The Determinants of Peak Bone Mass

Cross-sectional and longitudinal associations between physical activity, sedentary behaviour and bone stiffness index across weight status in European children and adolescents

Background

The associations between physical activity (PA), sedentary behaviour (SB) and bone health may be differentially affected by weight status during growth. This study aims to assess the cross-sectional and longitudinal associations between PA, SB and bone stiffness index (SI) in European children and adolescents, taking the weight status into consideration.

Methods

Calcaneus SI was first measured by quantitative ultrasound among children aged 2–9 years old in 2007/08. It was measured again after 2 years in the IDEFICS study and after 6 years in the I. Family study. A sample of 2008 participants with time spent at sports clubs, watching TV and playing computer/games self-reported by questionnaire, and a subsample of 1037 participants with SB, light PA (LPA) and moderate-to-vigorous PA (MVPA) objectively measured using Actigraph accelerometers were included in the analyses. Weight status was defined as thin/normal and overweight/obese according to the extended International Obesity Task Force criteria. Linear mixed-effects models were used to estimate the cross-sectional and longitudinal associations between PA, SB and SI percentiles, stratified by weight status.

Results

The cross-sectional association between weekly duration of watching TV and SI percentiles was negative in thin/normal weight group (β = − 0.35, p = 0.008). However, baseline weekly duration of watching TV (β = − 0.63, p = 0.021) and change after 2 years (β = − 0.63, p = 0.022) as well as the change in weekly duration of playing computer/games after 6 years (β = − 0.75, p = 0.019) were inversely associated with corresponding changes in SI percentiles in overweight/obese group. Change in time spent at sports clubs was positively associated with change in SI percentiles after 2 years (β = 1.28, p = 0.001), with comparable effect sizes across weight status. In the subsample with accelerometer data, we found a positive cross-sectional association between MVPA and SI percentiles in thin/normal weight group. Baseline MVPA predicted changes in SI percentiles after 2 and 6 years in all groups.

Conclusions

Our results suggested the beneficial effect of PA on SI. However, the increasing durations of screen-based SB might be risk factors for SI development, especially in overweight/obese children and adolescents.

Age- and Strain-Related Differences in Bone Microstructure and Body Composition During Development in Inbred Male Mouse Strains

We explored age- and strain-related differences in bone microstructure and body composition in male C57BL/6J, DBA/2JRj and C3H/J mice. Bone microstructure of the femur, tibia and L4 was assessed by μCT at the age of 8, 16 and 24 weeks. The weight of several muscles and fat depots were measured at the same time points. At all timepoints, C3H/J mice had the thickest cortices followed by DBA/2JRj and C57BL/6J mice. Nevertheless, C57BL/6J mice had higher Tb.BV/TV and Tb.N, and lower Tb.Sp than DBA/2JRj and C3H/J mice at least at 24 weeks of age. Skeletal development patterns differed among strains. C57BL/6J and DBA/2JRj mice, but not C3H/J mice, experienced significant increases in the sum of the masses of 6 individual muscles by 24 weeks of age. In C57BL/6J and DBA/2JRj mice, the mass of selected fat depots reached highest values at 24 weeks, whist, in C3H/J mice, the highest values of fat depots masses were achieved at 16 weeks. Early strain differences in muscle and fat masses were largely diminished by 24 weeks of age. C3H/J and C57BL/6J mice displayed the most favorable cortical and trabecular bone parameters, respectively. Strain differences in body composition were less overt than strain specificity in bone microstructure, however, they possibly influenced aspects of skeletal development.

Influence of badminton practice on calcaneal bone stiffness and plantar pressure

Objectives: The aim of this study was to analyze the plantar pressures and bone stiffness of the calcaneus in badminton players compare to healthy participants, as well as to detect possible asymmetries and chronic adaptations derived from the prolonged practice of badminton.Methods: Twenty-two badminton players (35.2 ± 13.6 years, 169.4 ± 8.2 cm, 67.6 ± 13.7 kg) and 30 healthy controls (32.2 ± 12.8 years, 170.7 ± 9.5 cm, 66.25 ± 14.84 kg) volunteered to participate in this investigation. A Footwork® Pro pressure platform was used to study plantar pressures and an Achilles® bone scanner was used to record the bone stiffness of the calcaneus. The variables analyzed were plantar surface, percentage of force per area (forefoot and hindfoot), distance between the center of pressure and the projection of the center of mass in standing, and calcaneal bone stiffness.Results: The values of bone stiffness of the calcaneus were higher in badminton players than control group in the dominant lower limb (Badminton = 114.32 ± 18.97 U.A. vs. Control = 102.07 ± 16.36 U.A.; p = 0.019) and non-dominant lower limb (Badminton = 115.12 ± 21.95 U.A. vs Control = 101.37 ± 15.72 U.A.; p = 0.014). Badminton players showed asymmetric values in mean pressure (dominant = 35.41 ± 6.05 Kpa vs. non-dominant = 39.21 ± 6.54 Kpa; p = 0.011) and distance among center of pressure of each foot and center of mass (dominant = 11.28 ± 1.65 cm vs. non-dominant = 10.48 ± 1.63 cm; p = 0.025).Conclusions: The calcaneal stiffness of the badminton players was higher than control group, which places badminton in the category of osteogenic sports. The badminton players showed an asymmetric pattern during the static balance, which may be an indicative of asymmetries derived from the continued practice of badminton.

Hormonal Contraception and Bone Health in Adolescents

Hormonal contraception is prescribed commonly to adolescents for myriad indications from pregnancy prevention to treatment for acne, hirsutism or dysmenorrhea. Although use of these hormones generally has no effect or benefits bone health in mature premenopausal women, the same may not be true for adolescents. The teen years are a critical period for acquiring peak bone strength. Sex hormones, growth hormone, and insulin-like growth factors (IGFs) interact to modulate the changes in bone size, geometry, mineral content, and microarchitecture that determine skeletal strength. Combined oral contraceptives (COCs) and intramuscular depo medroxyprogesterone (DMPA) can compromise the expected gains in adolescence by altering estrogen and IGF concentrations. Use of these medications has been associated with slower accrual of bone mineral density (BMD) and increased fracture risk in some studies. Far less is known about the skeletal effects of the newer long acting reversible contraceptives (LARCs). This review takes a critical look at the gaps in current knowledge of the skeletal effects of COCs, DMPA, and LARCs and underscores the need for additional research.

Cinnamon-flavored electronic cigarette liquids and aerosols induce oxidative stress in human osteoblast-like MG-63 cells

As noncombustible nicotine delivery devices, electronic cigarettes (e-cigarettes) are the most popular tobacco product among youth. The widespread popularity of e-cigarettes combined with possible health consequences suggest a need to further research health hazards associated with e-cigarette use. Since conventional tobacco use is a risk factor for osteoporosis, this study investigates the impact of nicotine-free, cinnamon-flavored e-cigarette liquid (e-liquid) on bone-forming osteoblasts compared to flavorless e-liquid. Human tumor-derived osteoblast-like MG-63 cells were exposed for 24 h or 48 h to 0.0.4 %, 0.04 %, 0.4 % or 1 % of unvaped e-liquid or 0.0025 %, 0.025 %, 0.25 %, 1 % or 2.5 % of aerosol condensate in addition to a culture medium only control. Changes in cell viability were assessed by MTT assay, and the expression of a key bone protein, collagen type I, was analyzed by immunofluorescence. Production of reactive oxygen species (ROS) was detected by fluorometry to assess oxidative stress. Cell viability decreased in a dose-dependent manner, and ROS production increased, which was most pronounced with cinnamon-flavored e-liquids. There were no detectable changes in collagen type I protein following exposure to any of the aerosol condensates. This study demonstrates osteoblast-like cells are sensitive to both e-liquids and aerosol condensates and suggests the cytotoxicity of cinnamon-flavored e-liquids might be associated with oxidative stress rather than changes in collagen type I protein expression. This in vitro study provides insight into the potential impacts of e-cigarette use on bone cells.

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.

Impact of Estimated Pre-Exposure Prophylaxis (PrEP) Adherence Patterns on Bone Mineral Density in a Large PrEP Demonstration Project

Bone mineral density (BMD) declines due to tenofovir-containing pre-exposure prophylaxis (PrEP) have varied among PrEP demonstration projects, potentially related to variable adherence. Characterization of BMD changes in highly adherent individuals, estimated via tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS), can assist clinicians when counseling patients. Cisgender men who have sex with men and transwomen in the optional dual-energy X-ray absorptiometry (DXA) substudy of a large, international, open-label PrEP demonstration project, the iPrEx-open-label extension (OLE) study underwent DXA scans and DBS collection every 24 weeks, with average weekly dosing adherence patterns (2, 4, and 7 doses/week) estimated from validated TFV-DP cut-offs. The mean percent BMD change was estimated in strata of average weekly adherence by using a linear mixed-effects model to calculate the BMD decline in highly adherent individuals on PrEP for the first time. DXA/DBS data were available for 254 individuals over a median of 24 weeks in iPrEx-OLE from June 2011 to December 2013. The percent decline in spine BMD was monotonically associated with strata of increasing average weekly adherence (p < .001 trend); the p value for trends using hip BMD measurements was .07. Individuals with estimated daily adherence experienced a 1.2% decrease in spine BMD and a 0.5% drop in hip BMD. In highly adherent PrEP users, we found a lower-than-expected drop in BMD when compared with previous studies. This drop is likely not clinically significant for most PrEP users. However, for those at the highest risk of fracture who plan prolonged PrEP use, alternate PrEP strategies could be considered.

Per- and Polyfluoroalkyl Substance Plasma Concentrations and Bone Mineral Density in Midchildhood: A Cross-Sectional Study (Project Viva, United States)

BACKGROUND

Identifying factors that impair bone accrual during childhood is a critical step toward osteoporosis prevention. Exposure to per- and polyfluoroalkyl substances (PFASs) has been associated with lower bone mineral density, but data are limited, particularly in children.

METHODS

We studied 576 children in Project Viva, a Boston-area cohort of mother/child pairs recruited prenatally from 1999 to 2002. We quantified plasma concentrations of several PFASs and measured areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) in midchildhood. We used linear regression to examine associations between plasma concentrations of individual PFASs and aBMD z-score. We used weighted quantile sum (WQS) regression to examine the association of the PFAS mixture with aBMD z-score. All models were adjusted for maternal age, education, annual household income, census tract median household income, and child age, sex, race/ethnicity, dairy intake, physical activity, and year of blood draw.

RESULTS

Children were [[Formula: see text]] [Formula: see text] of age. The highest PFAS plasma concentrations were of perfluorooctanesulfonic acid (PFOS) {median [interquartile range (IQR)]: 6.4 (5.6) ng/mL} and perfluorooctanoic acid (PFOA) [median (IQR): 4.4 (3.2) ng/mL]. Using linear regression, children with higher plasma concentrations of PFOA, PFOS, and perfluorodecanoate (PFDA) had lower aBMD z-scores [e.g., [Formula: see text]: [Formula: see text]; 95% confidence interval (CI): [Formula: see text], [Formula: see text] per doubling of PFOA]. The PFAS mixture was negatively associated with aBMD z-score ([Formula: see text]: [Formula: see text]; 95% CI: [Formula: see text], [Formula: see text] per IQR increment of the mixture index).

CONCLUSIONS

PFAS exposure may impair bone accrual in childhood and peak bone mass, an important determinant of lifelong skeletal health. https://doi.org/10.1289/EHP4918.

Dietary inflammatory index® and cortical bone outcomes in healthy adolescent children

Diet is thought to modulate inflammation. This study shows no relationships between the dietary inflammatory index (DII) and biomarkers of inflammation or bone after adjusting for covariates. Monocyte chemoattractant protein-1 was inversely associated with peripheral tibia cortical thickness and prospective childhood studies should be conducted to better understand this relationship and to determine if there are long-term consequences in adulthood.

INTRODUCTION

Examine the relationships between the DII-scores and bone and biomarkers of inflammation in 290 adolescents, ages 9-13 years.

METHODS

DII-scores were calculated from 3-day diet records and categorized into tertiles, low (< - 1.34), medium (- 1.34 to 1.41), and high (> 1.41) inflammation. Radius and tibia bone were assessed via peripheral quantitative computed tomography (Stratec XCT 2000) at the 66% site relative to the distal growth plate. Fasting serum was measured for tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1). The relationships between DII-scores and bone and biomarkers of inflammation were assessed using bivariate and partial correlations adjusting for sexual maturation, sex, race, muscle cross-sectional area, and height. ANOVA/ANCOVA models were used to compare DII-tertiles with dependent variables.

RESULTS

DII-scores were negatively associated with tibia trabecular area (TtAr; r = - .141, P = .019), periosteal perimeter (PsPM; r = - .145, P = .016), endosteal perimeter (r = - .145, P = .016), strength strain index (SSI; r = - .129, P = .032), and radius TtAr (r = - .140, P = .020), PsPM (r = -.138, P = .027) and SSI (r = -.131, P = .036) but nullified when adjusting for covariates. Tibia PsPM was higher in the low DII group compared to the medium (P = .050) and high (P = .046) groups but nullified after controlling for covariates. DII-scores were not associated with TNF-α, VEGF, or IL-6, but were associated with MCP-1 only in the unadjusted model (r = .125, P = .042). In the adjusted model, MCP-1 was inversely associated with tibia cortical thickness (r = -.150 P = .030).

CONCLUSION

The DII-scores were not related to biomarkers of inflammation or bone; however, the biomarker of inflammation, MCP-1 was negatively associated with tibia CtTh. Future prospective pediatric studies should be conducted to better understand this relationship and determine if there are long-term implications in adulthood.

Risk factors for premature aging in childhood cancer survivors

Over the last decades, the overall survival rate for childhood cancer has increased from 20% to 80%, which is the result of advances in treatment. Nevertheless, most data from the international registers of childhood cancer survivors (CCS) stress that this population of patients is at high risk for late sequelae and their biological aging starts earlier in life. Anticancer therapy (chemotherapy, radiotherapy, surgery, immunotherapy) affects the intracellular processes leading to the chronic deterioration of organ function and premature senescence. The present review focuses on the late effects of anticancer treatment on various human organs that may lead to premature aging.

Developmental factors associated with decline in grip strength from midlife to old age: a British birth cohort study

OBJECTIVES

To test whether developmental factors are associated with grip strength trajectories between 53 and 69 years, and operate independently or on the same pathway/s as adult factors.

DESIGN

British birth cohort study.

SETTING

England, Scotland and Wales.

PARTICIPANTS

3058 men and women.

MAIN OUTCOME MEASURES

Grip strength (kg) at ages 53, 60-64 and 69 were analysed using multilevel models to estimate associations with developmental factors (birth weight, growth parameters, motor and cognitive development) and father's social class, and investigate adult factors that could explain observed associations, testing for age and sex interactions.

RESULTS

In men, heavier birth weight, beginning to walk 'on time', later puberty and greater weight 0-26 years and in women, heavier birth weight and earlier age at first standing were independently associated with stronger grip but not with its decline. The slower decline in grip strength (by 0.07 kg/year, 95% CI 0.02 to 0.11 per 1 SD, p=0.003) in men of higher cognitive ability was attenuated by adjusting for adult verbal memory.

CONCLUSIONS

Patterns of growth and motor development have persisting associations with grip strength between midlife and old age. The strengthening associations with cognition suggest that, at older ages, grip strength increasingly reflects neural ageing processes. Interventions across life that promote muscle development or maintain muscle strength should increase the chance of an independent old age.

Effects of Parity and Breastfeeding Duration on Bone Density in Postmenopausal Women

PURPOSE

This study aimed to identify the effect of parity and breastfeeding duration and the occurrence of lumbar vertebral and femoral neck osteoporosis in Korean postmenopausal women.

METHODS

This study analyzed the data of 1,770 women based on the 2010-2011 results of the Korea National Health and Nutrition Examination Survey. Extracted data concerning bone density included variables known to be associated with osteoporosis. Complex sample multivariate logistic regression analysis was conducted to determine whether parity and breastfeeding duration were associated with osteoporosis in postmenopausal women.

RESULTS

Parity was not associated with postmenopausal osteoporosis in the femoral neck or lumbar vertebrae; however, the risk of femoral neck osteopenia was significantly higher in women with a history of 12-24 months of breastfeeding than in women who breastfed for less than 12 months (odds ratio = 2.12, 95% confidence interval = 1.07-4.21). In women who breastfed for 24 months or longer, the risk of lumbar vertebral osteoporosis was significantly higher than in those who breastfed for less than 12 months (odds ratio = 2.73, 95% confidence interval = 1.18-6.32).

CONCLUSION

Breastfeeding duration may affect the occurrence of lumbar vertebral or femoral neck osteopenia or osteoporosis. Therefore, women who breastfeed for one year or more require education on the risk of bone loss and the need for preventive measures such as adequate calcium intake and physical exercise.

The Role of Tocotrienol in Preventing Male Osteoporosis-A Review of Current Evidence

Male osteoporosis is a significant but undetermined healthcare problem. Men suffer from a higher mortality rate post-fracture than women and they are marginalized in osteoporosis treatment. The current prophylactic agents for osteoporosis are limited. Functional food components such as tocotrienol may be an alternative option for osteoporosis prevention in men. This paper aims to review the current evidence regarding the skeletal effects of tocotrienol in animal models of male osteoporosis and its potential antiosteoporotic mechanism. The efficacy of tocotrienol of various sources (single isoform, palm and annatto vitamin E mixture) had been tested in animal models of bone loss induced by testosterone deficiency (orchidectomy and buserelin), metabolic syndrome, nicotine, alcoholism, and glucocorticoid. The treated animals showed improvements ranging from bone microstructural indices, histomorphometric indices, calcium content, and mechanical strength. The bone-sparing effects of tocotrienol may be exerted through its antioxidant, anti-inflammatory, and mevalonate-suppressive pathways. However, information pertaining to its mechanism of actions is superficial and warrants further studies. As a conclusion, tocotrienol could serve as a functional food component to prevent male osteoporosis, but its application requires validation from a clinical trial in men.

Zoledronic Acid Modulation of TRPV1 Channel Currents in Osteoblast Cell Line and Native Rat and Mouse Bone Marrow-Derived Osteoblasts: Cell Proliferation and Mineralization Effect

Bisphosphonates (BPs) reduce bone pain and fractures by balancing the osteoblast/osteoclast ratio. The behavior of ion channels in the presence of BPs is not known. To investigate this, the effect of zoledronic acid BP (ZOL) (3 × 10⁻⁸ to 5 × 10⁻⁴ M) treatment, on ion channels, cell proliferation, and mineralization, has been investigated on preosteoclast-like cells, RAW264.7, preosteoblast-like cells MC3T3-E1, and rat/mouse native bone marrow-derived osteoblasts. In whole-cell patch clamp on cell line- and bone marrow-derived osteoblasts, ZOL potentiated outward currents. On RAW264.7, ZOL (10⁻⁴ M)-evoked current was reduced by the Kv channel blocker tetraethylammonium hydrochloride (TEA), but not by the selective TRPV1-channel antagonist capsazepine. On MC3T3-E1 cells and bone marrow-derived osteoblasts, ZOL-evoked current (5 × 10⁻⁸ to 10⁻⁴ M) was reduced by capsazepine, whereas the selective TRPV1-channel agonist capsaicin potentiated the control current. In the cell proliferation assay, 72 h incubation of RAW264.7 and MC3T3-E1 cells with ZOL reduced proliferation, with IC₅₀ values of 2.62 × 10⁻⁷ M and 2.02 × 10⁻⁵ M, respectively. Mineralization of MC3T3-E1 cells and bone marrow-derived osteoblasts was observed in the presence of capsaicin and ZOL (5 × 10⁻⁸–10⁻⁷ M); ZOL effects were antagonized by capsazepine. In summary, the ZOL-induced activation of TRPV1 channel mediates the mineralization of osteoblasts and counterbalances the antiproliferative effects, increasing the IC₅₀. This mechanism is not operative in osteoclasts lacking the TRPV1 channel.

Atrophic Gastritis as a Risk Factor for Bone Loss in Premenopausal Women in Their 40s: A Retrospective Cohort Study

This study assessed the effects of atrophic gastritis on bone mineral density (BMD) in premenopausal women in their 40s. We performed a retrospective analysis of medical records of premenopausal women in their 40s who underwent a health checkup, esophagogastroduodenoscopy, and bone densitometry at least thrice, 24 months apart, between January 2006 and December 2016. Based on first-visit esophagogastroduodenoscopy results, patients were divided into atrophic and non-atrophic gastritis groups; BMD changes over time were analyzed. Patients were further divided into subgroups depending on atrophic gastritis persistence; differences and absolute changes in BMD were assessed. BMD in both groups exhibited group-by-time interaction (p < 0.001). After adjusting for confounding factors, the mean BMD was significantly different at the 24-month and the 48-month follow-up (p = 0.049, p < 0.001, respectively). Subgroup analysis after adjusting for confounding factors showed a mean BMD of 1.128 and 1.104 at baseline, 1.110 and 1.100 at the 24-month follow-up, and 1.106 and 1.065 at the 48-month follow-up for persistent atrophic and non-atrophic gastritis groups, respectively. The difference between mean BMD was not significant at baseline (p = 0.171), but was significant at the 24-month and 48-month follow-ups (p = 0.044 and p < 0.001, respectively). Absolute changes in BMD over 48 months were - 0.010 and - 0.051 for the two subgroups, which was significantly different (p < 0.001). Atrophic gastritis reduces BMD in premenopausal women in their 40s. Patients with atrophic gastritis exhibited lower BMD than patients without, and patients with persistent atrophic gastritis exhibited a greater decrease in BMD.

Oestrogen replacement improves bone mineral density in oligo-amenorrhoeic athletes: a randomised clinical trial

OBJECTIVE

Normal-weight oligo-amenorrhoeic athletes (OAA) are at risk for low bone mineral density (BMD). Data are lacking regarding the impact of oestrogen administration on bone outcomes in OAA. Our objective was to determine the effects of transdermal versus oral oestrogen administration on bone in OAA engaged in weight-bearing activity.

METHODS

121 patients with OAA aged 14-25 years were randomised to receive: (1) a 17β-estradiol transdermal patch continuously with cyclic oral micronised progesterone (PATCH), (2) a combined ethinyl estradiol and desogestrel pill (PILL) or (3) no oestrogen/progesterone (NONE). All participants received calcium and vitamin D supplementation. Areal BMD was assessed at the lumbar spine, femoral neck, total hip and total body less head using dual-energy X-ray absorptiometry at baseline, 6 and 12 months. Intention-to-treat (ITT) and completers analyses were performed.

RESULTS

Randomised groups did not differ for age, body mass index or BMD Z-scores at baseline. For ITT analysis, spine and femoral neck BMD Z-scores significantly increased in the PATCH versus PILL (p=0.011 and p=0.021, respectively) and NONE (p=0.021 and p=0.033, respectively) groups, and hip BMD Z-scores significantly increased in the PATCH versus PILL group (p=0.018). Similar findings were noted in completers analysis.

CONCLUSION

Transdermal estradiol over 12 months improves BMD in young OAA, particularly compared with an ethinyl estradiol-containing contraceptive pill/oral contraceptives.

TRIAL REGISTRATION NUMBER

NCT00946192; Pre-results.

Total flavonoid extract of Epimedium herb increases the peak bone mass of young rats involving enhanced activation of the AC10/cAMP/PKA/CREB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedium sagittatum brevicornum Maxim. is an important traditional Chinese herb that has long been used to promote bone fracture healing and treat osteoporosis.

AIM OF THE STUDY

Achieving peak bone mass by adolescence has now been accepted to be fundamental for preventing osteoporosis in adulthood life. This study investigated the possibility of increasing peak bone mass in young rats using the total flavonoid extract of Epimedium herb (TFE).

MATERIALS AND METHODS

TFE was intragastrically administered to one-month-old Wistar rats at a low (100 mg/kg), middle (200 mg/kg) or high dose (400 mg/kg). Whole body bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry every two weeks. When BMD of any one of TFE groups was found to be significantly higher than that of the control, all rats were sacrificed, serum samples were collected for bone turnover biochemical assays, and femurs, tibiae and vertebrae were isolated and used in BMD, mechanical, micro-structural, histomorphometric and mechanistic studies.

RESULTS

Administration of TFE at middle and high doses for two months significantly increased the whole body, femoral and vertebral BMDs, and improved the bone mechanical and micro-architectural properties. The serum turnover biochemical results and the enhanced expression levels of bone-formation regulatory genes (Runx-2, OSX, and BMP-2) demonstrated that TFE administration increased bone formation but had no effect on bone resorption. The increased phosphorylation levels in femurs of PKA and CREB and expression of AC10 (the only soluble form of adenylyl cyclase) and the increased serum cAMP level after 4 h of TFE administration indicated that TFE promoted bone formation by activating the AC10/cAMP/PKA/CREB pathway in vivo.

CONCLUSIONS

Oral administration of TFE at 200 mg/kg for two months can increase the peak bone mass of growing rats, suggesting the possibility of using total flavonoid extract of Epimedium herb to increase the peak bone mass in adolescence which is important for preventing osteoporosis in adult life.

PLS3 Mutations in X-Linked Osteoporosis: Clinical and Bone Characteristics of Two Novel Mutations

BACKGROUND AND OBJECTIVES

Plastin 3 (PLS3) mutations are associated with an X-linked osteoporosis. Here we describe two new families with novel mutations, including one with a whole gene PLS3 deletion, and review the literature on 9 previously reported cases.

RESULTS

Hemizygous male carriers presented with multiple peripheral bone fractures, low bone mineral density (BMD), and vertebral compression fractures. Heterozygous female carriers did not have a history of fragility fractures, although 1 individual presented with low BMD. Apart from greyish-tinged sclera, no other extraskeletal features of osteogenesis imperfecta were identified. Histomorphometry from a transiliac bone biopsy in one of our index patients demonstrated significantly low trabecular bone volume with increased bone turnover. Bisphosphonate treatment was associated with a reduction in the fracture rate and increased bone density.

CONCLUSION

Hemizygous mutations in PLS3 may cause a monogenic form of X-linked osteoporosis presenting in childhood with a nonspecific phenotype. No characteristic ocular, dental, or joint abnormalities are defined. When genetic testing is undertaken to investigate for primary causes of bone fragility, we suggest PLS3 be included in order not to miss this diagnosis.

How Is Adolescent Bone Mass and Density Influenced by Early Life Body Size and Growth? The Tromsø Study: Fit Futures-A Longitudinal Cohort Study From Norway

The effect of birth weight and childhood body mass index (BMI) on adolescents’ bone parameters is not established. The aim of this longitudinal, population‐based study was to investigate the association of birth weight, childhood BMI, and growth, with adolescent bone mass and bone density in a sample of 633 adolescents (48% girls) from The Tromsø Study: Fit Futures. This population‐based cohort study was conducted in 2010–2011 and 2012–2013 in Tromsø, Norway. Bone mineral content (BMC) and areal BMD (aBMD) were measured at total hip (TH) and total body (TB) by dual‐energy X‐ray absorptiometry (DXA) and converted to internal Z‐scores. Birth weight and childhood anthropometric measurements were retrospectively obtained from the Medical Birth Registry of Norway and childhood health records. Associations between birth weight, BMI, and growth were evaluated by fitting linear mixed models with repeated measures of BMC and aBMD at ages 15 to 17 and 18 to 20 years as the outcome. In crude analysis, a significant positive association (p < 0.05) with TB BMC was observed per 1 SD score increase in birth weight, observed in both sexes. Higher rate of length growth, conditioned on earlier size, from birth to age 2.5 years, and higher rate of weight gain from ages 6.0 to 16.5 years, conditioned on earlier size and concurrent height growth, revealed stronger associations with bone accrual at ages 15 to 20 years compared with other ages. Compared with being normal weight, overweight/obesity at age 16.5 years was associated with higher aBMD Z‐scores: β coefficient (95% confidence interval [CI]) of 0.78 (0.53, 1.03) and 1.08 (0.85, 1.31) in girls, 0.63 (0.42, 0.85) and 0.74 (0.54, 0.95) in boys at TH and TB, respectively. Similar associations were found for BMC. Being underweight was consistently negatively associated with bone parameters in adolescence. In conclusion, birth weight influences adolescent bone mass but less than later growth and BMI in childhood and adolescence. © 2018 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

Heavy Episodic Drinking Is Associated With Poorer Bone Health in Adolescent and Young Adult Women

OBJECTIVE

Osteoporosis is a costly bone disease characterized by low bone mineral density (BMD) that primarily affects postmenopausal women. One factor that may lead to osteoporosis is a failure to reach peak bone mass (PBM) in early adulthood. In older adults and animal models, heavy episodic drinking (HED) has been found to predict failure to reach PBM. However, this relationship has yet to be investigated in adolescent human females.

METHOD

Female college students (N = 87; 60% White) reported age at menarche, hormonal contraceptive use, physical activity, smoking habits, and HED history via an online survey and then received a dual energy x-ray absorptiometry bone scan to assess both lean body mass and BMD at the lumbar spine.

RESULTS

Frequent HED (having four or more drinks within 2 hours on 115 or more occasions since the start of high school, which is approximately equal to 1.6 episodes per month over this period) was associated with decreased vertebral BMD even when variables most commonly associated with bone health (lean body mass, physical activity, age at menarche, smoking, and oral contraception use) were controlled for. However, early HED initiation (beginning HED at age 15 years or younger) was not significantly related to BMD.

CONCLUSIONS

This is the first study to assess the impacts of early HED initiation and frequent HED during adolescence on the bone health of young women. Results suggest frequency of HED before reaching PBM, but not age at initiation, may be negatively related to skeletal health during young adulthood. These findings encourage research into the association between HED and BMD in late adolescence.

Sexual Dimorphism and the Origins of Human Spinal Health

Recent observations indicate that the cross-sectional area (CSA) of vertebral bodies is on average 10% smaller in healthy newborn girls than in newborn boys, a striking difference that increases during infancy and puberty and is greatest by the time of sexual and skeletal maturity. The smaller CSA of female vertebrae is associated with greater spinal flexibility and could represent the human adaptation to fetal load in bipedal posture. Unfortunately, it also imparts a mechanical disadvantage that increases stress within the vertebrae for all physical activities. This review summarizes the potential endocrine, genetic, and environmental determinants of vertebral cross-sectional growth and current knowledge of the association between the small female vertebrae and greater risk for a broad array of spinal conditions across the lifespan.

Proceedings of the 2017 Santa Fe Bone Symposium: Insights and Emerging Concepts in the Management of Osteoporosis

The 18th Annual Santa Fe Bone Symposium was held on August 4-5, 2017, in Santa Fe, New Mexico, USA. The symposium convenes health-care providers and clinical researchers to present and discuss clinical applications of recent advances in research of skeletal diseases. The program includes lectures, oral presentations by endocrinology fellows, case-based panel discussions, and breakout sessions on topics of interest, with emphasis on participation and interaction of all participants. Topics included the evaluation and treatment of adult survivors with pediatric bone diseases, risk assessment and management of atypical femur fractures, nonpharmacologic strategies in the care of osteoporosis, and skeletal effects of parathyroid hormone with opportunities for therapeutic intervention. Management of skeletal complications of rheumatic diseases was discussed. Insights into sequential and combined use of antiresorptive agents were presented. Individualization of patient treatment decisions when clinical practice guidelines may not be applicable was covered. Challenges and opportunities with osteoporosis drug development were discussed. There was an update on progress of Bone Health TeleECHO (Bone Health Extension for Community Healthcare Outcomes), a teleconferencing strategy for sharing knowledge and expanding capacity to deliver best-practice skeletal health care.

Longitudinal determinants of 12-month changes on bone health in adolescent male athletes

We identified the determinants of 12-month changes of areal bone mineral density (aBMD), hip geometry and trabecular bone score (TBS) in adolescent male athletes. Changes in region-specific lean mass and the type of sport are the most consistent determinants in this population.

PURPOSE

This study aims to identify the determinants of 12-month changes of areal bone mineral density (aBMD), hip geometry and trabecular bone score (TBS) in adolescent male athletes.

METHODS

The sample was 104 adolescent males aged 12-14 years at baseline that were followed over 12 months: 39 swimmers, 37 footballers (or soccer players) and 28 cyclists. Dual-energy X-ray absorptiometry measured aBMD at the whole body, lumbar spine and dual hip. Hip geometry estimates at the femoral neck were measured using hip structural analysis. Lumbar spine texture was measured by TBS.

RESULTS

Multivariate regression models significantly explained 38-60% of the variance in the aBMD changes, 36-62% in the hip geometry estimates changes and 45% in the TBS changes. Δregion-specific lean mass was the most consistent predictor of changes in aBMD outcomes (β = 0.591 to 0.696), followed by cycling participation (β = - 0.233 to - 0.262), swimming participation (β = - 0.315 to - 0.336) and ΔMVPA (β = 0.165). Cycling participation was the most consistent predictor of changes in hip geometry estimates (β = - 0.174 to - 0.268), followed by Δregion-specific lean mass (β = 0.587) and Δcardiorespiratory fitness (β = 0.253). Finally, cycling and swimming participation (β = - 0.347 to - 0.453), Δregion-specific lean mass (β = 0.848) and Δstature (β = 0.720) were predictors of change in TBS.

CONCLUSIONS

Changes in region-specific lean mass and the type of sport are the most consistent determinants of 12-month changes in aBMD, hip geometry estimates and TBS in adolescent male athletes.

TRIAL REGISTRATION

ISRCTN17982776.

Safety and Feasibility of Antiretroviral Preexposure Prophylaxis for Adolescent Men Who Have Sex With Men Aged 15 to 17 Years in the United States

IMPORTANCE

Adolescents represent a key population for implementing preexposure prophylaxis (PrEP) interventions worldwide, yet tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for PrEP is only licensed for adults.

OBJECTIVE

To examine the safety of and adherence to PrEP along with changes in sexual risk behavior among adolescent men who have sex with men (MSM).

DESIGN, SETTING, AND PARTICIPANTS

Adolescent Medicine Trials Network for HIV/AIDS Interventions 113 (Project PrEPare) was a PrEP demonstration project that evaluated the safety, tolerability, and acceptability of TDF/FTC and patterns of use, rates of adherence, and patterns of sexual risk behavior among healthy young MSM aged 15 to 17 years. Participants were recruited from adolescent medicine clinics and their community partners in 6 US cities, had negative test results for human immunodeficiency virus (HIV) but were at high risk for acquiring an infection, and were willing to participate in a behavioral intervention and accept TDF/FTC as PrEP.

EXPOSURES

All participants completed an individualized evidence-based behavioral intervention and were provided with daily TDF/FTC as PrEP for 48 weeks.

MAIN OUTCOMES AND MEASURES

The main objectives were to: (1) provide additional safety data regarding TDF/FTC use among young MSM who had negative test results for HIV; (2) examine the acceptability, patterns of use, rates of adherence, and measured levels of tenofovir diphosphate in dried blood spots; and (3) examine patterns of risk behavior when young MSM were provided with a behavioral intervention in conjunction with open-label TDF/FTC.

RESULTS

Among 2864 individuals screened (from August 2013 to September 2014), 260 were eligible and 78 were enrolled (mean [SD] age, 16.5 [0.73] years), of whom 2 (3%) were Asian/Pacific Islander, 23 (29%) were black/African American, 11 (14%) were white, 16 (21%) were white Hispanic, and 26 (33%) were other/mixed race/ethnicity. Over 48 weeks of PrEP use, 23 sexually transmitted infections were diagnosed in 12 participants. The HIV seroconversion rate was 6.4 (95% CI: 1.3-18.7) per 100 person-years. Tenofovir diphosphate levels consistent with a high degree of anti-HIV protection (>700 fmol/punch) were found in 42 (54%), 37 (47%), 38 (49%), 22 (28%), 13 (17%), and 17 (22%) participants at weeks 4, 8, 12, 24, 36, and 48, respectively.

CONCLUSIONS AND RELEVANCE

Adolescent Medicine Trials Network for HIV/AIDS Interventions 113 enrolled a diverse sample of adolescent MSM at risk for HIV who consented to study participation. Approximately half achieved protective drug levels during the monthly visits, but adherence decreased with quarterly visits. Youth may need additional contact with clinical staff members to maintain high adherence.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01769456.

Longitudinal Adaptations of Bone Mass, Geometry, and Metabolism in Adolescent Male Athletes: The PRO-BONE Study

Adolescence is a crucial period for bone development, and exercise can enhance bone acquisition during this period of life. However, it is not known how the different loading sports practiced can affect bone acquisition in adolescent male athletes. Therefore, the purpose of the present study was to determine the 1-year longitudinal bone acquisition among adolescent males involved in osteogenic (football) and non-osteogenic (swimming and cycling) sports and to compare with active controls. A total of 116 adolescent males aged 12 to 14 years at baseline were followed for 1 year: 37 swimmers, 37 footballers, 28 cyclists, and 14 active controls. Bone mineral content (BMC) was assessed using dual-energy X-ray absorptiometry (DXA); cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), and section modulus (Z) at the femoral neck was assessed using hip structural analysis (HSA); and bone texture of the lumbar spine was assessed using trabecular bone score (TBS). Serum N-terminal propeptide of procollagen type I (PINP), isomer of the Carboxi-terminal telopeptide of type 1 collagen (CTX-I), total serum calcium, and 25 hydroxyvitamin D [25(OH)D] were analyzed. Footballers had significantly higher adjusted BMC at the lumbar spine (7.0%) and femoral neck (5.0%) compared with cyclists, and significantly greater BMC at the lumbar spine (6.9%) compared with swimmers. Footballers presented significantly greater TBS (4.3%) compared with swimmers, and greater CSMI (10.2%), CSA (7.1%), Z (8.9%) and TBS (4.2%) compared with cyclists. No differences were noted between cyclists and swimmers, both groups had similar bone acquisition compared with controls. PINP was significantly higher in footballers and controls compared with cyclists and swimmers (3.3% to 6.0%), and 25(OH)D was significantly higher in footballers and cyclists compared with swimmers and controls (9.9% to 13.1%). These findings suggest that bone acquisition is higher in adolescent male footballers compared with swimmers and cyclists at the femoral neck and lumbar spine sites of the skeleton. © 2017 American Society for Bone and Mineral Research.

The effect of 12-month participation in osteogenic and non-osteogenic sports on bone development in adolescent male athletes. The PRO-BONE study

OBJECTIVES

Research investigating the longitudinal effects of the most popular sports on bone development in adolescent males is scarce. The aim is to investigate the effect of 12-month participation in osteogenic and non-osteogenic sports on bone development.

DESIGN

A 12-month study was conducted in adolescent males involved in football, swimming and cycling and compared with an active control group.

METHODS

116 adolescent males (13.1±0.1years at baseline): 37 footballers, 37 swimmers, 28 cyclists and 14 active controls were followed for 12 months. Bone mineral content (BMC) was measured by dual-energy X-ray absorptiometry, and bone stiffness was measured by quantitative ultrasound. Bone outcomes at 12 months were adjusted for baseline bone status, age, height, lean mass and moderate to vigorous physical activity.

RESULTS

Footballers had higher improvement in adjusted BMC at the total body, total hip, shaft, Ward's triangle, legs and bone stiffness compared to cyclists (6.3-8.0%). Footballers had significantly higher adjusted BMC at total body, shaft and legs compared to swimmers (5.4-5.6%). There was no significant difference between swimmers and cyclists for any bone outcomes. Swimming and cycling participation resulted in non-significant lower bone development at most sites of the skeleton compared to controls (-4.3 to -0.6%).

CONCLUSIONS

Football participation induces significantly greater improvements in BMC and bone stiffness over 12 months compared to cycling and swimming.

CLINICAL TRIAL REGISTRATION

ISRCTN17982776.

Progressive skeletal benefits of physical activity when young as assessed at the midshaft humerus in male baseball players

Physical activity benefits the skeleton, but there is contrasting evidence regarding whether benefits differ at different stages of growth. The current study demonstrates that physical activity should be encouraged at the earliest age possible and be continued into early adulthood to gain most skeletal benefits.

INTRODUCTION

The current study explored physical activity-induced bone adaptation at different stages of somatic maturity by comparing side-to-side differences in midshaft humerus properties between male throwing athletes and controls. Throwers present an internally controlled model, while inclusion of control subjects removes normal arm dominance influences.

METHODS

Throwing athletes (n = 90) and controls (n = 51) were categorized into maturity groups (pre, peri, post-early, post-mid, and post-late) based on estimated years from peak height velocity (<-2, -2 to 2, 2 to 4, 4 to 10, and >10 years). Side-to-side percent differences in midshaft humerus cortical volumetric bone mineral density (Ct.vBMD) and bone mineral content (Ct.BMC); total (Tt.Ar), medullary (Me.Ar), and cortical (Ct.Ar) areas; average cortical thickness (Ct.Th); and polar Strength Strain Index (SSI_P) were assessed.

RESULTS

Significant interactions between physical activity and maturity on side-to-side differences in Ct.BMC, Tt.Ar, Ct.Ar, Me.Ar, Ct.Th, and SSI_P resulted from the following: (1) greater throwing-to-nonthrowing arm differences than dominant-to-nondominant arm differences in controls (all p < 0.05) and (2) throwing-to-nonthrowing arm differences in throwers being progressively greater across maturity groups (all p < 0.05). Regional analyses revealed greatest adaptation in medial and lateral sectors, particularly in the three post-maturity groups. Years throwing predicted 59% of the variance of the variance in throwing-to-nonthrowing arm difference in SSI_P (p < 0.001).

CONCLUSION

These data suggest that physical activity has skeletal benefits beginning prior to and continuing beyond somatic maturation and that a longer duration of exposure to physical activity has cumulative skeletal benefits. Thus, physical activity should be encouraged at the earliest age possible and be continued into early adulthood to optimize skeletal benefits.

Bone modeling, remodeling, and skeletal health in children and adolescents: mineral accrual, assessment and treatment

The modeling and remodeling process of the bone is fundamental to maintaining its integrity and mechanical properties. Many physical and biochemical factors during childhood and adolescence are crucially important for the development of healthy bones. Systemic conditions, such as hormonal status, nutrition, physical inactivity, or many pharmacological treatments, as well as a local variation in the load, can influence bone turnover and, consequently, the attainment of a proper peak bone mass. However, many diseases affecting children and adolescents can be associated with a reduction in bone accrual or a loss of bone mass and quality, which leads to an increased risk of fracture over one's life. In this review, we examine the effects of genetics, physical activity, chronic diseases and pharmacological treatments, and dietary factors on bone integrity in children and adolescents. We also briefly describe the specific tools that are currently used in assessing bone health.