Total Body Body Bone Mineral Content Research Articles

Bone health and physical activity in adolescents with juvenile idiopathic arthritis: a cross-sectional case-control study

BackgroundAdolescents with juvenile idiopathic arthritis (JIA) tend to engage in less physical activity than their typically developing peers. Physical activity is essential for bone development and reduced physical activity may detrimentally effect bone health. Thus, we examined differences in total body bone mineral content (BMC) and areal bone mineral density (aBMD) between adolescents with JIA and adolescent controls without JIA. We also examined associations between moderate-to-vigorous physical activity (MVPA), lean mass, and bone outcomes.MethodsParticipants included 21 adolescents with JIA (14 females, 7 males) and 21 sex- and age-matched controls aged 10–20 years. Assessments included: height; weight; triple-single-leg-hop distance (TSLH); MVPA by accelerometry; and total body BMC, aBMD, and lean mass measured using dual X-ray absorptiometry. Height-adjusted z-scores were calculated for BMC and aBMD and used for all analyses. Multiple linear mixed effects models examined group differences in BMC and aBMD, adjusting for sex, maturity, MVPA, TSLH, and lean mass. Participants clusters, based on sex and age (within 18 months), were considered random effects.ResultsAdolescents with JIA had lower total body aBMD z-scores [β (95% CI); -0.58 (-1.10 to -0.07), p = 0.03] and BMC z-scores [-0.47 (-0.91 to -0.03), p = 0.04] compared with controls. Mean daily MVPA was 22.0 min/day lower in adolescents with JIA than controls; however, MVPA was not associated with aBMD [-0.01 (-0.01 to 0.01), p = 0.32] or BMC [0.00 (-0.01 to 0.00), p = 0.39]. Lean mass was positively associated with aBMD [0.05 (0.01 to 0.09) g/cm2, p = 0.03] and BMC [0.06 (0.03 to 0.10) g, p < 0.001].ConclusionAdolescents with JIA had lower total body aBMD and BMC compared with sex- and age-matched controls without JIA. Group differences in bone outcomes were not associated with the lower MVPA participation of adolescents with JIA. Despite this, physical activity should still be encouraged as it promotes physical well-being.

Small animal DXA instrument comparison and validation

Several new peripheral dual-energy X-ray absorptiometry (DXA) devices designed for assessment of bone and body composition in rodents have been developed. We compared the performance (accuracy and precision) of two of these devices, the InAlyzer and the iNSiGHT, to those of an established device, the PIXImus. We measured total body bone mineral content (BMC), bone mineral density (BMD), and body composition (lean and fat mass) on the three DXA devices in 18 male C57Bl/6 J mice (6 each of ages 8, 14, and 24 weeks, weighing 22 to 33 g). DXA body composition measures were compared to whole-body nuclear magnetic resonance (NMR) outcomes. BMC of the femur was also compared to ex vivo micro-computed tomography (microCT). Total body BMD from the InAlyzer and iNSiGHT devices was strongly correlated to that from PIXImus (R2 = 0.83 and 0.82, respectively), but was ~25 % higher than PIXImus. Total body BMC measures by InAlyzer were strongly associated with those from PIXImus (R2 = 0.86), whereas those from iNSiGHT were only weakly correlated (R2 = 0.29). Femur BMC from InAlyzer was strongly correlated with microCT outcomes, whereas iNSiGHT was only weakly correlated. InAlyzer and iNSiGHT fat mass measures were very strongly correlated with PIXImus and NMR outcomes (R2 = 0.91 to 0.97), with slightly weaker associations for lean mass (R2 = 0.81 to 0.76). Short-term precision of InAlyzer and iNSiGHT measurements were excellent, and akin to those from the PIXImus for both body composition and bone measures, ranging between 0.39 and 3.2 %. With faster scan times, closed X-ray source and excellent precision, the new devices are both satisfactory replacements for the now discontinued PIXImus system. However, given the accuracy of the bone and body composition measures, the InAlyzer may be preferable for studies where musculoskeletal changes are the main interest.

Whole – body vibration training for children with neurological disabilities

Background. Over the years, the concern over bone health deterioration in children with Neurological Disabilities (ND) has caught the interest of the research community. As the current traditional exercise methods are considered too challenging for children with ND, it is essential to seek effective rehabilitation programs with minimum difficulties and movement restrictions for children with disabilities, ultimately improving their muscle and bone health. Therefore, this study was performed to evaluate the potential application of Whole-body Vibration Training (WBVT) as a beneficial and effective approach to improving Bone Mineral Density (BMD), total body Bone Mineral Content (BMC), and lean mass in children with ND. Methodology. The impact of WBVT on children with ND was investigated using a systematic review and meta-analysis approach following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A database search was conducted to screen and select past literature sources that were published from January 2002 to July 2022 from EBSCO, PubMed, Scopus, and Web of Science databases and met the inclusion and exclusion criteria. Following the quality assessment (PEDro scale and NIH scale) and sensitivity analysis, the Standardised Mean Difference (SMD) was conducted using the STATA 15.1 software with a 95% Confidence interval (95% CI). (PROSPERO registration number: CRD42022343789). Results. Eight studies (four Randomised Controlled Trial (RCT) and four non-RCT studies) were selected, which involved 184 male and 130 female participants. Based on the PEDro scale, all RCT studies were classified as high methodological quality, while the NIH scale rated all non-RCT papers as "Good". In addition, the meta-analysis results indicated that WBVT substantially enhanced femur BMD [(P ＜ 0.01, z = 3.37), SMD (95% CI) = 0.47 (0.20, 0.74)], lumbar spine BMD [(P = 0.02, z = 2.32), SMD (95% CI) = 0.32 (0.05, 0.58)], total body BMC [(P ＜ 0.01, z = 3.42), SMD (95% CI) = 0.29 (0.12, 0.46)] and lean mass [(P ＜ 0.01, z = 2.80), SMD (95% CI) = 0.25 (0.07, 0.42)] of children with ND. However, the effect of WBVT was insignificant on the total body BMD of children with ND [(P = 0.22, z = 1.24), SMD (95% CI) = 0.14 (-0.08, 0.37)]. Conclusion. The meta-analysis demonstrated the significant effect of WBVT on the femur BMD, lumbar spine BMD, total body BMC, and lean mass in children with ND. Hence, WBVT can be suggested as a complementary treatment prescription for children with ND.

Six-weeks Of Resistance Training Is Not Sufficient To Stimulate Bone Response In Older Adults

Aging presents a variety of challenges, ranging from loss of muscle mass, strength, and bone density to functional impairment, risk of fall and fracture. Resistance exercise is known to load the bone and enhance bone density and subsequently strength. However these adaptation typically occur over a long period of time (6+ months). PURPOSE: The purpose of this study was to evaluate whether either dumbbell or elastic band resistance training are beneficial in bone morphology of older adults over 6 weeks of training or a control period. METHODS: Fifty-seven males and females (mean ± SD; age = 66.5 ± 7.09 yrs; height = 165.2 ± 10.6 cm; body mass = 74.5 ± 14.6 kg) volunteered to participate in this study. Participants underwent a total body dual-energy x-ray absorptiometry (DXA) scan for segmental and total body bone mineral content (BMC) and bone mineral density (BMD). Participants were block randomized into one of three groups: elastic band resistance training (EBRT; n = 24), dumbbell resistance training (DBRT; n = 21), or control (CON; n = 12). EBRT and DBRT were asked to visit the laboratory twice weekly over 6-weeks while CON maintained their daily routine. Three-day dietary recalls were collected to ensure dietary maintenance throughout the intervention period. Data were analyzed using a two-way (time x treatment) repeated measures ANOVA and an alpha pre-determined at 0.05. RESULTS: Results indicated there was no two-way interaction for total body BMC (p = 0.164) nor was there a main effect for time (p = 0.39) or group (p = 0.40). Likewise, total body BMD indicated no 2-way interaction (p = 0.79) and no main effect for time (p = 0.753). However, there was a main effect for group where collapsed across time, DBRT had a higher BMD than CON (p = 0.05), but no other differences were observed. CONCLUSIONS: These data suggest that either the load provided throughout the training from DBRT and EBRT to stimulate change in bone over 6-weeks was insufficient or the duration was not long enough. Most previous research supports the latter as bone remodeling occurs in a throughout 4-8 month periods. Other factors that may impact the outcome of the stimuli include exogenous pharmacological treatment for bone loss and dietary factors.

Physical Activity for Bone Health: How Much and/or How Hard?

High-impact physical activity is associated with bone health, but higher volumes of lower-intensity activity may also be important. The aims of this study were to: 1) investigate the relative importance of volume and intensity of physical activity accumulated during late adolescence for bone health at age 23 yr; and 2) illustrate interpretation of the results. This is a secondary analysis of data from the Iowa Bone Development Study, a longitudinal study of bone health from childhood through to young adulthood. The volume (average acceleration) and intensity distribution (intensity gradient) of activity at age 17, 19, 21, and 23 yr were calculated from raw acceleration ActiGraph data and averaged across ages. Hip areal bone mineral density (aBMD), total body bone mineral content (BMC), spine aBMD, and hip structural geometry (dual-energy X-ray absorptiometry, Hologic QDR4500A) were assessed at age 23 yr. Valid data, available for 220 participants (124 girls), were analyzed with multiple regression. To elucidate significant effects, we predicted bone outcomes when activity volume and intensity were high (+1SD), medium (mean), and low (-1SD). There were additive associations of volume and intensity with hip aBMD and total body BMC (low-intensity/low-volume cf. high-intensity/high-volume = [INCREMENT]0.082 g·cm and [INCREMENT]169.8 g, respectively). For males only, spine aBMD intensity was associated independently of volume (low-intensity cf. high-intensity = [INCREMENT]0.049 g·cm). For hip structural geometry, volume was associated independently of intensity (low-volume cf. high-volume = [INCREMENT]4.8-6.6%). The activity profile associated with optimal bone outcomes was high in intensity and volume. The variation in bone health across the activity volume and intensity distribution suggests intensity is key for aBMD and BMC, whereas high volumes of lower intensity activity may be beneficial for hip structural geometry.

Effects of Preventive Nutrition Interventions among Adolescents on Health and Nutritional Status in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis.

The objective of this review was to assess the impact of preventive nutrition interventions on health and nutritional status of adolescents aged 10–19 years in low- and middle-income countries (LMICs). We searched the databases until 5 February 2019 without any restrictions on publication, date, language, or publication status. A total of 10 studies (15 papers) including 10,802 participants assessing the impact of micronutrient supplementation/fortification were included in this review. We did not find any study assessing the impact of nutrition education and counseling or macronutrient supplementation among adolescents. Among primary outcomes, we are uncertain of the effect of iron supplementation with or without folic acid on anemia (daily supplementation; relative risk (RR): 1.04, 95% confidence interval (CI) 0.42, 2.57; one study; 1160 participants; low-quality evidence; weekly supplementation; RR: 1.07, 95% CI: 0.46, 2.52; one study; 1247 participants; low-quality evidence). We are also uncertain of the effect of various micronutrient supplementation/fortification on body mass index (BMI) (calcium/vitamin D supplementation; (MD: −0.01 kg/m2; 95% CI: −1.20, 1.17; two studies; 730 participants; I2 94%; very-low-quality evidence, iron supplementation with or without folic acid; MD: 0.47 kg/m2; 95% CI: −0.17, 1.11; two studies; 652 participants; I2 37%; very-low-quality evidence, zinc supplementation; MD: 0.35 kg/m2; 95% CI: −0.15, 0.85; one study; 382 participants; very-low-quality evidence) and multiple micronutrient (MMN) fortification; MD: 0.23 kg/m2, 95% CI: −0.11, 0.57; two studies; 943 participants; I2 22%; very-low-quality evidence). None of the included studies reported any other primary outcomes including morbidity or adverse effects. Among secondary outcomes, iron supplementation with or without folic acid may improve hemoglobin concentrations, and calcium/vitamin D supplementation may improve serum 25(OH)D levels, while calcium only supplementation and calcium and vitamin D supplementation may marginally improve total body bone mineral density (BMD). We are uncertain of the effect of MMN fortification on hemoglobin concentrations, calcium supplementation on total body bone mineral content (BMC), calcium + vitamin D supplementation on total body BMC, and zinc supplementation on zinc levels. There is limited evidence of micronutrient supplementation/fortification among adolescents, especially adolescent boys, on health and nutritional status in LMICs. These findings should be interpreted with caution due to the low quality and limited number of studies.

Fat and Lean Mass Predict Bone Mass During Energy Restriction in Sedentary and Exercising Rodents.

Energy restriction (ER) causes bone loss, but the impact of exercise during ER is less understood. In this study, we examined the impact of metabolic hormones and body composition on both total body bone mineral content (BMC) and local (proximal tibia) volumetric bone mineral density (vBMD) during short- (4 weeks) and long-term (12 weeks) ER with and without exercise in adult female rats. Our first goal was to balance energy between sedentary and exercising groups to determine the impact of exercise during ER. Second, we aimed to determine the strongest predictors of bone outcomes during ER with energy-matched exercising groups.Methods: Female Sprague–Dawley rats were divided into three sedentary groups (ad libitum, –20% ER, and –40% ER) and three exercising groups (ad libitum, –10% ER, and –30% ER). Approximately a 10% increase in energy expenditure was achieved via moderate treadmill running (∼60–100 min 4 days/week) in EX groups. n per group = 25–35. Data were analyzed as a 2 × 3 ANOVA with multiple linear regression to predict bone mass outcomes.Results: At 4 weeks, fat and lean mass and serum insulin-like growth factor-I (IGF-I) predicted total body BMC (R2 = 0.538). Fat mass decreased with ER at all levels, while lean mass was not altered. Serum IGF-I declined in the most severe ER groups (–40 and –30%). At 12 weeks, only fat and lean mass predicted total body BMC (R2 = 0.718). Fat mass declined with ER level regardless of exercise status and lean mass increased due to exercise (+5.6–6.7% vs. energy-matched sedentary groups). At the same time point, BMC declined with ER, but increased with exercise (+7.0–12.5% vs. energy-matched sedentary groups). None of our models predicted vBMD at the proximal tibia at either time point.Conclusion: Both fat and lean mass statistically predicted total body BMC during both short- and long-term ER. Fat and lean mass decreased with ER, while lean mass increased with EX at each energy level. Measures that predicted total body skeletal changes did not predict site-specific changes. These data highlight the importance of maintaining lean mass through exercise during periods of ER.

Variety of activity participation influences leg bone mineral content of pre-pubertal children with developmental coordination disorder

Limited participation in activities in children with developmental coordination disorder (DCD) may have a negative impact on bone mineral accrual. This study aimed to compare bone mineralization and activity participation patterns of pre-pubertal children with DCD and those with typical development, and to determine the relationship between activity participation patterns and bone mineralization in children with DCD. Fifty-two children with DCD (mean age = 7.5 years) and 61 children with typical development (mean age = 7.2 years) participated in the study voluntarily. Appendicular and total body bone mineral content (BMC) and bone mineral density (BMD) were assessed by a whole-body dual-energy X-ray absorptiometry scan. Activity participation patterns were assessed using the Children's assessment of participation and enjoyment (CAPE). Children with DCD had lower appendicular and total body BMCs and BMDs than children with typical development ( P < 0.05). Additionally, they had lower CAPE total activity and physical activity diversity and intensity scores ( P < 0.05). After accounting for the effects of bone age, sex, lean mass and fat mass, the total activity diversity score remained independently associated with leg BMC in children with DCD, explaining 5.5% of the variance ( P < 0.001). However, the physical activity diversity score was no longer associated with leg BMC ( P = 0.084). Diversity (variety) and intensity of activity participation and bone mineralization were lower in pre-pubertal children with DCD. Decreased total activity participation variety was a contributing factor to lower BMC in the legs of children with DCD.

Obesity and type 2 diabetes, not a diet high in fat, sucrose, and cholesterol, negatively impacts bone outcomes in the hyperphagic Otsuka Long Evans Tokushima Fatty rat

BackgroundObesity and type 2 diabetes (T2D) increase fracture risk; however, the association between obesity/T2D may be confounded by consumption of a diet high in fat, sucrose, and cholesterol (HFSC). ObjectiveThe study objective was to determine the main and interactive effects of obesity/T2D and a HFSC diet on bone outcomes using hyperphagic Otuska Long Evans Tokushima Fatty (OLETF) rats and normophagic Long Evans Tokushima Otsuka (LETO) controls. MethodsAt 8weeks of age, male OLETF and LETO rats were randomized to either a control (CON, 10 en% from fat as soybean oil) or HFSC (45 en% from fat as soybean oil/lard, 17 en% sucrose, and 1wt%) diet, resulting in four treatment groups. At 32weeks, total body bone mineral content (BMC) and density (BMD) and body composition were measured by dual-energy X-ray absorptiometry, followed by euthanasia and collection of blood and tibiae. Bone turnover markers and sclerostin were measured using ELISA. Trabecular microarchitecture of the proximal tibia and geometry of the tibia mid-diaphysis were measured using microcomputed tomography; whole-bone and tissue-level biomechanical properties were evaluated using torsional loading of the tibia. Two-factor ANOVA was used to determine main and interactive effects of diet (CON vs. HFSC) and obesity/T2D (OLETF vs. LETO) on bone outcomes. ResultsHyperphagic OLEFT rats had greater final body mass, body fat, and fasting glucose than normophagic LETO, with no effect of diet. Total body BMC and serum markers of bone formation were decreased, and bone resorption and sclerostin were increased in obese/T2D OLETF rats. Trabecular bone volume and microarchitecture were adversely affected by obesity/T2D, but not diet. Whole-bone and tissue-level biomechanical properties of the tibia were not affected by obesity/T2D; the HFSC diet improved biomechanical properties only in LETO rats. ConclusionsObesity/T2D, regardless of diet, negatively impacted the balance between bone formation and resorption and trabecular bone volume and microarchitecture in OLETF rats.

Exercise initiated after the onset of insulin resistance improves trabecular microarchitecture and cortical bone biomechanics of the tibia in hyperphagic Otsuka Long Evans Tokushima Fatty rats

The present study extends our previous findings that exercise, which prevents the onset of insulin resistance and type 2 diabetes (T2D), also prevents the detrimental effects of T2D on whole-bone and tissue-level strength. Our objective was to determine whether exercise improves bone's structural and material properties if insulin resistance is already present in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat. The OLETF rat is hyperphagic due to a loss-of-function mutation in cholecystokinin-1 receptor (CCK-1 receptor), which leads to progressive obesity, insulin resistance and T2D after the majority of skeletal growth is complete. Because exercise reduces body mass, which is a significant determinant of bone strength, we used a body-mass-matched caloric-restricted control to isolate body-mass-independent effects of exercise on bone. Eight-wk old, male OLETF rats were fed ad libitum until onset of hyperglycemia (20weeks of age), at which time they were randomly assigned to three groups: ad libitum fed, sedentary (O-SED); ad libitum fed, treadmill running (O-EX); or, sedentary, mild caloric restriction to match body mass of O-EX (O-CR). Long-Evans Tokushima Otsuka rats served as the normophagic, normoglycemic controls (L-SED). At 32weeks of age, O-SED rats had T2D as evidenced by hyperglycemia and a significant reduction in fasting insulin compared to OLETFs at 20weeks of age. O-SED rats also had reduced total body bone mineral content (BMC), increased C-terminal telopeptide of type I collagen (CTx)/tartrate resistant acid phosphatase isoform 5b (TRAP5b), decreased N-terminal propeptide of type I procollagen (P1NP), reduced percent cancellous bone volume (BV/TV), trabecular number (Tb.N) and increased trabecular separation (Tb.Sp) and structural model index (SMI) of the proximal tibia compared to L-SED. T2D also adversely affected biomechanical properties of the tibial diaphysis, and serum sclerostin was increased and β-catenin, runt-related transcription factor 2 (Runx2) and insulin-like growth factor-I (IGF-I) protein expression in bone were reduced in O-SED vs. L-SED. O-EX or O-CR had greater total body bone mineral density (BMD) and BMC, and BV/TV, Tb.N, Tb.Sp, and SMI compared to O-SED. O-EX had lower CTx and CR greater P1NP relative to O-SED. O-EX, not O-CR, had greater cortical thickness and area, and improved whole-bone and tissue-level biomechanical properties associated with a 4-fold increase in cortical bone β-catenin protein expression vs. O-SED. In summary, EX or CR initiated after the onset of insulin resistance preserved cancellous bone volume and structure, and EX elicited additional benefits in cortical bone.

Increased Bone Mineral Content During Rapid Weight Gain Therapy in Anorexia Nervosa.

Patients with anorexia nervosa (AN) are at high risk of reduced bone mass. Osteocalcin (OC), a bone formation marker, has been proposed to act as a link between bone and energy metabolism. We investigated how the 3 forms of OC respond during a 12-week intensive nutrition therapy in AN patients, in whom large changes in energy metabolism are expected.Twenty-two female AN patients, mean 20.9 years of age, with a starting mean body mass index (BMI) 15.5 kg/m2 (minimum-maximum) (13.4-17.3 kg/m2) completed the study. Biochemical markers, body composition, bone mass by DXA, and pQCT were assessed. Subjects gained in median 9.9 kg (5.5-17.0 kg), and BMI increased from median 15.4 kg/m2 (13.4-17.3 kg/m2) to 19.0 kg/m2 (16.2-20.6 kg/m2), p<0.0001. Fat mass increased from median 11.4% (4.4-24.8%) to 26.7% (16.9-39.8%). Total OC, carboxylated OC (cOC), undercarboxylated OC (ucOC), and bone-specific alkaline phosphatase (BALP) increased during the study period. No change was observed for the resorption marker carboxy-terminal cross-linking telopeptide of type I collagen (CTX). Total body bone mineral content (BMC) increased, but no changes were found for whole body or lumbar spine bone mineral density. Tibial trabecular density measured by pQCT decreased. Total OC, cOC, and ucOC were not associated with BMI, insulin or body composition parameters. This prospective study demonstrates that all 3 forms of OC (total OC, cOC, ucOC) increase during rapid weight gain. BALP increased while the resorption marker CTX was unchanged, which corroborate with the increased total body BMC.

Effects of a Specialist-Led, School Physical Education Program on Bone Mass, Structure, and Strength in Primary School Children: A 4-Year Cluster Randomized Controlled Trial.

This 4-year cluster randomized controlled trial of 365 boys and 362 girls (mean age 8.1 ± 0.3 years) from grade 2 in 29 primary schools investigated the effects of a specialist-taught physical education (PE) program on bone strength and body composition. All children received 150 min/week of common practice (CP) PE from general classroom teachers but in 13 schools 100 min/week of CP PE was replaced by specialized-led PE (SPE) by teachers who emphasized more vigorous exercise/games combined with static and dynamic postural activities involving muscle strength. Outcome measures assessed in grades 2, 4, and 6 included: total body bone mineral content (BMC), lean mass (LM), and fat mass (FM) by DXA, and radius and tibia (4% and 66% sites) bone structure, volumetric density and strength, and muscle cross-sectional area (CSA) by pQCT. After 4-years, gains in total body BMC, FM, and muscle CSA were similar between the groups in both sexes, but girls in the SPE group experienced a greater gain in total body LM (mean 1.0 kg; 95% CI, 0.2 to 1.9 kg). Compared to CP, girls in the SPE group also had greater gains in cortical area (CoA) and cortical thickness (CoTh) at the mid-tibia (CoA, 5.0% [95% CI, 0.2% to 1.9%]; CoTh, 7.5% [95% CI, 2.4% to 12.6%]) and mid-radius (CoA, 9.3% [95% CI, 3.5% to 15.1%]; CoTh, 14.4% [95% CI, 6.1% to 22.7%]), whereas SPE boys had a 5.2% (95% CI, 0.4% to 10.0%) greater gain in mid-tibia CoTh. These benefits were due to reduced endocortical expansion. There were no significant benefits of SPE on total bone area, cortical density or bone strength at the mid-shaft sites, nor any appreciable effects at the distal skeletal sites. This study indicates that a specialist-led school-based PE program improves cortical bone structure, due to reduced endocortical expansion. This finding challenges the notion that periosteal apposition is the predominant response of bone to loading during the prepubertal and early-pubertal period.

Low bone mineral mass is associated with decreased bone formation and diet in girls with Rett syndrome.

The aim of the present study was to characterize biomarkers of bone turnover and their relation with bone mineral mass in a cross-sectional cohort of girls with Rett syndrome (RTT) and to examine the role of dietary, biochemical, hormonal, and inflammatory factors on bone mineral mass and bone biomarkers in this disorder. Total body bone mineral content (BMC) and bone mineral density (BMD) were determined by dual-energy x-ray absorptiometry. Dietary nutrient intakes were determined from 3-day food records. Biomarkers of bone turnover, bone metabolites, vitamin D metabolites, hormones, and inflammatory markers were measured by standard clinical laboratory methods. Serum osteocalcin, bone alkaline phosphatase, and C-telopeptide showed significant inverse relations with age in the RTT cohort. Mean osteocalcin concentrations were significantly lower and mean bone alkaline phosphatase concentrations were significantly higher for individual age groups in the RTT cohort than mean values for their respective age ranges in the reference population. Significant inverse associations were identified between urinary calcium losses, expressed as calcium:creatinine ratios, and total body BMC and BMD z scores. Dietary protein, calcium, and phosphorus intakes, expressed as a proportion of Dietary Reference Intakes for age and sex, showed significant positive associations with total body BMD z scores. The present study suggests decreased bone formation instead of increased bone resorption may explain in part the deficits in bone mineral mass in RTT and that attention to the adequacy of dietary protein, calcium, and phosphorus intakes may offer an opportunity to improve bone health in RTT.

Maternal Vitamin D Status During Pregnancy and Bone Mass in Offspring at 20 Years of Age: A Prospective Cohort Study

It is uncertain whether the vitamin D status of pregnant women influences bone mass of their children. Cohort studies have yielded conflicting results; none have examined offspring at skeletal maturity. This longitudinal, prospective study investigated the association between maternal vitamin D status and peak bone mass of offspring in 341 mother and offspring pairs in the Western Australian Pregnancy Cohort (Raine) Study. Maternal serum samples collected at 18 weeks gestation were assayed for 25-hydroxyvitamin D (25OHD). Outcomes were total body bone mineral content (BMC) and bone mineral density (BMD) measured by dual-energy X-ray absorptiometry in offspring at 20 years of age. The mean (± SD) maternal serum 25OHD concentration was 57.2 ± 19.2 nmol/L; 132 women (38.7%) were vitamin D-deficient (25OHD <50 nmol/L). After adjustment for season of sample collection, maternal factors, and offspring factors (sex, birth weight, and age, height, lean mass, and fat mass at 20 years), maternal 25OHD concentration was positively associated with total body BMC and BMD in offspring, with a mean difference of 19.2 (95% confidence interval [CI], 5.6-32.7) g for BMC and 4.6 (95% CI, 0.1-9.1) mg/cm(2) for BMD per 10.0 nmol/L of maternal 25OHD. Maternal vitamin D deficiency was associated with 2.7% lower total body BMC (mean ± SE) (2846 ± 20 versus 2924 ± 16 g, p = 0.004) and 1.7% lower total body BMD (1053 ± 7 versus 1071 ± 5 mg/cm(2) , p = 0.043) in the offspring. We conclude that vitamin D deficiency in pregnant women is associated with lower peak bone mass in their children. This may increase fracture risk in the offspring in later life.

Cochrane Review: Vitamin D supplementation for improving bone mineral density in children

AbstractBackgroundResults of randomised controlled trials (RCTs) of vitamin D supplementation to improve bone density in children are inconsistent.ObjectivesTo determine the effectiveness of vitamin D supplementation for improving bone mineral density in children, whether any effect varies by sex, age or pubertal stage, the type or dose of vitamin D given or baseline vitamin D status, and if effects persist after cessation of supplementation.Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL Issue 3, 2009), MEDLINE (1966 to present), EMBASE (1980 to present), CINAHL (1982 to present), AMED (1985 to present) and ISI Web of Science (1945 to present) on 9 August 2009, and we handsearched key journal conference abstracts.Selection criteriaPlacebo‐controlled RCTs of vitamin D supplementation for at least three months in healthy children and adolescents (aged from one month to &lt; 20 years) with bone density outcomes.Data collection and analysisTwo authors screened references for inclusion, assessed risk of bias, and extracted data. We conducted meta‐analyses and calculated standardised mean differences (SMD) of the percent change from baseline in outcomes in treatment and control groups. We performed subgroup analyses by sex, pubertal stage, dose of vitamin D and baseline serum vitamin D and considered these as well as compliance and allocation concealment as possible sources of heterogeneity.Main resultsWe included six RCTs (343 participants receiving placebo and 541 receiving vitamin D) for meta‐analyses. Vitamin D supplementation had no statistically significant effects on total body bone mineral content (BMC), hip bone mineral density (BMD) or forearm BMD. There was a trend to a small effect on lumbar spine BMD (SMD 0.15, 95% CI ‐0.01 to 0.31, P = 0.07). There were no differences in effects between high and low serum vitamin D studies at any site though there was a trend towards a larger effect with low vitamin D for total body BMC (P = 0.09 for difference). In low serum vitamin D studies, significant effects on total body BMC and lumbar spine BMD were approximately equivalent to a 2.6% and 1.7 % percentage point greater change from baseline in the supplemented group.Authors' conclusionsThese results do not support vitamin D supplementation to improve bone density in healthy children with normal vitamin D levels, but suggest that supplementation of deficient children may be clinically useful. Further RCTs in deficient children are needed to confirm this.Plain Language SummaryVitamin D for improving bone density in childrenThis summary of a Cochrane Review, presents what we know from research about the effect of vitamin D supplements on bone density in children.The review shows that in healthy children generally, vitamin D supplementation does not improve bone density at the hip, lumbar spine, forearm or in the body as a whole.Some of the evidence suggests that vitamin D supplements may improve bone density in children who have low levels of vitamin D but this is uncertain.We do not have precise information about side effects and complications but the available information suggests that vitamin D supplements are well tolerated.What is osteoporosis and what is vitamin D?Osteoporosis is a condition where bones are weak, brittle and break easily. The risk of osteoporosis and fractures (breaks) in later life depends on how much bone is built when a child and how much bone is lost when an adult. One way to prevent osteoporosis and fractures in later life is to build stronger bones when young. Vitamin D plays an important role in improving the body's absorption of calcium from food, reducing losses of calcium from the body and getting calcium deposited into to bone to improve the quantity of bone developed. Therefore it is thought that if vitamin D levels in the body are low in childhood, less bone will be developed and that improving vitamin D levels by supplements would result in more bone being developed. Bone density is a major measure of bone strength and the amount of bone mineral present at different sites and so is used to measure the effects of interventions, like vitamin D supplementation, to improve bone health.

An Energy-Dense, Nutrient-Poor Dietary Pattern Is Inversely Associated with Bone Health in Women

Measures of dietary patterns have been increasingly used to capture the complex nature of dietary intake. Few studies have investigated the impact of specific dietary patterns on bone health. Areal bone mineral density (BMD) at the lumbar spine and total hip and total body bone mineral content (BMC) were measured using DXA in Australian women aged 18–65 y (n= 527). Dietary patterns were assessed using a 4-d food diary and factor analysis. Scores were calculated based on the amount of each food consumed in the pattern and the weightings determined by factor analysis. Analysis was conducted using generalized estimating equation methods. Factor analysis revealed 5 dietary patterns. Pattern 1 (high consumption of refined cereals, soft drinks, fried potatoes, sausages and processed meat, vegetable oils, beer, and takeaway foods and low consumption of other vegetables, vegetable dishes, tea, coffee, fruit, wholegrain breads, and breakfast cereals) were significantly inversely associated with total body BMC (g) [β = -15.4 (95% CI -27.4, -3.3), adjusted for age, height, physical activity, smoking, education, energy, and calcium intake]. Pattern 4 (high consumption of legumes, seafood, seeds, nuts, wine, rice and rice dishes, other vegetables, and vegetable dishes and low consumption of bacon and ham) were directly associated with BMD at both sites and total body BMC in adjusted models [BMC (g): β = 15.2 (95% CI 2.84, 27.6), fully adjusted model]. The remaining dietary patterns were not consistently associated with BMD or BMC. This study identified specific dietary patterns associated with BMD and total body BMC among women and provides evidence that will contribute to potential food-based strategies for improving bone health.

Weight regulation and bone mass: a comparison between professional jockeys, elite amateur boxers, and age, gender and BMI matched controls

The aim of this study was to compare bone mass between two groups of jockeys (flat: n=14; national hunt: n=16); boxers (n=14) and age, gender and BMI matched controls (n=14). All subjects underwent dual energy X-ray absorptiometry (DXA) scanning for assessment of bone mass, with measurements made of the total body, vertebra L2-4 and femoral neck. Body composition and the relative contribution of fat and lean mass were extrapolated from the results. Data were analysed in accordance with differences in body composition, in particular, height, lean mass, fat mass and age. Both jockey groups were shown to display lower bone mass than either the boxers or control group at a number of sites including total body bone mineral density (BMD) (1.019±0.06 and 1.17±1.05 vs. 1.26±0.01 and 1.26±0.06gcm(-2) for flat, national hunt, boxer and control, respectively), total body bone mineral content (BMC) less head, L2-4 BMD and femoral neck BMD and BMC (p<0.05). Regression analysis revealed that lean mass and height were the primary predictors of total body BMC, although additional group-specific influences were present which reduced bone mass in the flat jockey group and enhanced it in the boxers (R (2)=0.814). Reduced bone mass in jockeys may be a consequence of reduced energy availability in response to chronic weight restriction and could have particular implications for these athletes in light of the high risk nature of the sport. In contrast, the high intensity, high impact training associated with boxing may have conveyed an osteogenic stimulus on these athletes.

Maternal and paternal relationships with offspring bone mass: response to Harvey et al.

Dear Editor, We thank Harvey et al. for their comment [1] regarding our paper comparing relationships of maternal and paternal smoking during pregnancy with offspring bone measures at age 10 years in the Avon Longitudinal Study of Parents and Children (ALSPAC) [2]. We agree that the associations the authors report of maternal smoking and pre-pregnancy BMI with offspring whole body bone mineral content (BMC) at birth in the Southampton Women’s Survey, without similar paternal effects [1], provide some support for intrauterine influences on fetal bone development. However, we emphasise that in our study we aimed to assess whether any intrauterine effects on bone mineral accrual persist into childhood. The authors refer to differences between maternal and paternal associations in our complete case analysis as potentially representing an intrauterine effect. We point out that in our complete case, as in our multiple imputation analysis, there were similar-sized associations of maternal and paternal smoking with offspring total body BMC, bone area and bone mineral density in confounder-adjusted models; parental differences were apparent only in models for spinal bone outcomes. Furthermore, in both analyses, any associations of maternal smoking with offspring bone measures were positive, and thus in the opposite direction to those found with BMC at birth [1, 3, 4], and completely explained by the child’s height and, in particular, weight. Our findings, therefore, are not consistent with an adverse intrauterine effect of maternal smoking on bone development which persists into later childhood. In our other study referenced by the authors, the positive relationship of maternal BMI with offspring bone mass at age 10 years [5] is consistent with that reported at birth [1]. In our complete case, but not in our multiple imputation analysis, maternal effects were slightly stronger than paternal effects, so an intrauterine influence is plausible. However, detailed analyses suggested that these associations were completely driven by the association of maternal BMI with child’s BMI, rather than direct effects on bone development. Previous studies investigating maternal and paternal–offspring BMI associations have had inconsistent findings [6–9], although similar associations of maternal and paternal BMI with offspring BMI demonstrated in ALSPAC [6] and in the largest study to date [9] give support to our findings from multiple imputation of similarsized parental BMI associations with offspring bone mass. Finally, the authors suggest that maternal smoking status and BMI during/pre-pregnancy will be highly correlated with those post-pregnancy. We would expect that this is also true for fathers, suggesting that effects of parental exposures would be similar unless there was a specific effect of the maternal exposure during the intrauterine period [10]. Furthermore, we do not agree that an association of birth weight with later bone density is proof of an intrauterine effect. Smoking is the strongest environmental determinant of birth weight and strongly related to socioeconomic position (and largely explains the association of socioeconomic position with birth weight [11]); thus, familial socioeconomic position and associated lifestyles would C. Macdonald-Wallis (*) :G. Davey Smith :D. A. Lawlor MRC Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK e-mail: C.Macdonald-Wallis@bristol.ac.uk

Vitamin D supplementation for improving bone mineral density in children

Background: Results of randomised controlled trials (RCTs) of vitamin D supplementation to improve bone density in children are inconsistent. Objectives: To determine the effectiveness of vitamin D supplementation for improving bone mineral density in children, whether any effect varies by sex, age or pubertal stage, the type or dose of vitamin D given or baseline vitamin D status, and if effects persist after cessation of supplementation. Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL Issue 3, 2009), MEDLINE (1966 to present), EMBASE (1980 to present), CINAHL (1982 to present), AMED (1985 to present) and ISI Web of Science (1945 to present) on 9 August 2009, and we handsearched key journal conference abstracts. Selection criteria: Placebo-controlled RCTs of vitamin D supplementation for at least three months in healthy children and adolescents (aged from one month to Data collection and analysis: Two authors screened references for inclusion, assessed risk of bias, and extracted data. We conducted meta-analyses and calculated standardised mean differences (SMD) of the percent change from baseline in outcomes in treatment and control groups. We performed subgroup analyses by sex, pubertal stage, dose of vitamin D and baseline serum vitamin D and considered these as well as compliance and allocation concealment as possible sources of heterogeneity. Main results: We included six RCTs (343 participants receiving placebo and 541 receiving vitamin D) for meta-analyses. Vitamin D supplementation had no statistically significant effects on total body bone mineral content (BMC), hip bone mineral density (BMD) or forearm BMD. There was a trend to a small effect on lumbar spine BMD (SMD 0.15, 95% CI -0.01 to 0.31, P = 0.07). There were no differences in effects between high and low serum vitamin D studies at any site though there was a trend towards a larger effect with low vitamin D for total body BMC (P = 0.09 for difference). In low serum vitamin D studies, significant effects on total body BMC and lumbar spine BMD were approximately equivalent to a 2.6% and 1.7 % percentage point greater change from baseline in the supplemented group. Authors' conclusions: These results do not support vitamin D supplementation to improve bone density in healthy children with normal vitamin D levels, but suggest that supplementation of deficient children may be clinically useful. Further RCTs in deficient children are needed to confirm this. PLAIN LANGUAGE SUMMARY Vitamin D for improving bone density in children This summary of a Cochrane Review, presents what we know from research about the effect of vitamin D supplements on bone density in children. The review shows that in healthy children generally, vitamin D supplementation does not improve bone density at the hip, lumbar spine, forearm or in the body as a whole. Some of the evidence suggests that vitamin D supplements may improve bone density in children who have low levels of vitamin D but this is uncertain. We do not have precise information about side effects and complications but the available information suggests that vitamin D supplements are well tolerated. What is osteoporosis and what is vitamin D? Osteoporosis is a condition where bones are weak, brittle and break easily. The risk of osteoporosis and fractures (breaks) in later life depends on how much bone is built when a child and how much bone is lost when an adult. One way to prevent osteoporosis and fractures in later life is to build stronger bones when young. Vitamin D plays an important role in improving the body's absorption of calcium from food, reducing losses of calcium from the body and getting calcium deposited into to bone to improve the quantity of bone developed. Therefore it is thought that if vitamin D levels in the body are low in childhood, less bone will be developed and that improving vitamin D levels by supplements would result in more bone being developed. Bone density is a major measure of bone strength and the amount of bone mineral present at different sites and so is used to measure the effects of interventions, like vitamin D supplementation, to improve bone health.

Vitamin D supplementation for improving bone mineral density in children

Results of randomised controlled trials (RCTs) of vitamin D supplementation to improve bone density in children are inconsistent. To determine the effectiveness of vitamin D supplementation for improving bone mineral density in children, whether any effect varies by sex, age or pubertal stage, the type or dose of vitamin D given or baseline vitamin D status, and if effects persist after cessation of supplementation. We searched the Cochrane Central Register of Controlled Trials (CENTRAL Issue 3, 2009), MEDLINE (1966 to present), EMBASE (1980 to present), CINAHL (1982 to present), AMED (1985 to present) and ISI Web of Science (1945 to present) on 9 August 2009, and we handsearched key journal conference abstracts. Placebo-controlled RCTs of vitamin D supplementation for at least three months in healthy children and adolescents (aged from one month to < 20 years) with bone density outcomes. Two authors screened references for inclusion, assessed risk of bias, and extracted data. We conducted meta-analyses and calculated standardised mean differences (SMD) of the percent change from baseline in outcomes in treatment and control groups. We performed subgroup analyses by sex, pubertal stage, dose of vitamin D and baseline serum vitamin D and considered these as well as compliance and allocation concealment as possible sources of heterogeneity. We included six RCTs (343 participants receiving placebo and 541 receiving vitamin D) for meta-analyses. Vitamin D supplementation had no statistically significant effects on total body bone mineral content (BMC), hip bone mineral density (BMD) or forearm BMD. There was a trend to a small effect on lumbar spine BMD (SMD 0.15, 95% CI -0.01 to 0.31, P = 0.07). There were no differences in effects between high and low serum vitamin D studies at any site though there was a trend towards a larger effect with low vitamin D for total body BMC (P = 0.09 for difference). In low serum vitamin D studies, significant effects on total body BMC and lumbar spine BMD were approximately equivalent to a 2.6% and 1.7 % percentage point greater change from baseline in the supplemented group. These results do not support vitamin D supplementation to improve bone density in healthy children with normal vitamin D levels, but suggest that supplementation of deficient children may be clinically useful. Further RCTs in deficient children are needed to confirm this.