Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly

Associations between serum calcium, 25(OH)D level and bone mineral density in adolescents

BACKGROUNDS

It is important to improve our understanding of the roles of calcium and vitamin D in bone health for preventing osteoporosis. We aimed at exploring the associations between serum calcium, vitamin D level, and bone mineral density (BMD) in adolescents included in the National Health and Nutrition Examination Survey (NHANES) 2001-2006.

METHODS

Weighted multivariate linear regression models were used to estimate the associations of serum calcium, 25(OH)D level with total BMD. Smooth curve fitting was used to explore the potential non-linear relationship.

RESULTS

A total of 5990 individuals aged between 12 and 19 years were included in this study. The fully-adjusted model showed serum calcium positively correlated with total BMD. However, an inverted U-shaped relationship was found when we performed the smooth curve fitting method, and the inflection point was calculated at 9.6 mg/dL using the two-piecewise linear regression model. In contrast, there was a positive correlation between serum 25(OH)D and total BMD after adjusting for potential confounders.

CONCLUSIONS

The present study revealed a positive correlation between serum 25(OH)D level and total BMD, and an inverted U-shaped relationship between serum calcium and total BMD.

Low Energy Availability with and without a High-Protein Diet Suppresses Bone Formation and Increases Bone Resorption in Men: A Randomized Controlled Pilot Study

Suppression of insulin-like growth factor 1 (IGF-1) and leptin secondary to low energy availability (LEA) may contribute to adverse effects on bone health. Whether a high-protein diet attenuates these effects has not been tested. Seven men completed three five-day conditions operationally defined as LEA (15 kcal kg fat-free mass (FFM)⁻¹·day⁻¹) with low protein (LEA-LP; 0.8 g protein·kg body weight (BW)⁻¹), LEA with high protein (LEA-HP; 1.7 g protein·kg BW⁻¹) and control (CON; 40 kcal·kg FFM⁻¹·day⁻¹, 1.7 g protein·kg BW⁻¹). In all conditions, participants expended 15 kcal·kg FFM⁻¹·day⁻¹ during supervised cycling sessions. Serum samples were analyzed for markers of bone turnover, IGF-1 and leptin. The decrease in leptin during LEA-LP (−65.6 ± 4.3%) and LEA-HP (−54.3 ± 16.7%) was greater than during CON (−25.4 ± 11.4%; p = 0.02). Decreases in P1NP (p = 0.04) and increases in CTX-I (p = 0.04) were greater in LEA than in CON, suggesting that LEA shifted bone turnover in favour of bone resorption. No differences were found between LEA-LP and LEA-HP. Thus, five days of LEA disrupted bone turnover, but these changes were not attenuated by a high-protein diet.

Milk proteins and their derived peptides on bone health: Biological functions, mechanisms, and prospects

Bone is a dynamic organ under constant metabolism (or remodeling), where a delicate balance between bone resorption and bone formation is maintained. Disruption of this coordinated bone remodeling results in bone diseases, such as osteoporosis, the most common bone disorder characterized by decreased bone mineral density and microarchitectural deterioration. Epidemiological and clinical evidence support that consumption of dairy products is beneficial for bone health; this benefit is often attributed to the presence of calcium, the physiological contributions of milk proteins on bone metabolism, however, are underestimated. Emerging evidence highlighted that not only milk proteins (including individual milk proteins) but also their derived peptides positively regulate bone remodeling and attenuate bone loss, via the regulation of cellular markers and signaling of osteoblasts and osteoclasts. This article aims to review current knowledge about the roles of milk proteins, with an emphasis on individual milk proteins, bioactive peptides derived from milk proteins, and effect of milk processing in particular fermentation, on bone metabolism, to highlight the potential uses of milk proteins in the prevention and treatment of osteoporosis, and, to discuss the knowledge gap and to recommend future research directions.

Factors influencing peak bone mass gain

Bone mass is a key determinant of osteoporosis and fragility fractures. Epidemiologic studies have shown that a 10% increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50%. Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood. Race, gender, and family history (genetics) are responsible for the majority of PBM, but other factors, such as physical activity, calcium and vitamin D intake, weight, smoking and alcohol consumption, socioeconomic status, age at menarche, and other secondary causes (diseases and medications), play important roles in PBM gain during childhood and adolescence. Hence, the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people, and thus to reduce the low bone mass or osteoporosis risk in later life. This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

Lifestyle and Environmental Factors Affecting Bone Mass in Japanese Female Adolescents

PURPOSE

A higher peak bone mass (PBM) in adolescence lowers the risk of osteoporosis later in life. This study examined the factors affecting bone mass in female adolescents in relation to lifestyle and environmental factors to promote bone mass development before reaching PBM.

DESIGN AND METHODS

The subjects were female students aged 15-16 years and their mothers at a public high school in Osaka, Japan. Bone mass was measured using quantitative ultrasound parameters. The body composition was measured using a multi-frequency segmental body composition analyzer. Nutrient intake, exercise habits, and maternal factors as environmental factors were examined using a questionnaire.

RESULTS

Logistic regression analyses revealed that the adolescents' lean mass was significantly related to the BUA (p < .05). The adjusted odds ratio was 1.29 (95% confidence interval [CI]: 1.07-1.54). In contrast, the adolescents' exercise habit was significantly related to the SOS (p < .05). The SOS was significantly higher in the adolescents who exercised >4 times a week than in those who exercised <2-3 times a week. The adjusted odds ratio was 2.83 (95% CI: 1.06-7.56). The adolescents' nutrient intake and maternal factors were not significant factors affecting the adolescents' bone mass.

CONCLUSIONS

The present study suggests that increasing lean mass and exercising more than four times a week were important for increasing bone mass in female adolescents.

PRACTICE IMPLICATIONS

Nurses should intervene to help female adolescents acquire healthy lifestyle skills and maintain proper body composition and exercise habits to promote bone mass development before reaching PBM.

Associations between cola consumption and bone mineral density in Korean adolescents and young adults: a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey, 2008-2011

The present study aimed to elucidate the relationship between cola consumption and bone mineral density (BMD) in Korean adolescents and young adults. We used data from the Korea National Health and Nutrition Examination Survey 2008–2011. A total of 2499 adolescents and young adults aged 12–25 years were included. The study participants were classified as cola drinkers and non-cola drinkers according to 24-h dietary recall data. BMD was measured using dual X-ray absorptiometry. In the male population, whole body, whole femur and femoral neck BMD in cola drinkers were lower than that of non-cola drinkers by 4% (95% CI −0⋅071, −0⋅007), 5% (−0⋅092, −0⋅012) and 5% (−0⋅090, −0⋅001), respectively. In both sex groups, cola drinkers had less frequent milk consumption than non-cola drinkers. However, there were no significant differences in cola consumption according to calcium intake in both sexes. In conclusion, cola intake and BMD were inversely associated with Korean male adolescents and young adults. Considering the importance of peak bone mass attainment at adolescents and the increasing trend in carbonated beverage consumption in South Korea, further studies are needed to elucidate the causality between cola intake and lower BMD.

Impact of Type 1 Diabetes Mellitus on Skeletal Integrity and Strength in Adolescents as Assessed by HRpQCT

Adults with type 1 diabetes mellitus (T1DM) are at risk of premature osteoporosis and fractures. The onset of T1DM typically starts during childhood and adolescence. Thus, the effects of DM on the skeleton may be established during this period. Studies in children with T1DM primarily use DXA with conflicting results. We present the first study in adolescents assessing the impact of T1DM on skeletal microstructure and strength using HRpQCT. We recruited 22 patients aged 12 to 16 years with T1DM who were matched by age, gender, and pubertal stage with healthy controls. Paired t tests were applied to assess differences in cortical and trabecular microarchitecture measurements from HRpQCT, and skeletal strength from HRpQCT-derived microfinite element analysis. Subtotal body, lumbar, and pelvic parameters were assessed using DXA. There was no significant difference in subtotal body, lumbar spine, and pelvic BMD between T1DM and control pairs. However, tibial trabecular thickness was lower (-0.005 mm; 95% CI, -0.01 to -0.001; p = 0.029) and trabecular loading was lower at the distal radius (ratio of the load taken by the trabecular bone in relation to the total load at the distal end (Tb.F/TF) distal: -6.2; 95% CI, -12.4 to -0.03; p = 0.049), and distal and proximal tibia (Tb.F/TF distal: -5.2, 95% CI, -9.2 to -1.2; p = 0.013; and Tb.F/TF proximal: -5.0, 95% CI, -9.8 to -0.1; p = 0.047) in T1DM patients. A subanalysis of radial data of participants with duration of T1DM of at least 2 years and their matched controls demonstrated a reduced trabecular bone number (-0.15, 95% CI, -0.26 to -0.04; p = 0.012), increased trabecular separation (0.041 mm, 95% CI, 0.009-0.072; p = 0.015), an increased trabecular inhomogeneity (0.018, 95% CI, 0.003-0.034; p = 0.021). Regression models demonstrated a reduction in tibial stiffness (-0.877 kN/mm; p = 0.03) and tibial failure load (-0.044 kN; p = 0.03) with higher HbA1C. Thus, in adolescents with T1DM, detrimental changes are seen in tibial and radial microarchitecture and tibial and radial strength before changes in DXA occur and may result from poor diabetic control. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

The effect of an online exercise programme on bone health in paediatric cancer survivors (iBoneFIT): study protocol of a multi-centre randomized controlled trial

BACKGROUND

New approaches on paediatric cancer treatment aim to maintain long-term health. As a result of radiotherapy, chemotherapy or surgery, paediatric cancer survivors tend to suffer from any chronic health condition. Endocrine dysfunction represents one of the most common issues and affects bone health. Exercise is key for bone mass accrual during growth, specifically plyometric jump training. The iBoneFIT study will investigate the effect of a 9-month online exercise programme on bone health in paediatric cancer survivors. This study will also examine the effect of the intervention on body composition, physical fitness, physical activity, calcium intake, vitamin D, blood samples quality of life and mental health.

METHODS

A minimum of 116 participants aged 6 to 18 years will be randomized into an intervention (n = 58) or control group (n = 58). The intervention group will receive an online exercise programme and diet counselling on calcium and vitamin D. In addition, five behaviour change techniques and a gamification design will be implemented in order to increase the interest of this non-game programme. The control group will only receive diet counselling. Participants will be assessed on 3 occasions: 1) at baseline; 2) after the 9 months of the intervention; 3) 4 months following the intervention. The primary outcome will be determined by dual energy X-ray absorptiometry (DXA) and the hip structural analysis, trabecular bone score and 3D-DXA softwares. Secondary outcomes will include anthropometry, body composition, physical fitness, physical activity, calcium and vitamin D intake, blood samples, quality of life and mental health.

DISCUSSION

Whether a simple, feasible and short in duration exercise programme can improve bone health has not been examined in paediatric cancer survivors. This article describes the design, rationale and methods of a study intended to test the effect of a rigorous online exercise programme on bone health in paediatric cancer survivors. If successful, the iBoneFIT study will contribute to decrease chronic health conditions in this population and will have a positive impact in the society.

TRIAL REGISTRATION

Prospectively registered in isrctn.com: isrctn61195625 . Registered 2 April 2020.

Associations of Sex Steroids With Changes in Calcaneal Quantitative Ultrasound Measurements: A Longitudinal Study in Chinese Male Adolescents

This 2-year longitudinal study aimed to detect the associations of sex steroids, sex hormone-binding globulin with bone parameters and the changes thereof in Chinese male adolescents. A total of 642 male students aged 12-16 years from a secondary school in Jiangmen, China, were included. Total testosterone (T), total oestradiol (E2), and sex hormone-binding globulin were measured by chemiluminescence immunoassay. The bioavailable T (BioT) and E2 (BioE2) were calculated. The speed of sound, broadband ultrasound attenuation, and stiffness index of the right heel were measured by Sahara Clinical Bone Sonometer at both baseline and 2-year follow-up. The confounding effects of age, height, weight, pubertal stage, physical activity, energy-adjusted dietary calcium intake, and dietary vitamin D intake were adjusted. The baseline value of each bone parameter was also adjusted in the longitudinal analysis. Results showed that total T and BioT were positively associated with bone parameters and changes in them (β = 0.076-0.115, p < 0.05). A threshold effect of BioT on broadband ultrasound attenuation, stiffness index and their changes were also observed. Positive associations between BioT and bone mass gain were observed only in individuals with BioT levels <240.0 ng/dl (β = 0.088-0.131, p < 0.05). Moreover, total E2 or BioE2 were found to be inversely associated with speed of sound and its change (β = -0.109 to -0.077, p < 0.05). This study supported that in Chinese male adolescents, serum T was a positive predictor for bone formation with a threshold effect, and E2 could have influence on the changes in bone architecture during puberty. These findings may improve the understanding of the effects of sex steroids on the acceleration of bone formation in male adolescents and provide useful information for the prediction model establishment of peak bone mass.

Determinants of bone health in adults Polish women: The influence of physical activity, nutrition, sun exposure and biological factors

Purpose

The aim of this study was to assess the determinants of bone health in the group of women over 40 years old. Lifestyle factors such as past and present physical activity, past and present sun exposure, current dietary intake of calcium and vitamin D, nutritional status as measured by BMI, family history of osteoporosis and current hormonal status were analysed.

Methods

The study involved 500 women over 40 years old. All examined women was the same ethnicity- European origin. Methods used: densitometry method (DXA), bioelectrical impedance analysis, International Physical Activity Questionnaire, nutrition questionnaire, past and present sun exposure questionnaire. Past and present physical activity, past and present sun exposure and sufficient level of calcium in the diet proved to be the most important factors determining mineralization of bone tissue of women. In order to indicate an independent association of the correct bone tissue mineralization with individual factors, multivariate analysis was used—logistic regression.

Results

The norm BMD in the distal part of the forearm was strongly influenced: recommended dietary calcium intake (OR = 5.95; p = 0.003), moderately (OR = 1.88; p = 0.053) and high (OR = 14.0; p<0.001) past physical activity, sufficient (OR = 4.97; p<0.001) and high (OR = 18.9; p = 0.004) level of present physical activity, sufficient past (OR = 5.15; p<0.001) and sufficient present sun exposure (OR = 10.0; p<0.001).

The chance for the BMD prox norm was also increased several times: high past physical activity (OR = 68.4; p<0.0001) and sufficient past sun exposure (OR = 10.6; p<0.001), moderate past activity (OR = 4.20; p<0.001), sufficient (OR = 6.13; p<0.001) and high (OR = 10.0; p<0.001) present physical activity, sufficient present sun exposure (OR = 9.09; p<0.0001), recommended intake of calcium (OR = 9.57; p<0.001) and vitamin D (OR = 2.68; p = 0.052). Whereas e significantly lower likelihood for the BMD prox norm was found in women with the oldest hormonal status (postmenopausal period) (OR = 0.18; p<0.001), with osteoporosis in the family (OR = 0.37; p<0.001) and living in an agglomeration (OR = 0.68; p = 0.03).

Conclusion

Interventions to increase physical activity, especially outdoors, may help reduce risk of osteoporosis, fractures and subsequent healthcare costs.

Bone density, microarchitecture and strength estimates in white versus African American youth with obesity

BACKGROUND

African Americans (AA) have more favorable bone density and microarchitecture compared to Whites (W), which may explain their observed lower fracture rates. Obesity has deleterious effects on bone microarchitecture and strength estimates and is associated with an increase in fracture risk. Adolescence and young adulthood are periods of active bone accrual and also periods characterized by an increasing prevalence of obesity. The effect of obesity on the relationship between race and bone parameters remains unclear, particularly in youth.

OBJECTIVE

To assess differences in BMD, bone microarchitecture and strength estimates in AA and W adolescents and young adults with moderate to severe obesity. We hypothesized that racial differences in bone endpoints in lean youth would also be noted in youth with moderate to severe obesity.

METHODS

We evaluated 24 AA and 48 W adolescent and young adults with a mean age of 18.2 ± 2.4 years and a median body mass index (BMI) of 44.8 (40.5-49.4) kg/m2 who underwent dual energy X-ray absorptiometry (DXA), high resolution peripheral quantitative computed tomography (HRpQCT), extended cortical analysis (ECA) and micro-finite element analysis (FEA) to obtain measures of volumetric bone mineral density (vBMD), bone geometry, microarchitecture, and strength estimates at the distal radius and tibia.

RESULTS

We found no differences between AA and W for total fat and lean mass, and areal BMD Z-scores (p > 0.05 for all). At the distal radius, no significant differences were detected in vBMD, bone geometry or microarchitecture (p > 0.05 for all); however, stiffness and failure load were higher in the AA group (p = 0.031 and 0.047 respectively). At the distal tibia, cortical vBMD was higher in AA vs. W (p = 0.012), while trabecular number was higher and trabecular separation lower in W vs. AA (p ≤ 0.028). Stiffness and failure load trended higher in AA vs. W (p = 0.052 and p = 0.048, respectively). Groups did not differ for any other bone parameter (p > 0.05).

CONCLUSION

Racial differences in bone endpoints appear to be less marked in those with moderate to severe obesity, suggesting that effects of obesity may blunt the effect of race on bone endpoints.

Hydrolyzed Rice Protein-Based Formulas, a Vegetal Alternative in Cow's Milk Allergy

Formulas adapted to infant feeding, although most of the time made from cow's milk proteins, can be made from hydrolyzed rice protein but they must be classified as "formulas for specific medical needs", according to European regulations. The nutritional quality of rice proteins is thus suitable to be used in infant formulas giving that it is supplemented by certain amino acids which can be lacking. Besides, hydrolysis is required to facilitate their water solubility and digestibility. Owing to a low allergenicity of rice and to the absence of the cross-allergy between milk proteins and rice proteins, these formulas are adapted to the diet of children with cow's milk protein allergy (CMPA), which explains their growing use in some countries. However, CMPA, an expanding disorder, has consequences for growth, bone mineralization, and often has an association with allergy to other foods, including cow's milk extensive hydrolysate, so that a surveillance of the adaption of hydrolyzed rice protein formulas (HRPF) to CMPA, the absence of unexpected side effects, and the appropriate response to its various health hazards seems mandatory. This paper analyses the health problem deriving from CMPA, the industrial development of hydrolyzed rice protein formulas, and the limited number of clinical studies, which confirms, at the moment, a good allergic tolerance and safety. The goal is to better advise heath care professionals on their use of HRPFs during CMPA.

Bone health in childhood cancer: review of the literature and recommendations for the management of bone health in childhood cancer survivors

In the past decades, new cancer treatment approaches for children and adolescents have led to a decrease in recurrence rates and an increase in long-term survival. Recent studies have focused on the evaluation of the late effects on bone of pediatric cancer-related treatments, such as chemotherapy, radiation and surgery. Treatment of childhood cancer can impair the attainment of peak bone mass, predisposing to premature onset of low bone mineral density, or causing other bone side-effects, such as bone quality impairment or avascular necrosis of bone. Lower bone mineral density and microarchitectural deterioration can persist during adulthood, thereby increasing fracture risk. Overall, long-term follow-up of childhood cancer survivors is essential to define specific groups at higher risk of long-term bone complications, identify unrecognized long-term adverse effects, and improve patient care. Children and adolescents with a cancer history should be carefully monitored, and patients should be informed of possible late complications of their previous medical treatment. The International Osteoporosis Foundation convened a working group to review the bone complications of pediatric cancer survivors, outlining recommendations for the management of bone health, in order to prevent and treat these complications.

Effect of soluble corn fiber supplementation for 1 year on bone metabolism in children, the MetA-bone trial: Rationale and design

Calcium intake is critical for adequate bone mineralization in adolescence, but it is usually inadequate in US adolescents. A strategy to maximize bone mineralization is to increase calcium absorption, which could be achieved by soluble corn fiber (SCF). There are no studies determining the long-term effects of SCF on bone mass in children.

OBJECTIVES

To determine the effect of one-year SCF supplementation compared to placebo on bone mass and bone biomarkers in children with low habitual calcium intake. We hypothesize that SCF supplementation will result in a higher bone mineral content and higher levels of bone formation and lower bone resorption biomarkers.

METHODS

240 healthy children (10-13 years), with usual low calcium intake, will be randomized to four experimental groups for 1 year: (1) SCF (12 g/d); (2) SCF (12 g/d) + 600 mg/d of calcium; (3) Placebo (maltodextrin); and (4) Placebo +600 mg/d of calcium. The supplements have been pre-mixed with a flavored powder beverage and participants will only need to dilute it in water and drink this twice per day. Bone will be measured using dual energy x-ray absorptiometry (DXA) at baseline, 6 and 12 months. Serum bone biomarkers will be measured at baseline and at 12 months.

CONCLUSIONS

If supplementing diets with SCF lead to higher bone mass during adolescence, this could help achieve the genetic potential for PBM and to start adult life with stronger bones. If successful, SCF can be incorporated into diets for promoting bone health in adolescents.

Physical Fitness and Bone Health in Young Athletes and Nonathletes

BACKGROUND

Physical activity (PA) and physical fitness (PF) are crucial for bone health. However, children participating in competitive sports with high PA are at a greater risk of fracture from trauma or overuse. Given the importance of bone development during adolescence, associations between commonly used physical fitness tests with distal third radius (R-SoS) and midshaft tibia (T-SoS) speed of sound by quantitative ultrasound were assessed in adolescent athletes and nonathletes.

HYPOTHESIS

The relationship between physical fitness tests and R-SoS and T-SoS will differ depending on sex and athletic status.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Physical fitness of 285 boys (156 athletes) and 311 girls (74 athletes) aged 10 to 18 years was assessed through strength, speed, agility, and cardiorespiratory tests. Linear regression was used to assess the associations of physical fitness tests with R-SoS and T-SoS.

RESULTS

For boys, favorable associations were observed between physical fitness tests with R-SoS in athletes and T-SoS in both athletes and nonathletes (P < 0.05). For nonathlete girls, favorable associations were found for handgrip (R-SoS and T-SoS, both P < 0.05), whereas the progressive aerobic cardiovascular endurance run, vertical jump, speed at 20 m and 40 m were only favorably associated with T-SoS. For athlete girls, the association between handgrip (P = 0.03), vertical jump, and 4 × 10 m shuttle run (P < 0.05) with T-SoS was significantly related to a bone outcome.

CONCLUSION

The handgrip test and vertical jump were associated with T-SoS in boys and girls independent of sport status. These results suggest that physical fitness is associated with bone health in adolescents, particularly boys, and that the relationship between physical fitness and bone may differ depending on sex and athletic status.

CLINICAL RELEVANCE

Physical fitness tests are simple, easy-to-use tools for monitoring bone health and should be used by sport and health professsionals to promote healthy sport participation and prevent bone injuries.

Usual Dietary Intake, Nutritional Adequacy and Food Sources of Calcium, Phosphorus, Magnesium and Vitamin D of Spanish Children Aged One to <10 Years. Findings from the EsNuPI Study

Bone problems in the population begin to be establish in childhood. The present study aims to assess the usual calcium, phosphorus, magnesium, and vitamin D intakes, along with the food sources of these nutrients, in Spanish children participating in the EsNuPI (Estudio Nutricional en Población Infantil Española) study. Two 24 h dietary recalls were applied to 1448 children (1 to <10 years) divided into two sub-samples: one reference sample (RS) of the general population [n = 707] and another sample which exclusively included children consuming enriched or fortified milks, here called "adapted milks" (AMS) [n = 741]. Estimation of the usual intake shows that nutrient intake increased with age for all nutrients except vitamin D. Using as reference the Dietary Reference Values from the European Food Safety Authority (EFSA), calcium and magnesium intakes were found to be below the average requirement (AR) and adequate intake (AI), respectively, in a considerable percentage of children. Furthermore, phosphorus exceeded the AI in 100% of individuals and vitamin D was lower than the AI in almost all children studied. The results were very similar when considering only plausible reporters. When analyzing the food sources of the nutrients studied, milk and dairy products contributed the most to calcium, phosphorus, magnesium, and vitamin D. Other sources of calcium were cereals and vegetables; for phosphorus: meat, meat products, and cereals; for magnesium: cereals and fruits; and, for vitamin D: fish and eggs. These results highlight the desirability of improving the intake concerning these nutrients, which are involved in bone and metabolic health in children. The AMS group appeared to contribute better to the adequacy of those nutrients than the RS group, but both still need further improvement. Of special interest are the results of vitamin D intakes, which were significantly higher in the AMS group (although still below the AI), independent of age.

Prevalence of osteoporosis among North Korean women refugees living in South Korea: a comparative cross-sectional study

OBJECTIVE

To investigate the prevalence of osteoporosis among North Korean women refugees when compared with South Korean women, who have identical genetic backgrounds but experience different environments.

DESIGN

Comparative cross-sectional study.

SETTING

North Korean Refugee Health in South Korea (NORNS) study in South Korea.

PARTICIPANTS

We evaluated 122 North Korean women who participated in NORNS study and 366 age-matched/menopausal status-matched South Korean women from the Korea University Medical Center (KUMC) health examination cohort. The median age of the NORNS participants was 46 years (IQR, 40-60 years) with 52 women (42.6%) being postmenopausal.

RESULTS

Among the postmenopausal women, NORNS participants had a higher body mass index and number of pregnancies and lower physical activity than the KUMC participants. The overall prevalence of osteoporosis was 48% (25/52) and 17% (27/156) in NORNS and KUMC participants, respectively. The bone mineral density (BMD) values at the lumbar spine, femur neck and total hip were significantly lower in postmenopausal NORNS women than in the postmenopausal KUMC women. Old age, low body weight and late age of menarche were associated with low BMD among the postmenopausal North Korean refugees. In premenopausal participants, the NORNS women had lower body weight and physical activity than the KUMC women at baseline. All the NORNS women had normal Z-scores, although the BMD at the lumbar spine was significantly lower in NORNS women than in the KUMC women (0.952 vs 1.002 g/cm2, p<0.001).

CONCLUSIONS

Osteoporosis is a prevalent health problem in postmenopausal North Korean women refugees living in South Korea. It is conceivable to prepare vigilant countermeasures for bone health deterioration in this growing population, especially for postmenopausal women. Further research is warranted to determine the cause of the differences between participants of the same ethnic group.

Association Between Physical Fitness and Bone Strength and Structure in 3- to 5-Year-Old Children

BACKGROUND

The positive association between physical fitness and bone structure has been widely investigated in children and adolescents, yet no studies have evaluated this influence in young children (ie, preschoolers).

HYPOTHESIS

Fit children will present improved bone variables when compared with unfit children, and no sex-based differences will emerge in the sample.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Handgrip strength, standing long jump (SLJ), speed/agility, balance, and cardiorespiratory fitness (CRF) were assessed using the Assessing FITness levels in PREschoolers (PREFIT) test battery in 92 children (50 boys; age range, 3-5 years). A peripheral quantitative computed tomography scan was performed at 38% of the length of the nondominant tibia. Cluster analysis from handgrip strength, SLJ, speed/agility, and CRF was developed to identify fitness groups. Bone variables were compared between sexes and between cluster groups. The association between individual physical fitness components and different bone variables was also tested.

RESULTS

Three cluster groups emerged: fit (high values on all included physical fitness variables), strong (high strength values and low speed/agility and CRF), and unfit (low strength, speed/agility, and CRF). The fit group presented higher values than the strong and unfit groups for total and cortical bone mineral content, cortical area, and polar strength strain index (all P < 0.05). The fit group also presented a higher cortical thickness when compared with the unfit group (P < 0.05). Handgrip, SLJ, and speed/agility predicted all bone variables except for total and cortical volumetric bone mineral density. No differences were found for bone variables between sexes.

CONCLUSION

The results suggest that global fitness in preschoolers is a key determinant for bone structure and strength but not volumetric bone mineral density.

CLINICAL RELEVANCE

Physical fitness is a determinant for tibial bone mineral content, structure, and strength in very young children. Performing physical fitness tests could provide useful information related to bone health in preschoolers.

Effect of pre-treatment of strength training and raloxifene in periestropause on bone healing

BACKGROUND

There is evidence that strength training (ST) and raloxifene (Ral) treatment during periestropause promotes better bone quality. We wanted to determine whether the skeletal benefits of ST or Ral treatment, performed during periestropause, would persist after fracture. Therefore, the present study aimed to analyze the influence of pre-treatment with ST and administration of Ral during periestropause on bone healing after total unilateral osteotomy.

METHODS

Senescent female Wistar rats between 18 and 21 months of age, performed ST on a ladder three times per week, were administered Ral by gavage (2.3 mg/kg/day), or an association of both. After 120 days, the treatments were interrupted, and a total osteotomy was performed on the left tibia in all animals. They were euthanized 1 and 8 weeks post-osteotomy.

RESULTS

The administration of Ral during periestropause worsened the biochemical and oxidative profile, decreased gene expression of markers related to bone resorption and remodeling, which negatively affected the physicochemical properties; this lead to changes in the bone callus microarchitecture and mass, as well as a decrease in callus resistance to torsional deformation, resulting in lower tissue quality during bone healing. In contrast, ST performed prior to the osteotomy resulted in better bone healing, improvement of the biochemical and oxidative profile, alteration of the genetic profile in favor of bone formation and resorption, as well as the physic-ochemical properties of the callus. These changes led to better microarchitecture and bone mass and increased callus resistance to torsional deformation, confirming its beneficial effect on the quality of bone tissue, providing acceleration of bone consolidation. The combination of therapies at this exercise intensity and drug dosage showed a negative interaction, where the negative effect of Ral overcame the positive effect of ST, leading to decreased tissue quality in the bone healing process.

CONCLUSIONS

This study indicates that in addition to excellent non-pharmacological therapy and action in the prevention of osteoporosis, ST performed during the aging period may increase bone quality at the onset of healing and provide improved bone consolidation. Furthermore, the anti-osteoclastogenic effect of Ral shown in this model delayed the bone repair process, resulting in considerable clinical concern.

Bone accrual over 18 months of participation in different loading sports during adolescence

This study investigated the impact and non-impact sports on bone mineral density accrual in adolescents over 18 months. The impact sports were beneficial for bone health (accrual of bone density). In contrast, swimmers had similar or lower bone mineral density compared with the control group depending on the skeletal site.

PURPOSE

To investigate the impact and non-impact sports on bone mineral density (BMD) accrual in adolescents over a period of 18 months METHODS: The sample was composed of 71 adolescents, avarage age of 12.7 (± 1.7) years old at baseline. Bone outcomes were compared according to the loading of the sports practiced (impact sports, n = 33 [basketball, karate, and judo], non-impact sport, n = 18 [swimming], and control group, n = 20). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) and bone mineral apparent density (BMAD) estimated through equation. The results were compared between the groups using analysis of variance and analysis of covariance.

RESULTS

Adjusted aBMD at lower limbs, whole body less head (WBLH), and adjusted WBLH BMAD were significantly greater in the impact sport group than the non-impact sport group at all time points. Adjusted upper limbs aBMD was significantly higher at the impact sports group compared to the non-impact sport group at 9 months and 18 months, besides compared to the control group at baseline and 18 months. Non-impact sport group presented a significant lower adjusted aBMD compared with control group at lower limbs and WBLH at 9 months, and at 9 months and 18 months in WBLH BMAD. There was a significant interaction (time × sport group) at upper limbs (p = 0.042) and WBLH aBMD (p = 0.006), and WBLH BMAD (p < 0.001).

CONCLUSION

Impact sports were more beneficial on accumulating aBMD and BMAD over a period of 18 months, while non-impact group (swimmers) had similar and lower aBMD and BMAD compared with the control group.

The Important Role of Adiponectin and Orexin-A, Two Key Proteins Improving Healthy Status: Focus on Physical Activity

Exercise represents the most important integrative therapy in metabolic, immunologic and chronic diseases; it represents a valid strategy in the non-pharmacological intervention of lifestyle linked diseases. A large body of evidence indicates physical exercise as an effective measure against chronic non-communicable diseases. The worldwide general evidence for health benefits are both for all ages and skill levels. In a dysregulated lifestyle such as in the obesity, there is an imbalance in the production of different cytokines. In particular, we focused on Adiponectin, an adipokine producted by adipose tissue, and on Orexin-A, a neuropeptide synthesized in the lateral hypothalamus. The production of both Adiponectin and Orexin-A increases following regular and structured physical activity and both these hormones have similar actions. Indeed, they improve energy and glucose metabolism, and also modulate energy expenditure and thermogenesis. In addition, a relevant biological role of Adiponectin and Orexin A has been recently highlighted in the immune system, where they function as immune-suppressor factors. The strong connection between these two cytokines and healthy status is mediated by physical activity and candidates these hormones as potential biomarkers of the beneficial effects induced by physical activity. For these reasons, this review aims to underly the interconnections among Adiponectin, Orexin-A, physical activity and healthy status. Furthermore, it is analyzed the involvement of Adiponectin and Orexin-A in physical activity as physiological factors improving healthy status through physical exercise.

Isolated Cyclic Loading During Adolescence Improves Tibial Bone Microstructure and Strength at Adulthood

Bone is a unique living tissue, which responds to the mechanical stimuli regularly imposed on it. Adolescence facilitates a favorable condition for the skeleton that enables the exercise to positively influence bone architecture and overall strength. However, it is still dubious for how long the skeletal benefits gained in adolescence is preserved at adulthood. The current study aims to use a rat model to investigate the effects of in vivo low- (LI), medium- (MI), and high- (HI) intensity cyclic loadings applied during puberty on longitudinal bone development, morphometry, and biomechanics during adolescence as well as at adulthood. Forty-two young (4-week-old) male rats were randomized into control, sham, LI, MI, and HI groups. After a 5 day/week for 8 weeks cyclic loading regime applied on the right tibia, loaded rats underwent a subsequent 41-week, normal cage activity period. Right tibias were removed at 52 weeks of age, and a comprehensive assessment was performed using μCT, mechanical testing, and finite element analysis. HI and MI groups exhibited reduced body weight and food intake at the end of the loading period compared with shams, but these effects disappeared afterward. HI cyclic loading increased BMD, bone volume fraction, trabecular thickness, trabecular number, and decreased trabecular spacing after loading. All loading-induced benefits, except BMD, persisted until the end of the normal cage activity period. Moreover, HI loading induced enhanced bone area, periosteal perimeter, and moment of inertia, which remained up to the 52nd week. After the normal cage activity at adulthood, the HI group showed increased ultimate force and stress, stiffness, postyield displacement and energy, and toughness compared with the sham group. Overall, our findings suggest that even though both trabecular and cortical bone drifted through age-related changes during aging, HI cyclic loading performed during adolescence can render lifelong benefits in bone microstructure and biomechanics. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

High impact physical activity and bone health of lower extremities in childhood cancer survivors: A cross-sectional study of SURfit

Childhood cancer survivors (CCS) are at risk of reduced bone health and premature osteoporosis. As physical activity with high impact loading (IL-PA) is known to promote bone health, we compared bone densitometry and microstructure between groups of CCS who performed different amounts of physical activities in their daily life. We used baseline data of a single-center PA trial including 161 CCS from the Swiss Childhood Cancer Registry, aged <16 at diagnosis, ≥16 at study and ≥5 years since diagnosis. Lower body bone health was assessed with peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA). Daily IL-PA (duration in activities >2 g acceleration and numbers of vertical impacts/hr >2 g) was captured using hip-worn accelerometers (1-3 weeks). For both IL-PA approaches, we formed low, middle and high activity groups based on tertiles. Bone health of the high and middle active groups was compared to the low active group. 63% of CCS had indication of at least one bone mineral density z-score ≤ -1 measured by pQCT or DXA. The high IL-PA group performing 2.8 min/day or 19.1 impact peaks/hr > 2 g (median) showed about 3-13% better microstructural and densitometric bone health as compared to the low IL-PA group with 0.38 min/day or 0.85 peaks/hr > 2 g. Just a few minutes and repetitions of high IL-PA as easily modifiable lifestyle factor may be sufficient to improve bone health in adult CCS. Future longitudinal research is needed to better understand pattern and dosage of minimal impact loading needed to strengthen bone in growing and adult CCS.

The long-term residual effects of low-magnitude mechanical stimulation therapy on skeletal health

Background

Low-magnitude mechanical stimulation (LMMS) may improve skeletal health. The objective of this research was to investigate the long-term residual effects of LMMS on bone health. 10-week old female mice were given LMMS for 8 weeks; SHAM did not receive LMMS. Some groups remained on study for an additional 8 or 16 weeks post treatment (N = 17).

Results

Epiphyseal trabecular mineralizing surface to bone surface ratio (MS/BS) and bone formation rate (BFR/BS) were significantly greater in the LMMS group compared to the SHAM group at 8 weeks by 92 and 128% respectively. Mineral apposition rate (MAR) was significantly greater in the LMMS group 16 weeks post treatment by 14%.

Metaphyseal trabecular bone mineral density (BMD) increased by 18%, bone volume tissue volume ratio (BV/TV) increased by 37%, and trabecular thickness (Tb.Th.) increased by 10% with LMMS at 8 weeks post treatment. Significant effects 16 weeks post treatment were maintained for BV/TV and Tb.Th. The middle-cortical region bone volume (BV) increased by 4% and cortical thickness increased by 3% with 8-week LMMS.

Conclusions

LMMS improves bone morphological parameters immediately after and in some cases long-term post LMMS. Results from this work will be helpful in developing treatment strategies to increase bone health in younger individuals.

Serum 25-hydroxyvitamin D concentrations in 16-year-old Icelandic adolescent and its association with bone mineral density

OBJECTIVE

The aim of the study was to assess the potential association between serum 25-hydroxyvitamin D (25(OH)D) and whole-body bone mineral density (BMD) among 16-year-old adolescents and to study the prevalence of 25(OH)D insufficiency, defined as concentration under 50 nmol/l.

DESIGN

A cross-sectional study.

SETTING

Reykjavik, Iceland, latitude 64°08'N. Measurements took place in the Icelandic Heart Association's research lab during April-June 2015.

PARTICIPANTS

In total, 411 students in Reykjavik, Iceland, were invited to participate, 315 accepted the invitation (76·6 %) and 289 had valid data (mainly Caucasian).

RESULTS

25(OH)D < 50 nmol/l was observed in 70 % of girls and 66·7 % of boys. 25(OH)D ≥ 50 nmol/l was significantly associated with higher whole-body BMD after adjusting for the influence of sex, height, fat mass and lean mass. A linear relationship between 25(OH)D and whole-body BMD was significant for 25(OH)D < 50 nmol/l (n 199, P < 0·05) but NS for 25(OH)D ≥ 50 nmol/l (n 86, P = 0·48).

CONCLUSIONS

Our results are in line with some but not all previous studies on the relationship between BMD and 25(OH)D in adolescents. The observed difference in BMD between those with above v. below a 25(OH)D concentration of 50 nmol/l was of about a fifth of one SD, which may have a clinical relevance as one SD decrease in volumetric BMD has been associated with a 89 % increase in 2 years risk of fracture. Icelandic adolescents should be encouraged to increase their vitamin D intake as it is possible that their current intake is insufficient to achieve optimal peak bone mass.

Association between dietary calcium intake and BMD in children and adolescents

Aim

Ensuring adequate calcium (Ca) intake during childhood and adolescence is critical to acquire good peak bone mass to prevent osteoporosis during older age. As one of the primary strategies to build and maintain healthy bones, we aimed to determine whether dietary Ca intake has an influence on bone mineral density (BMD) in children and adolescents.

Methods

We conducted a cross-sectional study composed of 10,092 individuals from the National Health and Nutrition Examination Survey (NHANES). Dietary Ca intake and total BMD were taken as independent and dependent variables, respectively. To evaluate the association between them, we conducted weighted multivariate linear regression models and smooth curve fittings.

Results

There was a significantly positive association between dietary Ca intake and total BMD. The strongest association was observed in 12-15 year old whites, 8-11 year old and 16-19 year old Mexican Americans, and 16-19 year old individuals from other race/ethnicity, in whom each quintile of Ca intake was increased. We also found that there were significant inflection points in females, blacks, and 12-15 year old adolescents group, which means that their total BMD would decrease when the dietary Ca intake was more than 2.6-2.8 g/d.

Conclusions

This cross-sectional study indicated that a considerable proportion of children and adolescents aged 8-19 years would attain greater total BMD if they increased their dietary Ca intake. However, higher dietary Ca intake (more than 2.6-2.8 g/d) is associated with lower total BMD in females, blacks, and 12-15 year old adolescents group.

Impact of changes in fat mass and lean soft tissue on bone mineral density accrual in adolescents engaged in different sports: ABCD Growth Study

Body composition can have a significant impact on bone mineral density (BMD) in pediatric patients and may cause bone disease. This study demonstrated that lean soft tissue (LST) seems to have a greater impact on BMD gain in the lower limbs of adolescents.

PURPOSE

To analyze the impact of changes in lean soft tissue (LST) and fat mass on areal bone mineral density (BMD) accrual in the lower limbs among adolescents engaged in sports with different weight-bearing levels.

METHODS

Longitudinal (12 months: measurements at two time points). Adolescents of both sexes (n = 191; 62 girls [32.5%] and 129 boys [67.5%]) were divided into three groups: control group (n = 65), swimming group (n = 25), and weight-bearing sports group (n = 100). Absolute changes in LST (kg) and fat mass (kg) were the independent variables, while BMD accrual (left and right legs) was the dependent variable. Linear regression was used to assess the relationship between dependent and independent variables in a multivariate model adjusted by sex, body weight, somatic maturation, serum osteocalcin, and baseline values of BMD of the lower limbs.

RESULTS

For the left leg, LST was positively related to areal BMD accrual in the control (β = 0.021 [95%CI: 0.001 to 0.042]) and weight-bearing sport groups (β = 0.051 [95%CI: 0.037 to 0.065]), but not among swimmers (β = 0.029 [95%CI: - 0.004 to 0.062]). For the right leg, LST was positively related to areal BMD accrual in the swimming group (β = 0.065 [95%CI: 0.031 to 0.100]) and weight-bearing sport groups (β = 0.048 [95%CI: 0.034 to 0.062]), but not in the control group (β = 0.014 [95%CI: - 0.002 to 0.030]). Fat mass was not significantly related to areal BMD in either leg.

CONCLUSIONS

Changes in LST were the most relevant determinant of BMD accrual in the lower limbs, mainly among adolescents engaged in sports.

Relationship between bone mineral content and bone turnover markers, sex hormones and calciotropic hormones in pre- and early pubertal children

We investigated associations between bone mineral content (BMC) and bone-related biomarkers (BM) in pre-and early pubertal children of both sexes. In this population, we found that bone turnover markers explain a small part of BMC variance.

INTRODUCTION

It is still debated whether BM including bone turnover markers (BTM), sex hormones and calciotropic (including cortisol) hormones provide information on BMC changes during growth.

METHODS

Three hundred fifty-seven girls and boys aged 6 to 13 years were included in this study. BM was measured at baseline and BMC twice at 9 months and 4 years using DXA. Relationship between BMs was assessed using principal component analysis (PCA). BM was tested in its ability to explain BMC variation by using structural equation modelling (SEM) on cross-sectional data. Longitudinal data were used to further assess the association between BM and BMC variables.

RESULTS

BMC and all BMs, except calciotropic hormones, increased with age. PCA in BM revealed a three-factor solution (BTM, sex hormones and calciotropic hormones). In the SEM, age accounted for 61% and BTM for 1.2% of variance in BMC (cross-sectional). Neither sex nor calciotropic hormones were BMC explanatory variables. In the longitudinal models (with single BM as explanatory variables), BMC, age and sex at baseline accounted for 79-81% and 70-75% in BMC variance at 9 months and 4 years later, respectively. P1NP was consistently associated with BMC.

CONCLUSION

BMC strongly tracks in pre- and early pubertal children. In this study, only a small part of BMC variance was explained by single BTM at the beginning of pubertal growth.

Body Composition as a Mediator between Cardiorespiratory Fitness and Bone Mass during Growth

INTRODUCTION AND PURPOSE

To examine the effect of cardiorespiratory fitness (CRF) and muscle power output (MPO) on bone mass of prepubertal and pubertal children using lean mass (LM) and percentage of fat mass (%FM) as mediator variables. The hypothesis was that both LM and %FM would be independent mediators of the relationships during the sexual maturation period.

METHODS

We analyzed 200 children (88 boys and 112 girls [11.5 ± 2.0 yr]). Body composition was analyzed by bone densitometry, and indirect calorimetry and cycle ergometer were used to calculate V˙O2peak (mL·kg·min) and MPO (W) during an incremental exercise test. Sample was divided by pubertal status.

RESULTS

In the prepubertal group, LM and %FM acted independently as mediators in the relationship between bone mass and CRF or MPO (22%-25% for LM and 37%-50% for %FM, respectively). In pubertal children, LM acted as mediator at 37%.

CONCLUSIONS

Although the independent mediator role of LM and %FM in the associations between CRF or MPO and bone mass was present during the prepubertal stage, only LM remain its mediator role in these associations during the postpubertal period. Therefore, with growth and sexual maturation, the full effect of LM seems to increase, whereas the influence of %FM seems to disappear.

Dietary nutrient intake of Korean adolescent distance runners

This study examined the dietary nutrient intake of Korean adolescent distance runners and analyzed the difference between weekdays and weekends. The participants were 40 male middle- and long-distance runners aged 13 to 18 years, 36 of whom were analyzed. The 3-day diet records including 2 weekdays and 1 weekend day, were investigated according to the food record method and analyzed using the computer-aided nutritional analysis program. A paired t-test was used to compare the energy and nutrient intakes of the weekdays and weekends, and the chi-square test was used to compare the distribution of the nutrient intake below the estimated average requirement. The results showed that the energy intake per day was quite low at 2,051.0±304.3 kcal, with a body mass index percentile of 16.8±9.8. The nutrients that showed remarkably lower levels than the dietary reference intakes for Koreans were vitamin D, vitamin C, vitamin B₂, and calcium, among which calcium was the highest at 86.1% in the proportion of those who consumed less than the estimated average requirement. The intakes of vitamin C and calcium, in particular, showed a significant decrease during the weekends. Therefore, to improve the dietary nutrient intake of adolescent male runners, appropriate management of the weekend diet as well as school meals should be considered.

Effect of Cdx2 Polymorphism on the Relationship between Dietary Calcium Intake and Peak Bone Mass in Young Japanese Women

Studies investigating the effect of the caudal-type homeobox protein 2 (Cdx2) polymorphism in the vitamin D receptor gene and calcium intake on bone mass have shown inconsistent results. This study investigated whether the effect of calcium intake on peak bone mass is affected by Cdx2 polymorphism in young Japanese women. A cross-sectional study of 500 young women was conducted. Dietary intake was assessed by the Food Frequency Questionnaire. The osteo sono-assessment index (OSI), assessed by the qualitative ultrasound method, was used as a bone mass index. The subjects were divided into two groups by the median calcium intake. The OSI was not different among Cdx2 genotypes and between calcium groups (p = 0.960, p = 0.191, respectively). The interaction between calcium and Cdx2 genotypes on the OSI approached significance (GG versus GA and AA genotypes, p = 0.092). The difference in the OSI between calcium groups was significant in the GG genotype (p = 0.028), but not in the GA or AA genotypes (p = 0.501, p = 0.306, respectively). Adjustment for covariates (body mass index and physical activity) did not change the results. In conclusion, the relationship between dietary calcium intake and peak bone mass may vary according to Cdx2 polymorphism.

Consumption of Greek yogurt during 12 weeks of high-impact loading exercise increases bone formation in young, adult males – a secondary analysis from a randomized trial

Exercise combined with protein and calcium has been shown to benefit bone turnover and bone metabolism. Greek yogurt (GY) contains important nutrients that support bone but has yet to be studied with exercise for this purpose. Thirty untrained, university-aged, males were randomized to 2 groups (n = 15/group): GY (20 g protein, 208 mg calcium/dose) or placebo pudding (PP; 0 g protein, 0 g calcium/dose) consumed 3×/day on training days and 2×/day on nontraining days. Both groups underwent a resistance/plyometric training program for 12 weeks. Blood was obtained at weeks 0, 1, and 12 to measure procollagen-type-I-N-terminal-propeptide (P1NP) and C-terminal-telopeptide (CTX). After outlier treatment, P1NP increased more over time in GY versus PP (p = 0.002; interaction). Both groups decreased CTX over time (p = 0.046; time effect). Following 1 week of training, there was a trend towards a significant increase in CTX in PP with no change in GY (p = 0.062; interaction). P1NP changed more in GY than PP (baseline to week 12; p = 0.029) as did the P1NP/CTX ratio (p = 0.015) indicating a greater increase in formation with GY. Thus, GY added to a high-load, high-impact exercise program positively shifted bone turnover towards increased formation while attenuating resorption. GY could be a plausible postexercise food to support bone health in young adult males.

Novelty Greek yogurt, with exercise, increased bone formation in young adult males over 12 weeks. After 1 week of an osteogenic exercise program, Greek yogurt tended to blunt a rise in bone resorption seen with the placebo. Greek yogurt is a plausible postexercise food that supports bone.

The Impact of Aerobic Exercise on Female Bone Health Indicators

Introduction:

Females usually suffer from bone health problems, particularly with aging. Aerobic exercise has been shown to have health benefits for females.

Aim:

The main objective of this study was to investigate the impact of aerobic exercise on female bone health by measuring serum trace elements and bone metabolism markers.

Methods:

Prospective interventional study was conducted at rehabilitation clinics in Royal Medical Services, Jordan. A total of 65 female participants were included. Participants were assigned into three groups: control group (N = 20), osteopenic group (N = 22), and osteoporotic group (N = 23). A standard aerobic exercise protocol was followed for 12 weeks. Endurance exercise protocol involved three sessions weekly for 60 minutes each. At basal level and after the experiment, the following parameters were assessed: body mass index (BMI), bone-specific alkaline phosphatase (BAP), T-score, bone mineral density (BMD), and calcium. The analysis of data was carried out using SPSS version 21. The difference in means was computed based on t-test. Significance was considered at p < 0.05.

Results:

Aerobic training exercise improved the levels of all parameters in all groups for both sexes significantly, including BMI, BAP, T-score, BMD, and calcium (p < 0.05).

Conclusion:

Aerobic training exercise improves bone health and restores the hemostasis of bone tissue by restoring bone biomarkers, including BAP and calcium.

External skeletal robustness and adiposity in adolescents of low socioeconomic status: A cross-sectional analysis of body composition

OBJECTIVES

External skeletal robustness has been decreasing in children, potentially due to a lack of physical activity and the increased prevalence of obesity. However, whether socioeconomic status (SES) influences external skeletal robustness in adolescents has not yet been examined.

METHODS

A cross-sectional study was performed to examine 370 Chilean adolescents (16.15 ± 1.01 years old) recruited from distinct educational establishments. Body fat percentage (BF%) was evaluated using Ellis' equations for Hispanic children. Obesity was defined as ≥25 BF% in males and ≥ 30 BF% in females. External skeletal robustness was obtained by measuring the humerus biepicondylar width and height (Frame-Index). SES was obtained through the ESOMAR survey.

RESULTS

Females exhibited significantly greater BF% and lower Frame-Index values than males (P < .001). Obese adolescents (by BF%) had greater Frame-Index values than non-obese adolescents (P < .001). Females of medium-high SES had significantly lower BF% and Frame-Index values than females of medium and medium-low SES. BF% had a positive correlation with Frame-Index values in all SES groups studied, except in males of medium-high SES. As SES decreased, the correlation increased in both sexes, but overall, the correlation was greater in females than males.

CONCLUSIONS

The results of this investigation suggest that obesity increases external skeletal robustness in adolescents. Additionally, lower SES corresponded to higher BF% and Frame-Index values. Therefore, modern conditions that influence the prevalence of obesity in adolescence could be affecting bone health in adolescents, primarily in females of medium-low SES.

Nutritional factors associated with femoral neck bone mineral density in children and adolescents

Background

Nutritional factors including vitamin D, magnesium, and fat are known to affect bone mineral accrual. This study aimed to evaluate associations between dietary nutrient intakes (both macronutrients and micronutrients) and bone mineral density (BMD) in children and adolescents.

Methods

Data for this cross-sectional, population-based study were derived from the National Health and Nutrition Examination Survey (NHANES). Participants aged from 8 to 19 years were included. The primary outcome was femoral neck BMD.

Results

Multivariate analyses revealed that for participants aged 8 to 11, daily sodium intake was significantly and positively associated with femoral neck BMD (B = 0.9 ×  10^− 5, p = 0.031); in particular, subgroup analyses by sex found that in male participants aged 8–11, daily total cholesterol intake (B = 5.3 × 10^− 5, p = 0.030) and calcium intake (B = − 2.0 × 10^− 5, p < 0.05) were significantly associated with femoral neck BMD in a positive and negative manner, respectively, but neither were observed in female participants of this age group. In contrast, daily intakes of vitamin D and magnesium were significantly and positively associated with femoral neck BMD in female participants aged 8–11 (B = 246.8 × 10^− 5 and 16.3 × 10^− 5, p = 0.017 and 0.033, respectively). For participants aged 16 to 19, daily total fat intake was significantly and negatively associated with femoral neck BMD (B = − 58 × 10^− 5, p = 0.048); further stratification by sex found that magnesium and sodium intakes were significantly and positively associated with femoral neck BMD only in females of this age group (B = 26.9 × 10^− 5 and 2.1 × 10^− 5, respectively; both p < 0.05). However, no significant associations between daily nutrient intakes and femoral neck BMD were identified in participants aged 12–15 before or after subgroup stratification.

Conclusion

The study found that associations of specific nutrition-related variables with BMD of the femoral neck is dependent upon age and gender.

Body Weight and Body Mass Index Influence Bone Mineral Density in Late Adolescence in a Two-Year Follow-Up Study. The Tromsø Study: Fit Futures

Determinants of bone acquisition in late adolescence and early adulthood are not well‐described. This 2‐year follow‐up study explored the associations of body weight (BW), body mass index (BMI), and changes in weight status with adolescent bone accretion in a sample of 651 adolescents (355 girls and 296 boys) between 15 and 19 years of age from The Tromsø Study: Fit Futures. This Norwegian population‐based cohort study was conducted from 2010 to 2011 and was repeated from 2012 to 2013. We measured femoral neck, total hip, and total body bone mineral content and areal bone mineral density (aBMD) by dual‐energy X‐ray absorptiometry. We measured height, BW, calculated BMI (kg/m ²), and collected information on lifestyle at both surveys. Mean BMI (SD) at baseline was 22.17 (3.76) and 22.18 (3.93) in girls and boys, respectively. Through multiple linear regression, baseline BW and BMI were positively associated with ∆aBMD over 2 years of follow‐up at all skeletal sites in boys ( p < 0.05), but not in girls. ∆BW and ∆BMI predicted ∆aBMD and ∆BMC in both sexes, but the strength of the associations was moderate. Individuals who lost weight during follow‐up demonstrated a slowed progression of aBMD accretion compared with those gaining weight, but loss of BW or reduction of BMI during 2 years was not associated with net loss of aBMD. In conclusion, our results confirm that adequate BW for height in late adolescence is important for bone health. Associations between change in weight status and bone accretion during follow‐up were moderate and unlikely to have any clinical implication on adolescents of normal weight. Underweight individuals, particularly boys, are at risk of not reaching optimal peak bone mass and could benefit from an increase in BMI. © 2019 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Association of objectively measured physical activity and sedentary behavior with bone stiffness in peripubertal children

INTRODUCTION

Physical activity (PA) is a key factor of bone mass acquisition in peripubertal children. Sedentary behavior (SB) has been shown to influence bone outcomes. This study aimed to examine the association between objectively measured PA and SB and bone stiffness in Japanese children.

MATERIALS AND METHODS

Participants were fifth-grade children aged 10-11 years from Project Koshu. The stiffness index (SI) of the calcaneus was measured by quantitative ultrasound; PA and SB were evaluated by an accelerometer. Each PA parameter was divided into sex-specific tertile or stratified by recommended PA guideline [≥ 60 min/day of moderate-to-vigorous PA (MVPA)]. The SI was compared among PA and SB through analysis of covariance with Bonferroni correction.

RESULTS

Of 174 children, complete data were obtained from 134 (60 boys and 74 girls). The SI in boys was higher in the highest tertile of MVPA than that in the other groups. A similar association was found in girls but was not significant. Children who met the PA guideline had higher SI than those who did not, but there was no significant difference. A negative relation was observed in girls, with the SI gradually decreasing along with increasing SB (p for trend = 0.038). This association was not observed among boys.

CONCLUSION

This study suggests that MVPA is positively associated with bone stiffness in Japanese schoolchildren in boys and SB is negatively associated with that in girls. Reducing SB might be a brief modifiable factor for preventing lower peak bone mass in girls, in addition to increasing MVPA.

Body Mass Index, Lean Mass, and Body Fat Percentage as Mediators of the Relationship between Milk Consumption and Bone Health in Young Adults

Identifying environmental factors that influence bone health is crucial for developing effective intervention strategies that maximize peak bone mass. The aim of this study was to estimate the relationship between milk consumption and bone mineral density (BMD) in young adults, and to examine whether this relationship is mediated by body mass index (BMI) and total lean and fat mass. A cross-sectional study involving college students (n = 239) from a Spanish public university was performed. Data on milk consumption and anthropometric and body composition variables were collected. The Pearson correlation coefficients among total body BMD, body composition variables, and milk consumption ranged from -0.111 to -1.171, most of them statistically significant (p < 0.05). The ANCOVA (analysis of covariance) models showed that those with higher regular milk consumption had less total body BMD than those with lower regular milk consumption (p < 0.05), even after controlling for different sets of confounders. In the mediation analysis, BMI and lean and fat mass turned out to act as full mediators of the relationship between regular milk consumption and total body BMD (z = -1.7148, -1.3208, and -1.8549, respectively; p ≤ 0.05). In conclusion, milk consumption, per se, does not seem to have a direct effect on bone development, because its association seems to be fully mediated by body composition variables in young adults.

Bone mineral density and bone mineral content among female elite athletes

INTRODUCTION

Exercise is a protective factor for the appearance of osteoporosis, but not all physical activities have the same effect on bones. Low-impact sports, like swimming, may a have a negative or no effect. The aim of the present study is to evaluate bone mineral density (BMD, g/cm²) and bone mineral content (BMC, kg) among female high performance athletes from aquatic and non-aquatic sports and to assess possible differences with sedentary controls.

METHODS

Participants are elite female athletes over 18 years, from the Spanish Olympic teams, with at least 12-15 h of weekly training on aquatic sports: swimming (n = 19), synchronized swimming (n = 24) and water polo (n = 14), and elite female athletes from non-aquatic sports: professional football players of Futbol Club Barcelona team (n = 92), Spanish national volleyball (n = 26) and field hockey teams (n = 29) as well as sedentary controls (n = 126). Bone mineral density scans was performed using dual-energy X-ray absorptiometry for whole body, segmental analysis, proximal femur and lumbar spine.

RESULTS

Non-aquatic female athletes have total and segments BMC and BMD values higher than those of aquatic athletes, that in turn show similar BMD values compared to controls. BMD in lumbar spine and proximal femur was higher in non-aquatic sports compared to aquatic sports athletes and both were higher than controls.

CONCLUSION

BMD is not negatively compromised by the practice of aquatic sports at a highly competitive level. However, non-aquatic female athletes show a higher BMD. Time training out of the water improves BMD. Our findings suggest that swimming and synchronized swimming should be combined with weight-bearing, impact or strength activities, as they do not seem to be osteogenic sports.

Does peak bone mass correlate with peak bone strength? Cross-sectional normative dual energy X-ray absorptiometry data in 1052 men aged 18-28 years

Background

Areal bone mineral density (aBMD) estimated by dual-energy X-ray absorptiometry (DXA) is used to estimate peak bone mass, define osteoporosis and predict fracture. However, as aBMD is calculated as bone mineral content (BMC) divided by the scanned area, aBMD displays an inverse relationship with bone size. In a skeleton that is increasing in size, this is a problem, as bone size is an independent factor that determines bone strength. It could therefore be questioned whether peak aBMD is the period with greatest bone strength, a period that in the hip then would occur in ages 16–19. The aim of this study was to evaluate whether there are changes in bone size in men after age 18 that may influence peak bone strength. Another aim was to provide updated normative DXA data.

Methods

We scanned left femoral neck by DXA in a cross-sectional study with a population-based selection of 1052 men aged 18–28, and then registered bone mineral content (BMC, gram), aBMD (gram/cm²) and bone area (cm²) in each one-year age group. We performed analyses of variance (ANOVA) to evaluate whether there were differences in these traits between the age groups. We then used Pearson’s correlation analyses to test for trends with ageing after peak bone mass was reached.

Results

We found the highest absolute femoral neck aBMD at age 19, with statistically significant differences between the one-year age groups in BMC, aBMD, and bone area (all p < 0.05). From peak bone mass onwards (n = 962), there are negative correlations between age and BMC (r = − 0.07; p < 0.05) and age and aBMD (r = − 0.12; p < 0.001), and positive correlation between age and bone area (r = 0.06; p < 0.05).

Conclusion

As femoral neck bone size in young adult men becomes larger after peak bone mass, it could be questioned whether DXA estimated peak aBMD correlates with peak bone strength. We infer that aBMD must be interpreted with care in individuals with a growing skeleton, since skeletal strength may then increase, in spite of decreasing aBMD. This should be taken into account when performing DXA measurements in these ages.

One-year adolescent bone mineral density and bone formation marker changes through the use or lack of use of combined hormonal contraceptives

OBJECTIVE

The objective of this study was to evaluate the effects of two low-dose combined oral contraceptives on bone metabolism in adolescents for one year.

METHODS

This was a quasi-experimental study. The adolescents were divided into three groups: oral contraceptives 1 (n=42) (20μg EE/150μg desogestrel), oral contraceptives 2 (n=66) (30μg EE/3mg drospirenone), and a control group (n=70). Adolescents underwent anthropometric assessment and densitometry (dual-energy X-ray). Bone age and bone formation markers (osteocalcin and bone alkaline phosphatase) were evaluated. The oral contraceptives users were evaluated again after 12 months. Linear regression analysis was used to indirectly study the effect of each additional year of chronological age on anthropometric and densitometric variables as well as on bone markers in the control group.

RESULTS

At study entry, no significant differences were observed between the oral contraceptives 1, oral contraceptives 2, and controls in the analyzed variables. Linear regression analysis showed an increase in bone mineral density and bone mineral content for each additional year. There was a significant reduction in bone alkaline phosphatase levels; no significant difference was observed for osteocalcin in control individuals. Comparison of dual-energy X-ray variables at baseline and after one year showed no significant differences in the oral contraceptives 1 or oral contraceptives 2 groups. A significant reduction in bone alkaline phosphatase and osteocalcin levels was observed in both the oral contraceptives 1 and oral contraceptives 2 groups.

CONCLUSION

Adolescent women gain peak bone mass during this phase of life. Two low-dose combined oral hormonal contraceptives were associated with lower bone gain and lower bone formation markers than in untreated controls.

Gender affirming medical care of transgender youth

The number of gender diverse and transgender youth presenting for treatment are increasing. This is a vulnerable population with unique medical needs; it is essential that all pediatricians attain an adequate level of knowledge and comfort caring for these youth so that their health outcomes may be improved. There are several organizations which provide clinical practice guidelines for the treatment of transgender youth including the WPATH and the Endocrine Society and they recommend that certain eligibility criteria should be met prior to initiation of gender affirming hormones. Medical intervention for transgender youth can be broken down into stages based on pubertal development: pre-pubertal, pubertal and post-pubertal. Pre-pubertally no medical intervention is recommended. Once puberty has commenced, youth are eligible for puberty blockers; and post-pubertally, youth are eligible for feminizing and masculinizing hormone regimens. Treatment with gonadotropin releasing hormone agonists are used to block puberty. Their function is many-fold: to pause puberty so that the youth may explore their gender identity, to delay the development of (irreversible) secondary sex characteristics, and to obviate the need for future gender affirmation surgeries. Masculinizing hormone regimens consists of testosterone and feminizing hormone regimens consist of both estradiol as well as spironolactone. In short term studies gender affirming hormone treatment with both estradiol and testosterone has been found to be safe and improve mental health and quality of life outcomes; additional long term studies are needed to further elucidate the implications of gender affirming hormones on physical and mental health in transgender patients. There are a variety of surgeries that transgender individuals may desire in order to affirm their gender identity; it is important for providers to understand that desire for medical interventions is variable among persons and that a discussion about individual desires for surgical options is recommended.