females. Total body BMD Z-score was significantly lower in all participants who had had a fracture (p<0.05), whereas lumbar spine BMD and BMAD was only significantly lower in females who had had fractures (p=0.007 and p<0.001, respectively). Mean lumbar spine BMAD Z-score at the previous measurement was significantly lower in the participants who had a first fracture between the last two measurements (p=0.04).

CONCLUSION

Peak BMD and peak LBM were attained between 18 and 20 years in females and between 18 and 23 years in males in this study using longitudinal and cross sectional data in the age range of 4 to 30 years. A significantly lower total body BMD was seen in participants who had had a fracture and a lower lumbar spine BMD and BMAD in females who had had a fracture. Lumbar spine BMAD Z-score seems to be a good predictor for future fractures.

Age curves of bone mineral density at the distal radius and calcaneus in Koreans

This study evaluated age-related changes in bone mineral density (BMD) and identified the peak bone mineral density (PBMD) in Koreans. We recruited 2929 subjects, ranging in age from 5 to 86 years, from three regions: Seoul, Siwha, and Gwangyang. The BMD at the distal radius and calcaneus were measured with dual-energy X-ray absorptiometry, and anthropometric measures were also obtained. PBMD was calculated from the highest mean in each age group. The PBMD at the distal radius was 0.514 +/- 0.06 g/cm(2) in females and 0.598 +/- 0.07 g/cm(2) in males. Peak ages for both sexes were the thirties. For the calcaneus, PBMD was 0.509 +/- 0.09 g/cm(2) in females and 0.629 +/- 0.09 g/cm(2) in males. Peak ages were the thirties for females and the twenties for males. These results could facilitate international or interracial comparisons and be used as reference data to screen for osteoporosis in Koreans.

Factors affecting calcium balance in Chinese adolescents

Chinese dietary reference intakes (DRIs) for calcium were developed mainly from studies conducted amongst Caucasians, yet a recent review showed that reference calcium intakes for Asians are likely to be different from those of Caucasians (Lee and Jiang, 2008). In order to develop calcium DRIs for Chinese adolescents, it is necessary to explore the characteristics and potential influencing factors of calcium metabolic balance in Chinese adolescents. A total of 80 students (15.1+/-0.8 years) were recruited stratified by gender from a 1-year calcium supplementation study. Subjects were randomly designed to four groups and supplemented with calcium carbonate tablets providing elemental calcium at 63, 354, 660, and 966 mg/day, respectively. Subjects consumed food from a 3-day cycle menu prepared by staff for 10 days. Elemental calcium in samples of foods, feces, and urine was determined in duplicates by inductively coupled plasma atomic emission spectrometry. The total calcium intake ranged from 352 to 1323 mg/day. The calcium apparent absorption efficiency and retention in boys were significantly higher than that in girls (68.7% vs. 46.4%, 480 mg/day vs. 204 mg/day, P<0.05). Calcium retention increased with calcium intakes, but did not reach a plateau. Calcium absorption efficiency in boys increased with calcium intake up to 665 mg/day, and decreased after that. In girls, calcium absorption efficiency decreased with calcium intake. Calcium absorption efficiency increased within 1 year after first spermatorrhea in boys, but decreased with pubertal development in girls. Sex, calcium intake, age, and pubertal development were the most important determinants of calcium absorption (R(2)=0.508, P<0.01) and retention (R(2)=0.745, P<0.05). This study indicates that sex, calcium intake, age, and pubertal development are important factors for calcium retention and absorption during growth, which should be considered for the development of calcium DRIs for Chinese adolescents.

Low bone mineral density in children and adolescents with inflammatory bowel disease: a population-based study from Western Sweden

BACKGROUND

Low bone mineral density (BMD) has been recognized as a potential problem in children with inflammatory bowel disease (IBD). The aim of the study was to investigate BMD in Swedish children and adolescents with IBD and to evaluate possible factors affecting BMD.

METHODS

To evaluate BMD, all patients (n = 144) underwent a dual-energy X-ray absorptiometry (DXA) of the whole body and the spine. BMD values were expressed as Z-scores using normative pediatric data from Lunar (GE Medical Systems).

RESULTS

In this population-based study, the lowest BMD values were found in the lumbar spine. The entire IBD group showed significantly lower BMD Z-scores of the lumbar spine (L2-L4) in comparison to healthy references (-0.8 standard deviation [SD], range -5.9 to 3.7 SD, P < 0.001). Decreased BMD with a Z-score < -1 SD occurred in 46.7% of the individuals with Crohn's disease (CD) and in 47.0% of those with ulcerative colitis (UC). Low BMD with a Z-score ≤ -2 SD was present in 26.7% of the patients with CD and in 24.1% of the UC patients. In a multiple regression model with BMD lumbar spine as the depending variable, possible factors associated with lower BMD were male gender, low body mass index (BMI), and treatment with azathioprine.

CONCLUSIONS

Low BMD is prevalent in Swedish pediatric patients with IBD. Possible risk factors for lower BMD are male gender, low BMI, and treatment with azathioprine, as a probable marker of disease course severity.