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Background: Exercise optimizes peak bone mass accrual, particularly if the loading is high magnitude and distributed in abnormal directions. Little is known about the influence of early intense training in sport during peak bone mass accrual, especially in boys. Methods: Ninety-eight males aged 6–24 years (gymnasts, swimmers, and controls) completed the bone-specific physical activity questionnaire and a 7-day exercise diary. Dual-energy X-ray absorptiometry determined bone mineral properties of the total body (less head) and lumbar spine (LS, L1–L4) and total lean mass. Subgroup analyses were conducted for juniors (prepubescent), adolescents (11–16 y), and seniors (17–24 y). Results: Lean mass was positively associated with total body less head and LS bone outcomes in all 3 age groups (R2 =.632–.770, P <.05), and bone-specific physical activity questionnaire scores were associated with LS bone mineral density in adolescents and seniors (R2 =.440 and.591, P <.05). Senior gymnasts had significantly higher LS bone mineral density (in grams per square centimeter) and Z-scores than swimmers (P =.004) and controls (P =.012). Conclusions: Elite gymnastics is associated with superior peak bone mass accrual in young males. The benefits appear more pronounced during young adulthood compared with prepuberty, potentially reflecting an extended time course for bone adaptation. [ABSTRACT FROM AUTHOR]

Weight-bearing physical activity is considered beneficial to bone health throughout the course of life, with the most marked benefits for bone health often considered to be high levels of activity around the time of peak bone mass (PBM) acquisition. To date, the research focus has been on the benefits of recreational weight-bearing sporting activity. Participation in elite sport is associated with enhanced sporting activity but is often also associated with low body weight, menstrual disturbance in females, and rest periods following injury. The benefit of sporting activity may, therefore, be attenuated in these groups. Here, we undertook a systematic review to consider what evidence is available regarding whether elite sporting activity in young adulthood has lasting benefits for bone health. Studies of retired athletes aged >50 years, who participated in elite sport from 15 to 30 years, were considered for inclusion. Elite sport was defined as participation at the national level or above. Following protocol development, the search strategy was applied to PubMed, Medline, Embase, and Web of Science. The selection was managed with Rayyan software, and the bias was assessed using the Newcastle–Ottawa scale. Two reviewers independently identified papers; a third adjudicated and screened the final selection for consideration. The protocol was registered with PROSPERO (CRD42021293644). Two reviewers screened 951 articles, of which 4 papers met the inclusion criteria. One paper reported findings in women and three in men; no paper included both sexes. The sample sizes varied from 24 to 193 and considered football, endurance running, weightlifting, and swimming. Bone density was measured at the femoral neck, trochanter, and lumbar spine. All studies reported higher density in former athletes than non-elite controls, though the information available regarding confounding lifestyle factors was variable. A meta-analysis was not possible as studies were too heterogenous. In conclusion, from the limited available evidence, our study suggests elite sporting activity in young adulthood may have lasting benefits for bone health. However, given the paucity of available data, we highlight an urgent need for future research, especially in female athletes. [ABSTRACT FROM AUTHOR]

Weight-bearing physical activity is considered beneficial to bone health throughout the course of life, with the most marked benefits for bone health often considered to be high levels of activity around the time of peak bone mass (PBM) acquisition. To date, the research focus has been on the benefits of recreational weight-bearing sporting activity. Participation in elite sport is associated with enhanced sporting activity but is often also associated with low body weight, menstrual disturbance in females, and rest periods following injury. The benefit of sporting activity may, therefore, be attenuated in these groups. Here, we undertook a systematic review to consider what evidence is available regarding whether elite sporting activity in young adulthood has lasting benefits for bone health. Studies of retired athletes aged >50 years, who participated in elite sport from 15 to 30 years, were considered for inclusion. Elite sport was defined as participation at the national level or above. Following protocol development, the search strategy was applied to PubMed, Medline, Embase, and Web of Science. The selection was managed with Rayyan software, and the bias was assessed using the Newcastle–Ottawa scale. Two reviewers independently identified papers; a third adjudicated and screened the final selection for consideration. The protocol was registered with PROSPERO (CRD42021293644). Two reviewers screened 951 articles, of which 4 papers met the inclusion criteria. One paper reported findings in women and three in men; no paper included both sexes. The sample sizes varied from 24 to 193 and considered football, endurance running, weightlifting, and swimming. Bone density was measured at the femoral neck, trochanter, and lumbar spine. All studies reported higher density in former athletes than non-elite controls, though the information available regarding confounding lifestyle factors was variable. A meta-analysis was not possible as studies were too heterogenous. In conclusion, from the limited available evidence, our study suggests elite sporting activity in young adulthood may have lasting benefits for bone health. However, given the paucity of available data, we highlight an urgent need for future research, especially in female athletes.

Background: There is limited research providing an overall understanding of bone mineral density (BMD) changes throughout different stages of life. This study aimed to investigate the pattern of BMD changes across childhood, adolescence, adulthood, and old age, as well as exploring the critical time of peak BMD (PBMD). Methods: Participants of three major ethnicities from National Health and Nutrition Examination Survey 1999 to 2018 were involved: 46,381 and 20,944 participants aged 8–85 years old were included in the Lumbar spine BMD (LSBMD) and femoral neck BMD (FNBMD) studies, respectively. BMD was measured using dual-energy X-ray absorptiometry. The generalized additive model was used to construct smoothed percentile curves. Results: Both males and females experienced a sharp increase in LSBMD during puberty, with females reaching their PBMD earlier than males. Females' LSBMD remained higher than males' before the age of approximately 50, except for Non-Hispanic Blacks. For males, LSBMD reached a plateau at around 30 years old after reaching the peak value. Females exhibited two peak points on the fitted curves, with the second PBMD occurring around 36–37 years old. Ethnic variations were observed, with Non-Hispanic Blacks displaying the highest BMD levels at all ages. Non-Hispanic Whites and Mexican Americans had lower BMD levels, with Mexican Americans generally exhibiting the lowest BMD. FNBMD reached its peak earlier than LSBMD, and males consistently had higher FNBMD than females. Conclusions: This nationally representative study contributes to the understanding of BMD changes across the lifespan, and might provide guidance for bone health interventions in different population groups. [ABSTRACT FROM AUTHOR]

Summary: In a Norwegian youth cohort followed from adolescence to young adulthood, bone mineral density (BMD) levels declined at the femoral neck and total hip from 16 to 27 years but continued to increase at the total body indicating a site-specific attainment of peak bone mass. Purpose: To examine longitudinal trends in bone mineral density (BMD) levels in Norwegian adolescents into young adulthood. Method: In a prospective cohort design, we followed 980 adolescents (473 (48%) females) aged 16–19 years into adulthood (age of 26–29) on three occasions: 2010–2011 (Fit Futures 1 (FF1)), 2012–2013 (FF2), and 2021–2022 (FF3), measuring BMD (g/cm2) at the femoral neck, total hip, and total body with dual x-ray absorptiometry (DXA). We used linear mixed models to examine longitudinal BMD changes from FF1 to FF3. Results: From the median age of 16 years (FF1), femoral neck BMD (mean g/cm2 (95% CI)) slightly increased in females from 1.070 (1.059–1.082) to 1.076 (1.065–1.088, p = 0.015) at the median age of 18 years (FF2) but declined to 1.041 (1.029–1.053, p < 0.001) at the median age of 27 years (FF3). Similar patterns were observed in males: 16 years, 1.104 (1.091–1.116); 27 years, 1.063 (1.050–1.077, p < 0.001); and for the total hip in both sexes (both p < 0.001). Total body BMD increased from age 16 to 27 years in both sexes (females: 16 years, 1.141 (1.133–1.148); 27 years, 1.204 (1.196–1.212), p < 0.001; males: 16 years, 1.179 (1.170–1.188); 27 years, 1.310 (1.296–1.315), p < 0.001). Conclusion: BMD levels increased from 16 to 18 years at the femoral and total hip sites in young Norwegian females and males, and a small decline was observed at the femoral sites when the participants were followed up to 27 years. Total body BMD continued to increase from adolescence to young adulthood. [ABSTRACT FROM AUTHOR]

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The main aim of this study was to compare bone health parameters in young active sprinters and young active men. Twenty-six young sprinters and 26 young men participated in this study. Weight and height were measured, and body mass index (BMI) was calculated. Body composition, whole body (WB) BMC, lumbar spine (L1–L4) BMD, total hip (TH) BMD and forearm BMD were evaluated by DXA. Physical performance variables, daily calcium intake, daily protein intake and physical activity level were assessed. Age, height, lean mass, WB BMC and forearm BMD were not significantly different between the two groups. L1–L4 BMD, TH BMD, vertical jump and maximal strength of the lower limbs were higher in sprinters compared to active men. The current study suggests that sprinters have higher lumbar spine and hip BMD values compared to active men. The current study has several implications in the field of prevention of osteoporosis in men. [ABSTRACT FROM AUTHOR]

ABSTRACT: Bone mass attained early in life is one of the most important determinants of lifelong skeletal health. Bone mineral content increases exponentially during childhood. In fact, 40%-60% of the total adult bone mass is accrued during puberty. By the end of the first 2 decades of life, peak bone mass has been reached. Between ages 20-50, bone mass has plateaued, but it continues to remodel. This is regulated by parathyroid hormone (PTH), vitamin D3, and insulin-like growth factor 1 (IGF-1). After the age of 50, bone mass begins to decrease. The purpose of this paper is to review the importance of maximizing peak bone mass and factors that can modify and maintain peak bone mass. Key Concepts: (1) Peak bone mass is attained by the end of the second decade of life. (2) There are more fractures during peak height velocity in adolescence as the body increases in size but bone mineralization lags behind. (3) The risk of adult osteoporosis starts in childhood. (4) There are modifiable and nonmodifiable risk factors that affect peak bone mass. Level of Evidence: IV

Estrogen is critical for bone health from puberty onwards. Various clinical scenarios in adolescence can impact skeletal exposure to estrogen during this vulnerable time. Primary ovarian insufficiency, premature menopause, and anorexia nervosa necessitate prompt evaluation, treatment, and replacement of estrogen in order to optimize accrual of peak bone mass. We have much still to learn about the skeletal impact of delaying puberty and gender affirming hormones in gender diverse individuals. While the choice of hormonal contraception in adolescence is often driven by patient preference and concerns about adherence, providers and patients much take the long-term impact on bone health into consideration. Key Concepts: (1) Delayed, diminished or absent estrogen during adolescence has a negative impact on peak bone mass accrual. (2) Hormone replacement therapy is essential for patients with primary ovarian insufficiency and premature menopause. (3) Recovery from anorexia nervosa does not lead to a complete catch-up of bone density lost/not gained. (4) Not all hormonal contraception methods are created equal for the adolescent skeleton. (5) Skeletal health of trans youth is an emerging focus.

Peak bone mass is the amount of bone tissue that is formed when a stable skeletal state is achieved at a young age. To date, there are no established peak bone mass standards nor clear data on the age at which peak bone mass occurs. At the same time, the level of peak bone mass at a young age is an important predictor of the onset of primary osteoporosis. The purpose of this review is to analyze the results of studies of levels of peak bone mass in general, the age of its onset, as well as factors influencing its formation. Factors such as hormonal levels, body composition, physical activity, nutrition, heredity, smoking, lifestyle, prenatal predictors, intestinal microbiota, and vitamin and micronutrient status were considered, and a comprehensive scheme of the influence of these factors on the level of peak bone mass was created. Determining the standards and timing of the formation of peak bone mass, and the factors affecting it, will help in the development of measures to prevent its shortage and the consequent prevention of osteoporosis and concomitant diseases. [ABSTRACT FROM AUTHOR]

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The aim of the current study was to investigate the relationships between relative strength of the lower limbs and composite indices of femoral neck strength (compression strength index [CSI], bending strength index [BSI] and impact strength index [ISI]) in a group of young adult men. In all, 54 Lebanese young men whose ages range from 20 to 30 years (24.4 ± 3.1 years) participated in our study. Body composition and hip bone mineral density were assessed by DXA. CSI, BSI and ISI were calculated. One-repetition maximum (1-RM) half-squat, 1-RM deadlift and 1-RM bench-press were measured. 1-RM half-squat/body mass was positively correlated to CSI (r = 0.35; P < 0.01), BSI (r = 0.33; P < 0.05) and ISI (r = 0.32; P < 0.05), but negatively correlated to fat mass percentage (r = −0.37; P < 0.01). The current study suggests that relative muscular strength of lower limbs is positively correlated to composite indices of femoral neck strength in young men. [ABSTRACT FROM AUTHOR]

Weight-bearing exercise (WBE) has been identified as an appropriate approach for increasing peak bone mass, however, there is a lack of specific physical activity recommendations in this area. Thus, the aim of this systematic review is to determine the optimal mode of WBE, specifically identifying the intensity, duration, frequency, and load, to elicit the optimal effect on bone mass in young females, aged 5-18. A literature search was conducted from the 28th of June to the 20th of July 2021 using PubMed/Medline, Web of Science and SPORTDiscus. The search produced 1405 results, of which 15 were deemed appropriate for inclusion. The majority of studies (n=12) found a significant positive effect for at least one bone measure through their respective WBE exposure (p<0.05). Bone mass accrual was found to be site-specific depending on WBE exposure type, load, and maturity status. Also, longitudinal effects on bone mass accrual were found exclusively in gymnastics participants, even if participation level decreased (i.e., retirement). The results of this study support the use of WBE to improve parameters of bone health. However, further research is needed as the optimal mode of WBE to elicit the optimal effect on bone mass is still unclear. [ABSTRACT FROM AUTHOR]

Aim: This study examined the influence of body composition and physical activity level (PAL) on bone mineral density (BMD) to determine the baseline values necessary for maintaining healthy trabecular bone and improving bone health in young women. Materials and Methods: The subjects, consisting of healthy young women, were assigned to either a BMD-low (BMD-L) or BMD-high (BMD-H) group using the osteosonic index. PAL was measured for 1 week and rated on a scale from PAL-1 to 8 according to intensity levels (metabolic equivalents [METs]). The Wilcoxon rank-sum test was performed for intergroup comparisons. Results: The BMD-H group had significantly higher fat-free muscle mass, skeletal muscle index, and basic metabolic rate than the BMD-L group (p?0.001, each). Regarding the timing of physical activity in daily life according to intensity, PAL-6 (p?

Peak bone mass is the amount of bone tissue that is formed when a stable skeletal state is achieved at a young age. To date, there are no established peak bone mass standards nor clear data on the age at which peak bone mass occurs. At the same time, the level of peak bone mass at a young age is an important predictor of the onset of primary osteoporosis. The purpose of this review is to analyze the results of studies of levels of peak bone mass in general, the age of its onset, as well as factors influencing its formation. Factors such as hormonal levels, body composition, physical activity, nutrition, heredity, smoking, lifestyle, prenatal predictors, intestinal microbiota, and vitamin and micronutrient status were considered, and a comprehensive scheme of the influence of these factors on the level of peak bone mass was created. Determining the standards and timing of the formation of peak bone mass, and the factors affecting it, will help in the development of measures to prevent its shortage and the consequent prevention of osteoporosis and concomitant diseases.

The aim of the current study was to evaluate the effects of different levels of weightlifting training on bone mineral density (BMD) at different body sites (whole body (WB), lumbar spine (LS), femoral neck (FN), upper limbs (UL) and lower limbs (LL)) in a group of adolescents. Three groups of pubertal boys aged 13-15 years were recruited, including a control group (which included 13 untrained adolescents), a moderately trained group (which included 13 non-elite weightlifters, with four sessions of 2 hours per week) and a highly trained group (which included 13 elite weightlifters, with eight sessions of 2 hours per week). The three groups were paired for age and maturation index (using Tanner stages). Body composition, bone mineral content (BMC) and BMD were evaluated by dual-energy X ray absorptiometry (DXA). Physical performance variables (including weightlifting specific exercises, counter movement jump and squat jump) were measured using validated methods. Results showed that the values of BMD and physical performance variables were greater in the group of elite weightlifters compared to the group of non-elite weightlifters and the control group. In addition, the values of BMD and physical performance variables were higher in the group of the non-elite weightlifters compared to those of the control group. After adjusting for lean mass and squat jump, lumbar spine BMD, FN BMD, UL BMD and LL BMD remained significantly higher in the elite weightlifters' group compared to the two other groups. In conclusion, the current study suggests that elite adolescent weightlifters have greater bone health parameters compared to moderately-trained adolescent weightlifters and untrained adolescents. [ABSTRACT FROM AUTHOR]

Background: The effect of calcium supplementation on bone mineral accretion in people under 35 years old is inconclusive. To comprehensively summarize the evidence for the effect of calcium supplementation on bone mineral accretion in young populations (≤35 years). Methods: This is a systematic review and meta-analysis. The Pubmed, Embase, ProQuest, CENTRAL, WHO Global Index Medicus, Clinical Trials.gov, WHO ICTRP, China National Knowledge Infrastructure (CNKI), and Wanfang Data databases were systematically searched from database inception to April 25, 2021. Randomized clinical trials assessing the effects of calcium supplementation on bone mineral density (BMD) or bone mineral content (BMC) in people under 35 years old. Results: This systematic review and meta-analysis identified 43 studies involving 7,382 subjects. Moderate certainty of evidence showed that calcium supplementation was associated with the accretion of BMD and BMC, especially on femoral neck (standardized mean difference [SMD] 0.627, 95% confidence interval [CI] 0.338–0.915; SMD 0.364, 95% CI 0.134–0.595; respectively) and total body (SMD 0.330, 95% CI 0.163–0.496; SMD 0.149, 95% CI 0.006–0.291), also with a slight improvement effect on lumbar spine BMC (SMD 0.163, 95% CI 0.008–0.317), no effects on total hip BMD and BMC and lumbar spine BMD were observed. Very interestingly, subgroup analyses suggested that the improvement of bone at femoral neck was more pronounced in the peripeak bone mass (PBM) population (20–35 years) than the pre-PBM population (

To identify the differences of biomarkers between high and low peak bone mass population, and their value in the diagnosis and treatment of osteoporosis. Methods The gene expression dataset ( GSE7158) of high and low peak bone mass population was obtained from GEO database. The differentially expressed genes were analyzed with limma package in R. Then GO functional annotation and KEGG pathway enrichment analysis were performed. All differential genes were input into the STRING database to obtain the protein-protein interaction (PPI) network. Cytohubba plug-in in Cytoscape and R was used to identify key genes and their interaction network was further mapped by Cytoscape. Finally, further verification of the expression and diagnostic value of key genes in osteoporosis was performed. Results A total of 182 differentially expressed genes were screened in high and low peak bone mass population, among which 73 were down-regulated, and 109 were up-regulated. KEGG pathway analysis showed that osteoclast differentiation pathway, PI3K-Akt signaling pathway, and AGE-RAGE signaling pathway in diabetic complications and ferroptosis were worthy of attention. PPI network analysis revealed 11 key genes : MCM7, Bub3, RBBP7, GNG2, FSHR, PCNA, CCR5, CDK16, SRSF7, NPMl, and CPSF6. Further validation analysis found that CCR5, CDK16, RBBP7, and SRSF7 were closely related to osteoporosis. Conclusion CCR5, CDK16, RBBP7, and SRSF7 may be closely related to the incidence of osteoporosis, and may become biomarkers for early screening of people at high risk of osteoporosis. This provides an effective basis for further experimental research and clinical treatment. [ABSTRACT FROM AUTHOR]

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Bone mass in adulthood depends on growth and mineralization acquired during childhood and adolescence. It is well known that these stages of life are crucial for bone development, where genetic, nutritional, hormonal, and lifestyle factors play a significant role. Bone loss is normally a natural and slow process that begins years later after the peak bone mass is achieved and continues throughout the lifespan. Lifestyle choices in childhood and adolescence such as minimal physical activity, excessive caffeine or carbonated beverages intake, malnutrition, cigarette use, or high alcohol consumption and other factors like environmental pollutants can also negatively affect bone health and accelerate the bone loss process. The aim of this work is an overview of risk factors associated with inadequate bone health in early life. [ABSTRACT FROM AUTHOR]

Summary: Ground impacts during physical activity may be important for peak bone mass. We found differences in how energy expenditure and impact scores estimated from a physical activity questionnaire related to bone health in young adults. Using both estimate types can improve our understanding of the skeletal benefits of physical activity. Purpose: It is unclear whether mechanical loading during physical activity, estimated from physical activity questionnaires which assess metabolic equivalents of task (METs), is associated with skeletal health. This longitudinal study investigated how physical activity loading scores, assessed at ages 17 and 20 years, (a) compares with physical activity measured in METs, and (b) is associated with bone mass at age 20 years. Methods: A total of 826 participants from the Raine Study Gen2 were assessed for physical activity energy expenditure via the International Physical Activity Questionnaire (IPAQ) at age 17 and 20 years. Loading scores (the product of peak force and application rate) per week were subsequently estimated from the IPAQ. Whole-body and appendicular bone mineral density (BMD) at age 20 years were assessed by dual-energy X-ray absorptiometry. Results: Bland–Altman minimal detectable difference for physical activity Z- scores at age 17 and 20 years were 1.59 standard deviations (SDs) and 1.33 SDs, respectively, greater than the a priori minimal clinically important change of 0.5 SDs. Loading score, but not IPAQ score, had significant positive associations with whole-body and leg BMD after adjustment for covariates (β = 0.008 and 0.012 g/cm2, respectively, for age 17 and 20 years loading scores). IPAQ score at age 20 years, but not loading score, had a significant positive association with arm BMD (β = 0.007 g/cm2). Conclusion: This study revealed disagreement in associations of self-reported METs and loading score estimates with bone health in young adults. Coupling traditional energy expenditure questionnaire outcomes with bone-loading estimates may improve understanding of the location-specific skeletal benefits of physical activity in young adults. [ABSTRACT FROM AUTHOR]

Catch-up growth is a process that promotes weight and height gains to recover normal growth patterns after a transient period of growth inhibition. Accelerated infant growth is associated with reduced bone mass and quality characterized by poor bone mineral density (BMD), content (BMC), and impaired microarchitecture. The present study evaluated the effects of a diet containing slow (SDC) or rapid (RDC) digestible carbohydrates on bone quality parameters during the catch-up growth period in a model of diet-induced stunted rats. The food restriction period negatively impacted BMD, BMC, and microarchitecture of appendicular and axial bones. The SDC diet was shown to improve BMD and BMC of appendicular and axial bones after a four-week refeeding period in comparison with the RDC diet. In the same line, the micro-CT analysis revealed that the trabecular microarchitecture of tibiae and vertebrae was positively impacted by the dietary intervention with SDC compared to RDC. Furthermore, features of the cortical microstructure of vertebra bones were also improved in the SDC group animals. Similarly, animals allocated to the SDC diet displayed modest improvements in growth plate thickness, surface, and volume compared to the RDC group. Diets containing the described SDC blend might contribute to an adequate bone formation during catch-up growth thus increasing peak bone mass, which could be linked to reduced fracture risk later in life in individuals undergoing transient undernutrition during early life. [ABSTRACT FROM AUTHOR]

Nutrition is an important determinant of bone health and attainment of peak bone mass. Diets containing dried plum (DP) have been shown to increase bone volume and strength. These effects may be linked to the immune system and DP-specific polyphenols. To better understand these relationships, we studied DP in skeletally mature (6-month-old) and growing (1- and 2-month-old) C57Bl/6 male mice. In adult mice, DP rapidly (

The foundation of bone health is established in utero. Bone accrual starts from the developing fetus and continues throughout childhood and adolescence. This process is crucial to achieve peak bone mass. Understanding factors that influence bone accrual before attainment of peak bone mass is thus critical to improve bone health and prevent osteoporosis, thereby reducing the burden of osteoporotic fractures in older women. In this review, we broadly outline factors influencing peak bone mass from pregnancy to infancy, childhood and adolescence with potential diseases and medications that may affect the optimum trajectory to maximizing bone health. It is estimated that a 10% increase in peak bone mass will delay the onset of osteoporosis by 13 years in a woman. [ABSTRACT FROM AUTHOR]

Summary: Dairy products are essential to ensure calcium recommendations to achieve optimal peak bone mass and avoid bone loss. However, high prevalence of lactose malabsorption decreases milk‐derived foods consumption. The use of β‐galactosidase, which hydrolyses lactose to galactooligosaccharides (GOS) is an alternative to develop a low‐lactose yoghurt (EY) where prebiotics (GOS) and probiotics (Lactobacilli) coexist. The effects of two diets based on EY or standard yoghurt without GOS (Y) on calcium absorption and bone retention were evaluated and compared, in growing rats. Control group received AIN 93‐G diet. Male weaning rats were fed one of these three diets for 28 days. EY group showed the highest increase in faecal Lactobacillus colonies, in short‐chain fatty acids production, in intestinal crypt deep, and the lowest caecum pH. Calcium absorption (%) increased significantly as follows: EY>Y>control (P < 0.05). EY and control showed similar calcium content in femur, bone mineral content and density, and total epiphyseal cartilage while Y showed the lowest value (P < 0.05). Conclusion: YE presented some advantages compared to Y regarding calcium absorption and bone retention since Y could not match bone growth and quality of control group. EY was an effective low lactose‐dairy product for delivering prebiotics and probiotics into gut, to enhance gut health and calcium bioavailability that improved bone development in a period of high calcium requirements as growth stage. Even more important is that EY could represent an efficient therapeutic strategy to achieve calcium recommendations in people who avoid dairy product consumption due to unpleasant symptoms of lactose intolerance. [ABSTRACT FROM AUTHOR]

Abstract Background Intensity of resistance training history might be omitted or poorly ascertained in prescreening or data questionnaires involving musculoskeletal health. Failure to identify history of high-versus low-intensity training may overlook higher effect sizes with higher intensities and therefore diminish the precision of statistical analysis with resistance training as a covariate and bias the confirmation of baseline homogeneity for experimental group designation. The purpose was to determine the degree to which a single question assessing participant history of resistance training intensity predicted differences in musculoskeletal health. Methods In the first research aim, participants were separated into groups with a history (RT) and no history (NRT) of resistance training. The second research aim evaluated the history of resistance training intensity on muscular strength, lean mass, and bone mineral density (BMD), RT participants were reassigned into a low- (LIRT) or high-intensity resistance training group (HIRT). 83 males and 87 females (19.3 ± 0.6 yrs., 171.1 ± 9.9 cm, 67.1 ± 10.5 kg, 22.9 ± 2.8 BMI, 26.2 ± 7.2% body fat) completed handgrip dynamometry (HG) and dual-energy x-ray absorptiometry scans (DXA) for BMD and bone mineral-free lean mass (BFLM). Results A 3-group method (NRT, LIRT, HIRT) reduced type-I error compared with the 2-group method (NRT, RT) in characterizing the likely effects of one’s history of resistance training. For the second aim, HIRT had significantly (p

Maximizing accumulation of bone mass during childhood and adolescence is essential to attaining optimal peak bone mass. Childhood cancer survivors (CCS) have lower bone mineral density (BMD) than the general population. Chemotherapeutic agents including steroids and radiotherapy can affect BMD. Cancer itself, hormonal insufficiency, a poor nutritional state, and a deficit of physical activities during or after treatment also influence BMD in CCS, resulting in failure to achieve appropriate peak bone mass. Low BMD in childhood and adolescence can lead to osteoporosis in adult life and complications such as bone pain, bone deformity, and fractures. Thus, BMD in CCS should be monitored with appropriate intervention. Adequate intake of calcium and vitamin D and an increase in physical activity are recommended. Timely supplements of hormones are needed in some cases. Some publications have reported that bisphosphonate therapies using pamidronate or alendronate were well tolerated in CCS and helped increase BMD.

PURPOSE An increase in bone mineral density during adolescence increases resistance to fractures in older age. The Korean Society for Bone and Mineral Research and the Korean Society of Exercise Physiology developed exercise guidelines to increase the peak bone mass (PBM) in adolescents based on evidence through a systematic review of previous research. METHODS Articles were selected using the systematic method, and the exercise guidelines were established by selecting key questions (KQs) and defining the effects of exercises based on evidence through a literature review for selecting the final exercise method. There were 9 KQs. An online search was conducted on articles published since 2000, and 93 articles were identified. RESULTS An increase in PBM in adolescence was effective for preventing osteoporosis and fractures in older age. Exercise programs as part of vigorous physical activity (VPA) including resistance and impact exercise at least 5 to 6 months were effective for improving PBM in adolescents. It is recommended that resistance exercise is performed 10 to 12 rep·set-1 1-2 set·region-1 and 3 days·week-1 using the large muscles. For impact exercises such as jumping, it is recommended that the exercise is performed at least 50 jumps·min-1, 10 min·day-1, and 2 days·week-1. CONCLUSIONS Exercise guidelines were successfully developed, and they recommend at least 5 to 6 months of VPA, which includes both resistance and impact exercises. With the development of exercise guidelines, the incidence of osteoporosis and fractures in the aging society can be reduced in the future, thus contributing to improved public health.

Modification of bone is continuous throughout life and influenced by many factors, including physical activity. This study investigated changes in areal bone mineral density (aBMD) and hip structure among male and female collegiate distance runners and non-athlete controls over 12 months. Using dual-energy x-ray absorptiometry (DXA) and hip structure analysis (HSA) software, aBMD at the posterior-anterior (PA) and lateral spine, femoral neck, total hip (TH), whole body (WB), and bone geometry at the narrow neck (NN) of the femur was measured three times over 12 months. HSA included cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), and Z-section modulus (Z). Male runners had significantly higher aBMD at TH and WB and greater CSA, CSMI, and Z than male controls at the end of 12 months. Female controls had higher aBMD at the PA spine than female runners at the end of 12 months. Male runners had significant increases in aBMD at the PA (p = 0.003) and lateral spine (p = 0.002), and TH (p = 0.002), female runners had significant decreases in aBMD at TH (p = 0.015) and WB (p = 0.002), male controls had significant increases in aBMD at the PA spine (p

Electromagnetic fields (EMFs) have emerged as a versatile means for osteoporosis treatment and prevention. However, its optimal application parameters are still elusive. Here, we optimized the frequency parameter first by cell culture screening and then by animal experiment validation. Osteoblasts isolated from newborn rats (ROBs) were exposed 90 min/day to 1.8 mT SEMFs at different frequencies (ranging from 10 to 100 Hz, interval of 10 Hz). SEMFs of 1.8 mT inhibited ROB proliferation at 30, 40, 50, 60 Hz, but increased proliferation at 10, 70, 80 Hz. SEMFs of 10, 50, and 70 Hz promoted ROB osteogenic differentiation and mineralization as shown by alkaline phosphatase (ALP) activity, calcium content, and osteogenesis‐related molecule expression analyses, with 50 Hz showing greater effects than 10 and 70 Hz. Treatment of young rats with 1.8 mT SEMFs at 10, 50, or 100 Hz for 2 months significantly increased whole‐body bone mineral density (BMD) and femur microarchitecture, with the 50 Hz group showing the greatest effect. Furthermore, 1.8 mT SEMFs extended primary cilia lengths of ROBs and increased protein kinase A (PKA) activation also in a frequency‐dependent manner, again with 50 Hz SEMFs showing the greatest effect. Pretreatment of ROBs with the PKA inhibitor KT5720 abolished the effects of SEMFs to increase primary cilia length and promote osteogenic differentiation/mineralization. These results indicate that 1.8 mT SEMFs have a frequency window effect in promoting osteogenic differentiation/mineralization in ROBs and bone formation in growing rats, which involve osteoblast primary cilia length extension and PKA activation. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the associations between physical activity level and composite indices of femoral neck strength in a group of young overweight and obese Lebanese men. Eighty overweight and obese (body mass index (BMI) > 25 kg/m2) young men whose ages range between 18 and 35 years participated in this study. Weight and height were measured, and BMI was calculated. Body composition and femoral neck (FN) bone mineral density were measured by dual-energy X-ray absorptiometry (DXA). Compressive strength index (CSI), bending strength index (BSI) and impact strength index (ISI) were calculated. Physical activity level was evaluated by the global physical activity questionnaire (GPAQ). Maximum oxygen consumption (VO 2 max, in L/min) was measured using a valid device. Weight, BMI, fat mass and fat mass percentage were negatively correlated to CSI, BSI and ISI. Physical activity level (h/week) was positively correlated to CSI, BSI and ISI while VO 2 max (mL/min/kg) was positively correlated to CSI and ISI. The positive associations between physical activity and composite indices of femoral neck strength (CSI, BSI and ISI) remained significant after adjustment for body weight. Our study conducted on overweight and obese men shows that physical activity level is a positive determinant of composite indices of femoral neck strength. In overweight men, increasing physical activity level may help to prevent osteoporotic fractures later in life. [ABSTRACT FROM AUTHOR]