Development Of Peak Bone Mass Research Articles

Endocrine Health and Health Care Disparities in the Pediatric and Sexual and Gender Minority Populations: An Endocrine Society Scientific Statement.

Endocrine care of pediatric and adult patients continues to be plagued by health and health care disparities that are perpetuated by the basic structures of our health systems and research modalities, as well as policies that impact access to care and social determinants of health. This scientific statement expands the Society's 2012 statement by focusing on endocrine disease disparities in the pediatric population and sexual and gender minority populations. These include pediatric and adult lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA) persons. The writing group focused on highly prevalent conditions-growth disorders, puberty, metabolic bone disease, type 1 (T1D) and type 2 (T2D) diabetes mellitus, prediabetes, and obesity. Several important findings emerged. Compared with females and non-White children, non-Hispanic White males are more likely to come to medical attention for short stature. Racially and ethnically diverse populations and males are underrepresented in studies of pubertal development and attainment of peak bone mass, with current norms based on European populations. Like adults, racial and ethnic minority youth suffer a higher burden of disease from obesity, T1D and T2D, and have less access to diabetes treatment technologies and bariatric surgery. LGBTQIA youth and adults also face discrimination and multiple barriers to endocrine care due to pathologizing sexual orientation and gender identity, lack of culturally competent care providers, and policies. Multilevel interventions to address these disparities are required. Inclusion of racial, ethnic, and LGBTQIA populations in longitudinal life course studies is needed to assess growth, puberty, and attainment of peak bone mass. Growth and development charts may need to be adapted to non-European populations. In addition, extension of these studies will be required to understand the clinical and physiologic consequences of interventions to address abnormal development in these populations. Health policies should be recrafted to remove barriers in care for children with obesity and/or diabetes and for LGBTQIA children and adults to facilitate comprehensive access to care, therapeutics, and technological advances. Public health interventions encompassing collection of accurate demographic and social needs data, including the intersection of social determinants of health with health outcomes, and enactment of population health level interventions will be essential tools.

Lack of Skeletal Effects in Mice with Targeted Disruptionof Prolyl Hydroxylase Domain 1 (Phd1) Gene Expressed in Chondrocytes.

The critical importance of hypoxia-inducible factor (HIF)s in the regulation of endochondral bone formation is now well established. HIF protein levels are closely regulated by the prolyl hydroxylase domain-containing protein (PHD) mediated ubiquitin-proteasomal degradation pathway. Of the three PHD family members expressed in bone, we previously showed that mice with conditional disruption of the Phd2 gene in chondrocytes led to a massive increase in the trabecular bone mass of the long bones. By contrast, loss of Phd3 expression in chondrocytes had no skeletal effects. To investigate the role of Phd1 expressed in chondrocytes on skeletal development, we conditionally disrupted the Phd1 gene in chondrocytes by crossing Phd1 floxed mice with Collagen 2α1-Cre mice for evaluation of a skeletal phenotype. At 12 weeks of age, neither body weight nor body length was significantly different in the Cre+; Phd1flox/flox conditional knockout (cKO) mice compared to Cre−; Phd1flox/flox wild-type (WT) control mice. Micro-CT measurements revealed significant gender differences in the trabecular bone volume adjusted for tissue volume at the secondary spongiosa of the femur and the tibia for both genotypes, but no genotype differences were found for any of the trabecular bone measurements of either femur or tibia. Similarly, cortical bone parameters were not affected in the Phd1 cKO mice compared to control mice. Histomorphometric analyses revealed no significant differences in bone area, bone formation rate or mineral apposition rate in the secondary spongiosa of femurs between cKO and WT control mice. Loss of Phd1 expression in chondrocytes did not affect the expression of markers of chondrocytes (collage 2, collagen 10) or osteoblasts (alkaline phosphatase, bone sialoprotein) in the bones of cKO mice. Based on these and our published data, we conclude that of the three PHD family members, only Phd2 expressed in chondrocytes regulates endochondral bone formation and development of peak bone mass in mice.

The association of extreme body weight with bone mineral density in Saudi children.

Objective:The objective to investigate the effect of extreme body weight; obesity and undernutrition, on bone mineral density (BMD).Methodology:This study is a descriptive cross-sectional study carried between January and June of 2019, and included 224 children and adolescents without any comorbidities or chronic disease. Important data collected included anthropometrics, past medical and surgical history, history of medication intake, level of physical activity and pubertal assessment. Data entry and analysis were conducted using Statistical Package for Social Sciences version 24.Results:Gender distribution showed 48.2% were male and 51.8% were female. The mean age was 9.98 ± 3.5 years. Mean weight was 34.89 ± 18.2 kg. Mean BMD z-score was − 1.64 ± 1.4. Weight was considered to significantly correlate with BMD stature at a P = 0.014. Subjects who were underweight showed a lower mean BMD z-score of <−2 than those who were overweight/obese (mean BMD z-score = −1.60).Conclusion:Both extremes of weight are considered a significant risk factor for the development of low BMD in children. We recommend the early recognition of weight aberrations and consequent aggressive intervention with strict lifestyle modifications to promote the development of maximum peak bone mass.

Nutritional Supplements and Skeletal Health.

Nutrition influences skeletal health throughout the lifespan, from the impact of maternal intakes during development, through the development of peak bone mass, to the rate of bone loss during aging. However, there are limited data available on the effects of nutritional supplements on bone density, let alone fracture risk. This review will assess the current literature, focusing on human studies, and emphasizing nutrients where bone density or fracture data are available. Calcium and vitamin D supplements, in combination, reduce fracture risk, particularly in populations with low intakes. Extensive recent analyses have supported the safety of these interventions at recommended intakes. There is growing evidence that specific isoflavones may improve bone density although fracture data are lacking. Multiple other nutrient supplements may benefit skeletal health, but data are limited. The effect size of nutrient interventions are relatively small, requiring large sample sizes for trials with bone outcomes, may be difficult to blind, and the impact of supplementation may depend on baseline intake. However, nutrition is the only intervention that can be implemented life long and on a population wide basis. Further investigation is needed into the potential benefits of nutritional supplements to determine in which settings supplements may add benefit in addition to dietary intakes.

Knowledge, Attitude and Practice towards Osteoporosis among General Practitioners Working in Al Majmaah Province, KSA

Background: Osteoporosis is the most common metabolic disorder affecting bone which develops because of normal ageing, excessive bone loss during adulthood and impaired development of peak bone mass. Awareness among physicians is vital for the early detection and timely treatment and hence fractures prevention. The present study was carried out to study the knowledge, attitude and practice towards osteoporosis among general practitioners working in Al Majmaah, KSA. Methodology: This crosssectional research was conducted among all the qualified family physicians, general practitioners and resident doctors in Majmaah province, KSA. Data collection was done based on a standardized KAP questionnaire. Results: All the data were entered and analysed according to the intentions of the present work. Good level of knowledge concerning the diagnosis was observed among the study subjects and a high proportion of respondents believed in the preventive strategies of the disease. Responses were obtained from total of43 practitioners who included 23.3% female, and 76.7% male in and around Majmaah province. Majority (72.1%) of the respondent’s attitude was that osteoporosis has major effect on the health of the community. In relation to practice aspects, prescription of 76.7% responders includes bisphosphonates as the most commonly used drug for treatment of osteoporosis. Conclusion: A considerable level of knowledge and positive attitude towards osteoporosis was found; however, practices for the prevention of osteoporosis still need improvement. There is a need to extend the medical knowledge of general practitioners in Al Majmaah Province, KSA, regarding the contemporary management of osteoporosis and its risk factors. Professional training programs are required to enhance the practitioner’s knowledge and attitude to improve their practices.

Chemokine receptor 3 is a negative regulator of trabecular bone mass in female mice.

Chemokines are secreted by a wide variety of cells; their functions are dependent on the binding to their chemokine receptors (CCRs) which induce directed chemotaxis in nearby responsive cells. Chemokines and their receptors can be induced under several different conditions. Based on data from clinical studies showing an increased expression of chemokine receptor 3 (CCR3) in circulating monocytes of human subjects with lower bone mineral density (BMD) as compared to those with high BMD, we predicted a role for CCR3 in the development of peak bone mass. We, therefore, first evaluated the expression pattern of Ccr3 in bone cells, in comparison to other CCRs, that have common ligands with CCR3. While Ccr1 and Ccr3 messenger RNA (mRNA) levels increased during both RANKL-induced osteoclast differentiation and AA-induced osteoblast differentiation, the levels of Ccr5 mRNA only increased during osteoblast differentiation. To examine if CCR3 influences osteoclast and/or osteoblast differentiation, we evaluated the consequence of blocking CCR3 function using neutralizing antibody on the expression of osteoclast and osteoblast differentiation markers. Treatment with CCR3 neutralizing antibody increased mRNA levels of Trap and cathepsin K in osteoclasts and osteocalcin in osteoblasts compared to cells treated with control IgG. Based on these in vitro findings, we next assessed the role of CCR3 in vivo by evaluating the skeletal phenotypes of Ccr3 knockout and corresponding control littermate mice. Disruption of CCR3 resulted in a significant increase in femur areal BMD at 5 and 8 weeks of age by dual-energy X-ray absorptiometry. Micro-CT analysis revealed a 25% increase in trabecular bone mass at 10 weeks of age caused by corresponding changes in trabecular number and thickness compared to wild type mice. Based on our findings, we conclude that disruption of CCR3 function favors bone mass accumulation, in part via enhancement of bone metabolism. Understanding the molecular pathways through which CCR3 acts to regulate osteoclast and osteoblast functions could lead to new therapeutic approaches to prevent inflammation-induced bone loss.

BONE MINERAL STATUS AND METABOLISM DISORDERS IN PATIENTS WITH CHRONIC SPINAL CORD INJURY

Background. The study of late complications, including osteoporosis, is urgent due to the increasing life expectancy of patients with complete spinal cord injury (SCI). Objective. The aim of the study is to evaluate bone mineral status and bone turnover markers in the patients with chronic SCI.Methods. 73 SCI patients and 57 healthy persons were examined. Bone status was determined by ultrasound (US) densitometry. Bone turnover markers and vitamin D were evaluated by electrochemiluminescence method.Results. In the SCI patients bone mineral status was significantly lower compared with the individuals of control group. The stiffness index (SI) was 51.4±11.8 % vs. 98.5±16.6 %, p&lt;0.05 in men and 50.1±9.8 % vs. 92.9±11.1 %, p&lt;0.05 in women. In the SCI patients the levels of bone turnover markers were significantly higher than the reference values. The bone mineral status of patients with SCI, which occurred before peak bone mass development, is significantly worse, compared with the individuals with the already developed peak bone mass, that makes them a high risk group for fracture. Conclusions. SCI leads to increased bone resorption with development of secondary osteoporosis (according to the ultrasound densitometry of calcaneal bone). In chronic SCI, bone resorption is higher than in the individuals with combined low levels of vitamin D, and the absence of axial load results in continued loss of bone mass.

Pediatric Sports Injury and Bone Health Compliance

Background: Children should be the population of interest in curbing incidence of osteoporosis due to the relationship between peak bone mass development and osteoporosis risk. Patient adherence to medicinal regimens and lifestyle adjustments is of concern to physicians, researchers, and public health officials. This study was designed to evaluate supplementation compliance in children known to be 25(OH) Vitamin D deficient after fracture. Methods: Compliance patterns were …

Associations between socioeconomic factors and proinflammatory cytokines in children, adolescents and young adults: a systematic review protocol

IntroductionThere is now substantial evidence of a social gradient in bone health. Social stressors, related to socioeconomic status, are suggested to produce an inflammatory response marked by increased levels of...

Serum 25-hydroxyvitamin D concentrations and selected diet components in postmenopausal women.

Nutrition and lifestyle factors play an important role in the development and maintenance of peak bone mass and the prevention of bone degradation. The aim of the present study was to assess 25-hydroxy- cholecalciferol [25(OH)D] serum concentration in postmenopausal women during the winter period and the supply of selected components in their diet. The study was conducted on a group of 35 women aged 54&ndash;77, using a question- naire, including a 24-hour recall related to a subject&rsquo;s nutrient consumption. Serum concentrations of 25(OH) D were determined. Body composition was assessed with bioelectrical impedance analysis. Mean 25(OH)D serum concentration was found to be 61.2% of the minimum healthy level, according to the reference values. The supply of vitamin D and calcium covered 36.2% and 56.7% of RDA respectively. Correlation analysis has shown a significant inverse relationship between 25(OH)D serum con- centration and body fat (p < 0.05). The study indicates a decreased serum concentration of 25(OH)D in postmenopausal women during the winter period and a low supply of vitamin D and calcium in their diet. Nutrition education should be introduced to the adult population to prevent bone fractures.

A randomized, controlled trial evaluating the efficacy of an online intervention targeting vitamin D intake, knowledge and status among young adults.

BackgroundVitamin D plays a key role in bone health. Consuming adequate vitamin D during young adulthood is important due to the development of peak bone mass; however, many Canadian young adults do not meet vitamin D recommendations. This study aimed to improve knowledge, perceptions, dietary intake and blood concentrations of vitamin D among a sample of young adults.MethodsUsing a pre-post design, 90 Ontario adults (38 men, 52 women; 18–25 years), were randomly assigned to intervention or control groups. Participants completed a socio-demographic survey, pre-post food frequency questionnaire, and a vitamin D knowledge questionnaire (3 time-points). The intervention group watched a video, received online information and tracked intake of vitamin D using a mobile application for 12 weeks. A sub-sample of participants completed pre-post blood 25(OH)D3 tests. Univariate ANOVA tested pre-post between-group differences in vitamin D intake and status. Repeated-measures ANOVA tested between-group differences in vitamin D knowledge and perceptions across 3 time-points.ResultsMean vitamin D intake in the sample increased significantly from pre-test (M = 407, SD = 460 IU) to post-test (M = 619, SD = 655 IU), t(88) = 5.37, p < 0.001. Mean intake increased significantly more in the intervention than control group after controlling for gender and education, F(1, 85) = 4.09, p = 0.046. Mean blood vitamin D3 was significantly higher among non-Caucasian than Caucasian participants at baseline, t(56.7) = 3.49, p = 0.001. Mean blood vitamin D3 increased significantly from pre-test (M = 28, SD = 16 nmol/L) to post-test (M = 43, SD = 29 nmol/L), t(53) = 11.36, p < 0.001, but did not differ significantly between groups. The increase in vitamin D knowledge from time 1–3 was significantly higher in the intervention than control group (t(88) = 2.26, p = 0.03). The intervention group (M = 3.52, SE = 0.13) had higher overall perceived importance of vitamin D supplementation than the control (M = 3.16, SE = 0.12), F(1, 88) = 4.38, p = 0.04, ηp 2 = 0.05.ConclusionsAlthough recommendations suggest blood 25(OH)D3 concentrations of ≥50-75 nmol/L, vitamin D status was below national recommendations. While participating in an intervention did not improve vitamin D status, it led to increased vitamin D intake, knowledge and perceived importance of supplementation.Trial registrationClinicalTrails.gov registration #: NCT02118129.Electronic supplementary materialThe online version of this article (doi:10.1186/s12966-016-0443-1) contains supplementary material, which is available to authorized users.

The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations.

Lifestyle choices influence 20–40 % of adult peak bone mass. Therefore, optimization of lifestyle factors known to influence peak bone mass and strength is an important strategy aimed at reducing risk of osteoporosis or low bone mass later in life. The National Osteoporosis Foundation has issued this scientific statement to provide evidence-based guidance and a national implementation strategy for the purpose of helping individuals achieve maximal peak bone mass early in life. In this scientific statement, we (1) report the results of an evidence-based review of the literature since 2000 on factors that influence achieving the full genetic potential for skeletal mass; (2) recommend lifestyle choices that promote maximal bone health throughout the lifespan; (3) outline a research agenda to address current gaps; and (4) identify implementation strategies. We conducted a systematic review of the role of individual nutrients, food patterns, special issues, contraceptives, and physical activity on bone mass and strength development in youth. An evidence grading system was applied to describe the strength of available evidence on these individual modifiable lifestyle factors that may (or may not) influence the development of peak bone mass (Table 1). A summary of the grades for each of these factors is given below. We describe the underpinning biology of these relationships as well as other factors for which a systematic review approach was not possible. Articles published since 2000, all of which followed the report by Heaney et al. [1] published in that year, were considered for this scientific statement. This current review is a systematic update of the previous review conducted by the National Osteoporosis Foundation [1].Lifestyle FactorGrade Macronutrients FatD ProteinC Micronutrients CalciumA Vitamin DB Micronutrients other than calcium and vitamin DD Food Patterns DairyB FiberC Fruits and vegetablesC Detriment of cola and caffeinated beveragesC Infant Nutrition Duration of breastfeedingD Breastfeeding versus formula feedingD Enriched formula feedingD Adolescent Special Issues Detriment of oral contraceptivesD Detriment of DMPA injectionsB Detriment of alcoholD Detriment of smokingC Physical Activity and Exercise Effect on bone mass and densityA Effect on bone structural outcomesB Considering the evidence-based literature review, we recommend lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline a research agenda to address current gaps in knowledge. The best evidence (grade A) is available for positive effects of calcium intake and physical activity, especially during the late childhood and peripubertal years—a critical period for bone accretion. Good evidence is also available for a role of vitamin D and dairy consumption and a detriment of DMPA injections. However, more rigorous trial data on many other lifestyle choices are needed and this need is outlined in our research agenda. Implementation strategies for lifestyle modifications to promote development of peak bone mass and strength within one’s genetic potential require a multisectored (i.e., family, schools, healthcare systems) approach.

Vitamin D and bone health

Throughout the life-cycle, the skeleton requires optimum development and maintenance of its integrity to prevent fracture. Bones break because the loads placed upon them exceed the ability of the bone to absorb the energy involved. It is now estimated that 1:3 women and 1:12 men over the age of 55 years will suffer from osteoporosis in their lifetime and in the UK, at a cost in excess of £1.7 billion per annum to the exchequer. The pathogenesis of osteoporosis is multi-factorial. Both the development of peak bone mass and the rate of bone loss are determined by key endogenous and exogenous factors. Calcium supplements appear to be effective in reducing bone loss in late menopausal women (>5 years post-menopause), particularly in those with low habitual calcium intake (< 400mg/d). In younger postmenopausal women, who are not vitamin D deficient, vitamin D supplementation has little effect on BMD. However, vitamin D and calcium supplementation studies have been shown to reduce fracture rates in the institutionalized elderly but there remains controversy as to whether supplementation is effective in reducing fracture in free-living populations. Re-defining vitamin D requirements in the UK is urgently needed since there is evidence of extensive hypovitaminosis D in the UK. Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention. The role of other micronutrients on bone remains to be fully defined, although there are promising data in the literature for a clear link between vitamin K nutrition, dietary protein and dietary alkali on skeletal integrity including fracture reduction.

HIV and bone mineral density.

Bone mineral density (BMD) loss is a phenomenon considered to be physiologic in elderly adults. However, certain categories of patients may be at higher (e.g., post-menopausal women) or earlier (e.g., patients with chronic viral infections such as HBV or HIV) risk of BMD loss. Current guidelines recommend an evaluation of bone mineral density (BMD) through dual X-ray absorptiometry (DXA scan) in the general population for women ≥65 years of age, for men ≥70 years of age, for persons of any age with history of a fragility fracture, or for any patient with suspected bone impairment. As peak bone mass development takes place during late childhood, adolescence and early adulthood (Mora S, Gilsanz V. Endocrinol Metab Clin North Am 2003;32:39–63), bone impairment may represent an important issue for the specific Romanian cohort of HIV-positive patients, “yesterday's children, today's young adults”, as they received antiretroviral treatment (ART) early on in childhood, during the period of bone development. Given the fact that osteoporosis is mainly asymptomatic prior to the first bone fracture, there is an imperative need to cross-sectionally determine BMD and to longitudinally evaluate the trend and pace of BMD loss in the Romanian cohort, in order to determine the right timing for any interventions deemed necessary to slow down the progression of bone impairment or to prevent future complications such as fragility fractures. The effect of the viral infection per se and/or that of ART exposure on bone mineralization represent critical areas for research. In 2014 we initiated a national survey for osteo-renal impairment in the Romanian HIV cohort, designed to screen and monitor a total of 1000 patients from all over the country to determine, among other factors, their real level of BMD, using a DXA scan for a much younger population than that targeted by current guidelines. The study also aims to underline variation in the patterns and dynamics of skeletal growth, as currently available bone mass measurements for youth, and normative databases appear to be insufficient (Lewiecki EM, et al. Bone. 2008;43:1115–21; Webber CE, et al. Osteoporos Int. 2009;20:113–21). Scanning for bone and renal impairment is essential if we target a healthy life during this long journey for our young HIV-infected patients, particularly as the mean age for the Romanian HIV cohort in 2014 is 24 years. After identifying the status of the population we can start designing and implementing specific guidelines and recommendations for risk factors and general health management, including exercise, nutrition, and lifestyle changes.

Increased physical activity is associated with enhanced development of peak bone mass in men: A five-year longitudinal study

Data supporting physical activity guidelines to optimize bone development in men is sparse. Peak bone mass is believed to be important for the risk of osteoporosis later in life. The objective of this study was to determine if an increased amount of physical activity over a 5-year period was associated with increased bone mineral content (BMC), areal (aBMD) and volumetric (vBMD) bone mineral density, and a favorable development of cortical bone size in young adult men. The original 1068 young men, initially enrolled in the Gothenburg Osteoporosis and Obesity Determinants (GOOD) study, were invited to participate in the longitudinal study, and a total of 833 men (78%), 24.1 ± 0.6 years of age, were included in the 5-year follow-up. A standardized self-administered questionnaire was used to collect information about patterns of physical activity at both the baseline and 5-year follow-up visits. BMC and aBMD were measured using dual energy X-ray absorptiometry, whereas vBMD and bone geometry were measured by peripheral quantitative computed tomography. Increased physical activity between the baseline and follow-up visits was associated with a favorable development in BMC of the total body, and aBMD of the lumbar spine and total hip (p < 0.001), as well as with development of a larger cortex (cortical cross sectional area), and a denser trabecular bone of the tibia (p < 0.001). In conclusion, increased physical activity was related to an advantageous development of aBMD, trabecular vBMD and cortical bone size, indicating that exercise is important in optimizing peak bone mass in young men. © 2012 American Society for Bone and Mineral Research.

Cortical Consolidation due to Increased Mineralization and Endosteal Contraction in Young Adult Men: A Five-Year Longitudinal Study

Peak bone mass is an important factor in the lifetime risk of developing osteoporosis. Large, longitudinal studies investigating the age of attainment of site-specific peak bone mass are lacking. OBJECTIVE AND MAIN OUTCOME MEASURES: The main outcome measures were to determine the site-specific development of peak bone mass in appendicular and axial skeletal sites and in the trabecular and cortical bone compartments, using both dual x-ray absorptiometry and peripheral computed tomography. In total, 833 men [aged 24.1 ± 0.6 yr (mean ± sd)] from the original population-based Gothenburg Osteoporosis and Obesity Determinants Study (n = 1068) were included in this follow-up examination at 61.2 ± 2.3 months. Areal bone mineral density (aBMD) was measured with dual x-ray absorptiometry, whereas cortical and trabecular volumetric bone mineral density and bone size were measured by peripheral computed tomography at baseline and at the 5-yr follow-up. During the 5-yr study period, aBMD of the total body, lumbar spine, and radius increased by 3.4, 4.2, and 7.8%, respectively, whereas a decrease in aBMD of the total hip of 1.9% was observed (P < 0.0001). Increments of 2.1 and 0.7% were seen for cortical volumetric bone mineral density of the radius and tibia, respectively (P < 0.0001), whereas cortical thickness increased by 3.8% at the radius and 6.5% at the tibia due to diminished endosteal circumference (radius 2.3% and tibia 4.6%, P < 0.0001). aBMD decreased at the hip but increased at the spine and radius, in which the increment was explained by continued mineralization and augmented cortical thickness due to endosteal contraction in men between ages 19 and 24 yr.

Increased physical activity is associated with optimized development of peak bone mass mainly due to augmented cortical bone size in men: A five year longitudinal study

Increased physical activity is associated with optimized development of peak bone mass mainly due to augmented cortical bone size in men: A five year longitudinal study

Altered Antioxidant and Trace-Element Status in Adolescent Female Gymnasts

Physical activity is associated with the generation of reactive oxygen species and may lead to decreased levels of plasma antioxidants and increased oxidant stress. Some studies have reported that antioxidant supplements can reduce the consequences of oxidative stress during exercise. In this study the authors aimed to assess the chronic effects of exercise on endogenous serum antioxidant enzyme concentrations. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were measured in adolescent girls who were either competitive gymnasts or sedentary controls. The relationship between age, body-mass index, dietary intake, trace-element status, and serum GPx and SOD was determined. The participants in the study were part of a 3-yr longitudinal investigation of exercise and peak bone-mass development in 38 competitive gymnasts and 40 healthy sedentary adolescent females 8-17 yr of age. Serum GPx and SOD were measured using colorimetric assays, and trace elements were measured using inductively coupled plasma mass spectrometry. The mean serum GPx concentrations were significantly higher in the gymnasts than in the sedentary females (157 ± 11.1 vs. 126 ± 8.8 U/ml, p < .05). In contrast, serum SOD concentrations were significantly lower in the gymnasts than in the sedentary group (7.24 ± 2.6 vs. 8.57 ± 2.3 U/ml, p < .05). Serum selenium, zinc, and copper were higher in the physically active group than in the inactive group (0.89 ± 0.03, 10.86 ± 0.39, 14.50 ± 0.50 vs. 0.81 ± 0.03, 10.32 ± 0.28, and 14.38 ± 0.42 µmol/L, respectively), although only serum selenium reached statistical significance (p < .05). The findings show that young female gymnasts have an altered antioxidant enzyme profile compared with their less physically active peers.

Predicting Bone Mass in College Aged Female Gymnasts

Achieving peak bone mass in a female's life is imperative to avoid osteoporotic fractures. According to the National Osteoporosis Foundation, about 85-90% of a females bone mass will be developed by the age of 18. There are several lifestyle and behavioral characteristics that are well documented to be detrimental to peak bone mass development including excessive alcohol consumption and smoking. Less documented are the activities, such as motor activity, that have positive effects on bone mineral density. PURPOSE: The purpose of this study is to see if body weight and muscular strength are valid predictors of bone mineral density in college aged female gymnasts. METHODS: Ten female athletes participated in the study with mean (± SD) age and body weight at 20.15 ± 1.49 yr. and 131.39 ± 14 pounds. All athletes were tested on two days. Day one consisted of bone density scans with height and weight measures taken prior to the scan. Day two consisted of a vertical power test, isokinetic leg strength, and horizontal power test. RESULTS: A multiple regression analysis was used with isokinetic strength of the dominant leg at 60°/second and body weight as the predictor variables regressing on the criterion variable, bone mineral density. Statistical significance was set at a =.05. The output was analyzed for influential data points using leverage (hi >.60) and Cook's D to determine if there were any misleading data. Leverage and Cook's D both indicated that there were not influential outliers in the data. Results indicated that significant differences existed; F (2, 9) = 5.45, p <.05 and that the predictors accounted for over half of the variance in bone mineral density (R2 =.61). Follow up analysis indicated that neither muscle strength, F (1, 9) = 4.86, p =.06, or body weight, F (1, 9) =.50, p =.50 were individually significant. The semi-partial squared correlations revealed that isokinetic strength accounted for 27% of the variance, (b =.64, p =.06), whereas body weight accounted for 3%, (b =.21, p =.50). CONCLUSION: Muscle strength and body weight are predictors of bone mineral density in college aged female gymnasts, with muscular strength accounting for more of the variance.

Maternal high-fat diet: effects on offspring bone structure

Peak bone mass is believed to partly be programmed in utero. Mouse dams and offspring were given a high-fat diet and offspring studied as adults. Female offspring from high-fat dams exhibited altered trabecular structure indicative of in utero programming. In utero nutrition has consequences in later life. Epidemiological studies suggest that skeletal growth is programmed during intrauterine and early postnatal life. We hypothesise that development of optimal peak bone mass has, in part, a foetal origin and investigated this using a mouse model of maternal dietary fat excess. Offspring from mouse dams fed either standard chow (C) or lifetime high-fat diet (HF) were maintained on a HF diet to adulthood. Femur samples were taken at 30 weeks of age and bone structure, adiposity and strength analysed. Sample sizes were four to six for each sex and each diet group. Offspring from HF-fed dams showed increased adiposity in the femur in comparison to offspring from C-fed dams. Female offspring from HF dams exhibited altered trabecular structure indicative of in utero programming. A maternal HF diet during pregnancy increases bone marrow adiposity and alters bone structure in their offspring.