The Determinants of Peak Bone Mass

Serum bone turnover markers were associated with bone mass in late prepuberty and early puberty

AIM

To analyse the association between bone turnover markers and bone mass in children and young adults.

METHODS

This descriptive study followed 132 children (68 boys/64 girls) from Malmö, Sweden, as controls in a school-based intervention study (2000-2017). Height, weight, Tanner stage and bone mass were measured annually from ages 8 to 15 years, with follow-ups at 19 and 23 years of age. Serum markers for bone formation (bone-specific alkaline phosphatase (bALP), N-terminal propeptide of collagen type 1 (PINP), osteocalcin) and resorption (C-terminal telopeptide crosslinks (CTX), tartrate-resistant acid phosphatase (TRAcP 5b)) were collected at ages 9.9 ± 0.6 (mean ± SD) (n = 78), 12.0 ± 0.6 (n = 64), 14.9 ± 0.8 (n = 52), 18.8 ± 0.3 (n = 34) and 23.3 ± 0.6 years (n = 56).

RESULTS

Compared to girls, boys showed higher bone turnover markers at ages 15, 19 and 23 years (all p < 0.05). At 10 years of age (Tanner stage 1 and 2), bALP and TRAcP 5b correlated with current bone mass (adjusted for age and sex), while bALP, PINP, osteocalcin and CTX correlated with bone mass change over the next 2 years (adjusted for age, sex and interval) (all p < 0.05).

CONCLUSION

Bone turnover markers in early Tanner stages predicted both current bone mass and subsequent bone mass changes.

The Determinants of Bone Health in Children With Autism Spectrum Disorder: A Systematic Narrative Review

Autism spectrum disorder (ASD) is a complex disorder associated with social and communication impairments and repetitive and restrictive behavioural patterns. Children with ASD often present with concurrent conditions, including poor bone health, which affect long-term health. Although there is compelling evidence to suggest that children with ASD have poorer bone traits than typically developing children, the primary factors associated with these differences are unclear. This review will explore the potential role that factors such as physical activity, nutrition (calcium, protein, vitamin C, vitamin D) and lifestyle (sleep, medication) play on bone health in children with ASD. Having a greater understanding of the influencing factors of low BMD and how these might interact in a synergistic manner in ASD children will provide an opportunity to develop targeted interventions to improve bone health aiming to avert attainment of suboptimal peak bone mass which may lead to early onset osteoporosis, fracture and muscle deconditioning in this paediatric population.

EFFECTS OF COMBINED HORMONAL CONTRACEPTIVES (CHC) ON BONE HEALTH IN ADOLESCENT GIRLS - A SYSTEMATIC REVIEW

OBJECTIVES

To summarize the effects of combined hormonal contraceptives (CHC) on bone health in adolescent girls.

DESIGN

A systematic search was performed using the following databases: Medline, EMBASE, CINAHL and Cochrane Library clinical trials register, from inception to July 2024.

ELIGIBILITY

Intervention and cohort studies that assessed the use of CHC on bone health in adolescent girls aged 10-19years old were included.

DATA SYNTHESIS

Four randomized control trials and eight observational studies (n =2689) were included.

CONCLUSION

Current evidence indicates that the use of CHC in post-menarchal adolescent girls reduce bone accrual compared to non-users. The negative impact on bone accrual is likely related to the estrogen dose in the CHC preparation, the regimen used and the duration of use.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD 42024574905 on 31 July 2024.

Proteins and pathways involved in inflammation are longitudinally associated with total body bone mineral density among primarily Hispanic overweight/obese adolescents and young adults

BMD, an important marker of bone health, is regulated by a complex interaction of proteins. Plasma proteomic analyses can contribute to identification of proteins associated with changes in BMD. This may be especially informative in stages of bone accrual and peak BMD achievement (ie, adolescence and young adulthood), but existing research has focused on older adults. This analysis in the Study of Latino Adolescents at Risk for Type 2 Diabetes (SOLAR; n = 304; baseline age 8-13, 100% Hispanic) explored associations between baseline proteins (n = 653 proteins) measured with Olink plasma protein profiling and repeated annual DXA measures of BMD (average of 3.2 visits per participant). Covariate-adjusted linear mixed effect regression models were applied to estimate longitudinal protein-BMD associations using an adjusted p value cutoff (p < .00068). Identified proteins were imported into the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database to determine significantly enriched protein pathways. Forty-four proteins, many of which are involved in inflammatory processes, were associated with longitudinal changes in total body BMD, including several proteins previously linked to bone health such as osteopontin (SPP1) and microfibrillar-associated protein 5 (MFAP5; both p < .00068). These 44 proteins were associated with enrichment of pathways including PI3K-Akt signaling pathway and cytokine-cytokine receptor interaction, supporting results from existing proteomics analyses in older adults. To evaluate whether protein associations were consistent into young adulthood, linear mixed effect models were repeated in a young adult cohort (n = 169; baseline age 17-22; 62.1% Hispanic) with 346 available overlapping Olink protein measures. While there were no significant overlapping longitudinal protein associations between the cohorts, these findings suggest differences in protein regulation at different ages and provide novel insight on longitudinal protein associations with BMD in overweight/obese adolescents and young adults of primarily Hispanic origin, which may inform the development of biomarkers for bone health in youth.

Preterm birth and risk of bone fractures during childhood and early adulthood

People born preterm have reduced BMD, subnormal peak bone mass, and an increased risk of osteoporosis. Whether this translates to increased risk of bone fractures is uncertain. We assessed fracture risk from childhood to early adulthood in relation to gestational age and sex by conducting a nationwide register-linkage cohort study comprising all 223 615 liveborn (January 1987-September 1990) singletons (9161, 4.1%; preterm) in Finland. Cox regression models provided hazard ratios (HRs) for fracture diagnosis in public specialty health care in both first and recurrent event settings during the whole follow-up (0-29 years) and during different age periods (0-4, 5-9, 10-29 years). Gestational age was considered categorical (full-term, 39-41 weeks; reference). A total of 39 223 (17.5%) children or young adults had at least 1 fracture. In analyses not stratified by sex, only extremely preterm birth (<28 completed weeks' gestation) was associated with risk of bone fracture at 0-29 years (adjusted HR [aHR]: 0.46; 95% CI: 0.28-0.74) compared with those born full-term. Among females, gestational age was unrelated to fracture risk at 0-29 years. Among males, extremely and very preterm (28-31 weeks) birth was associated with lower risk of fracture at 0-29 years compared with those born full-term (aHR: 0.38 [95% CI: 0.21-0.71] and 0.75 [95% CI: 0.59-0.95], respectively). Restricting the analyses to the individuals without severe medical condition(s) attenuated the associations. However, the fracture risk varied according age and sex: at 10-29 years, moderately preterm (32-33 weeks) females and extremely and very preterm males had a lower risk (aHR: 0.63 [0.43-0.94], 0.35 [0.17-0.69], and 0.74 [0.57-0.95], respectively), while late-preterm birth (34-36 weeks) was associated with a 1.6-fold higher risk among females at 0-5 years, and a 1.4-fold risk among males at 5-10 years. Analyses on recurrent fractures showed a similar pattern. Children and young adults, in particular males, born extremely or very preterm may have fewer bone fractures; this is partly explained by severe medical conditions in this group.

The association between blood cadmium levels and bone mineral density in U.S. adolescents aged 12-19 years

According to the multivariable adjusted models, there was an inverse association between B-Cd levels and BMD, which was particularly evident in the subgroup analyses of other Hispanic and female individuals in the adolescent population. Clinicians and policy-makers should thoroughly consider the genetic implications of B-Cd levels in relation to BMD during the prevention and treatment of osteoporosis.

OBJECTIVE

To investigate the associations between blood cadmium (B-Cd) levels and bone mineral density (BMD) in adolescents.

METHODS

On the basis of the National Health and Nutrition Examination Survey (NHANES) database spanning from 2011 to 2018, we used weighted multiple regression, a generalized weighted model and smoothed curve methods to investigate the associations between B-Cd levels and BMD in adolescents. Subgroup analyses were also conducted to examine potential differences across age, sex, race, tobacco exposure status and other relevant variables.

RESULTS

Among the 2427 participants, 52% were males, and 48% were females. In this study, multistage sampling data from the NHANES database were analysed, and the positive association between B-Cd levels and BMD shifted to a negative association after adjustment for age, sex and race. Subgroup analyses revealed a more pronounced association among females (β =  - 0.07, 95% CI: - 0.09, - 0.04, P < 0.001), other Hispanic individuals (β =  - 0.08, 95% CI: - 0.14, - 0.02, P = 0.012) and individuals exposed to tobacco (β =  - 0.04, 95% CI: - 0.06, - 0.01, P = 0.016).

CONCLUSION

The findings revealed a negative association between B-Cd levels and BMD in multivariable adjusted models.

Between a Rock and a Short Place-The Impact of Nephrolithiasis on Skeletal Growth and Development Across the Lifespan

PURPOSE OF REVIEW

The impact of nephrolithiasis on skeletal growth and bone health across the life span of kidney stone formers is reviewed.

MAIN FINDINGS

Bone disease is an early event among kidney stone formers (SF), with distinct phenotypes according to each age, sex, menopausal status, dietary, hormonal and genetic factors. Nephrolithiasis-associated bone disorder is characterized by reduced bone mineral density (BMD) and histologically discloses low bone formation, high bone resorption and abnormal mineralization. Although hypercalciuria has been presumed to be pathogenic for bone loss in SF, the association of BMD with urinary calcium is not uniform in all studies. Hypocitraturia, metabolic disturbances, cytokines and receptors, growth factors and acid-base status may all influence skeletal outcomes. The potential link of bone disease with vascular calcification and cardiovascular disease among SF is discussed. The unique vulnerability of the younger skeleton to the effects of nephrolithiasis on attainment of peak bone mass and strength is highlighted and the association of bone loss with kidney stone formation early in life indicate the opportunity for intervention to reduce the risk of future bone fractures.

Does higher serum 25-hydroxyvitamin D levels will harm bone mineral density?: a cross-sectional study

OBJECTIVE

Vitamin D plays a critical role in the prevention and management of osteoporosis. However, there is an ongoing debate regarding the most effective vitamin D supplementation strategies for maintaining optimal bone mineral density (BMD) levels in adults. This study sought to establish the correlation between serum 25-hydroxyvitamin D [25(OH)D] levels and total BMD in a substantial population sample.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) for the 2011-2018 cycles, encompassing 11,375 adult participants, were analyzed. The primary variables of interest were serum 25(OH)D levels and BMD. A multivariable logistic regression model was utilized to account for relevant variables associated with these correlations.

RESULTS

A U-shaped relationship between serum 25(OH)D levels and BMD was observed. In males, a significant positive association was identified for 25(OH)D levels below 84.8 nmol/L (p < 0.0001), while levels above this threshold showed no significant correlation (p = 0.3377). In females, those with 25(OH)D levels below 31.4 nmol/L exhibited a significant positive association with BMD (p = 0.0010), but this association weakened and became marginally significant above this threshold (p = 0.0650).

CONCLUSIONS

For adult males, the optimal serum 25(OH)D level is 84.8 nmol/L, beyond which higher levels do not lead to increased BMD. A deficiency threshold for adult females should be above 31.4 nmol/L, as lower 25(OH)D levels are not conducive to BMD. These findings underscore the importance of maintaining appropriate vitamin D levels for bone health in both genders.

Dietary patterns and bone density among school-aged children: a cross-sectional study in China

BACKGROUND

Diet is an essential modifiable determinant of bone health, yet the associations between dietary patterns (DPs) and bone mineral density (BMD) in Chinese children remain limited.

OBJECTIVE

This study aimed to investigate the relationship between overall diet and low BMD risk among school-aged children in China.

METHODS

A total of 1,099 children aged 9-12 in China were recruited for this cross-sectional study. A semi-quantified food frequency questionnaire (FFQ) was used to assess dietary intake. A priori numerical index, the Chinese Dietary Guidelines Index for Children and Adolescents [CDGI (2021)-C] was utilized to assess dietary quality. Specific DPs were identified by using principal components analysis (PCA). The BMD of the left forearm was assessed using dual-energy X-ray absorptiometry (DXA). Spearman correlation test was conducted to investigate the associations between DPs. Multivariate logistic regression analysis and restricted cubic spline models (RCS) were applied to explore the associations between DPs and BMD.

RESULTS

Three distinct DPs were identified: the plant-animal balanced pattern, the grain-tuber-meat pattern, and the bean-dairy pattern. We found a weak but significant positive correlation of the CDGI (2021)-C with the plant-animal balanced pattern (R = 0.318, P < 0.001), and with the bean-dairy pattern (R = 0.266, P < 0.001), respectively. After adjusting for covariates, adherence to the CDGI (2021)-C (Q4 vs. Q1, OR = 0.45, 95% CI: 0.27-0.75), the plant-animal balanced pattern (Q4 vs. Q1, OR = 0.50, 95% CI: 0.31-0.81), and the bean-dairy pattern (Q3 vs. Q1, OR = 0.57, 95% CI: 0.33-0.96) were associated with a lower risk of low BMD. No significant association was observed between the grain-tuber-meat pattern and low BMD (Q4 vs. Q1, OR = 1.09; 95% CI: 0.90-1.31).

CONCLUSION

Adherence to the CDGI (2021)-C and the plant-animal balanced pattern is advantageous for bone health and inversely correlated with the risk of low BMD among school-aged children in China. Additionally, moderate adherence to the bean-dairy pattern may also confer benefits to bone health. A balanced and overall healthy diet should be recommended in our daily life.

Mid-Childhood Plasma Concentrations of Per- and Polyfluoroalkyl Substances, Modifiable Lifestyle Factors, and Bone Mineral Density Through Late Adolescence

There is limited research on associations of per- and polyfluoroalkyl substances (PFAS) with areal bone mineral density (aBMD) through adolescence and whether bone-strengthening factors ameliorate effects. In the Project Viva cohort (N = 484; 50% female), we used sex-stratified linear regression and quantile g-computation mixture models to examine associations of mid-childhood (median: 7.8 years; 2007-2010) plasma PFAS concentrations with a dual-energy X-ray absorptiometry total-body aBMD Z-score in early and late adolescence (median: 12.9 and 17.6 years, respectively). We explored stratum-specific estimates by parent/self-reported physical activity and dairy intake. Using linear mixed models, we evaluated associations with aBMD accrual from mid-childhood through late adolescence. Females with higher perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA) had lower early adolescent aBMD Z-score [e.g., β(95%CI)] per doubling PFOA: -0.19(-0.41, 0.03)]. Youth with higher PFOA and PFDA had lower late adolescent aBMD Z-score, but CIs were wide [e.g., PFOA: females, -0.12(-0.40, 0.16); males, -0.10(-0.42, 0.21)]. Mixture models generally corroborated single PFAS results, and in linear mixed models, females with higher PFAS concentrations, and males with higher PFOA, had slower aBMD accrual. Less active males with higher PFOA, PFDA, and the PFAS mixture had lower late adolescent aBMD Z-score. Some PFAS appeared more negatively associated with the aBMD Z-score among those who consumed less dairy, but there was not consistent evidence of effect modification. Exposure to select PFAS may affect bone accrual through adolescence, with possible resilience conferred by greater physical activity and dairy intake.

Associations of ethnicity, skin tone, and genome-wide sequencing with bone mineral density in adolescents

BACKGROUND

Dual-energy x-ray absorptiometry reference data designate Black and non-Black categories, as higher BMD has been documented among Black youth. We examined associations of race, skin tone, and genetic factors with bone mineral density (BMD).

METHODS

557 adolescents were followed longitudinally. Exposures included race, skin tone, and principal components (PC) from genome-wide arrays. Total body BMD Z-score (BMD-Z) was the primary outcome using linear regression.

RESULTS

359 adolescents identified as non-Hispanic White (NHW) and 75, non-Hispanic Black (NHB). BMD-Z was higher in NHB vs. NHW (β: 0.92 units, 95% CI: 0.64, 1.19) or those with darker skin (0.79, 95% CI: 0.49, 1.08 for brown vs. medium). The first genetic PC (PC1) correlated with identification as NHB. PC1 was associated with higher BMD-Z (0.09, 95% CI: 0.06, 0.12), even after including race (0.07, 95% CI: 0.00, 0.14) or skin tone (0.10, 95% CI: 0.05, 0.15); both race (0.26, 95% CI: -0.49, 1.01 for NHB vs. NHW) and skin tone (-0.08, 95% CI: -0.59, 0.44 for brown vs. medium) no longer predicted BMD-Z after adjustment for PC1.

CONCLUSION

Genetic similarity was robustly associated with BMD, prompting a reevaluation of adolescent BMD reference data to exclude the consideration of race.

IMPACT

Current bone density reference databases include a binary assignment of patients into "Black" and "non-Black" categories, as a higher BMD has been documented among those identifying as Black compared with individuals of other racial and ethnic backgrounds. This study found genetic similarity to be more strongly associated with bone density by dual-energy x-ray absorptiometry than race or skin tone. These data emphasize a need to reevaluate how bone density measurements are interpreted, including exploring reference data that exclude the consideration of race.

Association between dietary copper intake and bone mineral density in children and adolescents aged 8-19 years: A cross-sectional study

PURPOSE

Some studies showed the possible role of copper intake on bone mineral density (BMD) in adults or the elderly, but the association remained uncertain in children and adolescents. Our research explored the association between copper intake and BMD in individuals aged 8-19 years from the National Health and Nutrition Examination Survey (NHANES) 2011-2016.

METHODS

In the present study, 6,965 individuals aged 8-19 (mean age 13.18 ± 3.38 years) were enrolled from the NHANES 2011-2016. Copper intake was evaluated by averaging two 24-hour copper dietary intake recalls. Multivariate linear regression analyses were used to explore the association between copper intake and total BMD, subtotal BMD, and total spine BMD in children and adolescents. Stratified analyses and interaction tests were performed by age, gender, and race.

RESULTS

Participants of the higher quartile of copper intake were more likely to be older, men, Non-Hispanic White, and Other Hispanic. They have higher values of poverty income ratio (PIR), serum phosphorus, blood urea nitrogen, serum vitamin D, and BMD and lower values of body mass index (BMI), cholesterol, total protein, and serum cotinine. In the fully adjusted model, we found positive associations between copper intake and total BMD (β = 0.013, 95CI: 0.006, 0.019)), subtotal BMD (β = 0.020, 95CI: 0.015, 0.024), and total spine BMD (β = 0.014, 95CI: 0.009, 0.019). Stratified analyses showed that the association was stronger in men, individuals aged 14-19, Non-Hispanic White, and Other Hispanic.

CONCLUSIONS

Our study suggests that copper intake is positively associated with BMD in U.S. children and adolescents. The study emphasizes the role of copper intake on bone health in the early stages of life. However, more investigations are needed to verify our findings and their underlying mechanisms.

The natural course of bone mineral density in transgender youth before medical treatment; a cross sectional study

OBJECTIVE

Bone mineral density (BMD) Z-scores decrease during puberty suppression in transgender youth. Assessment of treatment impact has been based on the assumption that without intervention, BMD Z-scores remain stable. However, the natural course of BMD in this population is unknown.

DESIGN

Retrospective cross-sectional study.

METHODS

Dual-energy X-ray absorptiometry scans prior to medical intervention were included from 333 individuals assigned male at birth (AMAB) and 556 individuals assigned female at birth (AFAB) aged 12-25 years. The relationship between age and BMD Z-scores of sex assigned at birth was analysed for the lumbar spine (LS), total hip (TH), femoral neck (FN), and total-body-less-head (TBLH), adjusted for height SDS, height-adjusted lean mass Z-score, and whole body percentage fat Z-score.

RESULTS

In individuals AMAB, the BMD Z-score was negatively associated with age between 12 and 22 years: LS -0.13/year (95% confidence interval, CI -0.17; -0.10); TH -0.05/year (95% CI -0.08; -0.02); FN -0.06/year (95% CI -0.10; -0.03); and TBLH -0.12/year (95% CI -0.15; -0.09). Adjusting for height-adjusted lean mass Z-score attenuated the association at the LS and TBLH and eliminated the association at the TH and FN. BMD Z-scores and age were not associated between 22 and 25 years. In individuals AFAB, BMD Z-scores were only associated with age at the TBLH (-0.08/year, 95% CI -0.12; -0.04) between age 12 and 20 years.

CONCLUSION

In individuals AMAB aged 12-22 years prior to any treatment, BMD Z-scores were inversely correlated with age. This could imply that BMD increases less in individuals AMAB than in the general population, and that changes in Z-score during puberty suppression and subsequent hormone supplementation are not necessarily due to treatment, but possibly related to lifestyle factors.

Greater urinary calcium excretion is associated with diminished bone accrual in youth with type 1 diabetes

CONTEXT

The adverse skeletal effects of type 1 diabetes (T1D) include deficient bone accrual and lifelong increased fracture risk. The contributors to impaired bone accrual in people with T1D are incompletely understood.

OBJECTIVE

To determine if urinary calcium excretion is associated with impaired bone accrual in youth with T1D and to characterize the contribution of glycemic control and markers of bone mineral metabolism to urinary calcium excretion.

DESIGN

Observational study.

PARTICIPANTS

50 participants with T1D aged 6-20 years completed a 12-month longitudinal study of bone accrual. A second cohort of 99 similarly aged participants with T1D completed cross-sectional 24-hr urine and blood collections.

MAIN OUTCOME MEASURE

Whole body less head bone mineral content (WBLH BMC) velocity Z-score and fractional excretion of calcium (FeCa).

RESULTS

Participants in the bone accrual cohort had lower WBLH BMC velocity compared to a healthy reference dataset (Z-score -0.3 ± 1.0, p=0.03). FeCa was negatively associated with WBLH BMC velocity Z-score, ρ= -0.47, p=0.001. In the urinary calcium excretion cohort, intact parathyroid hormone (β= -0.4, p=0.01), beta c-telopeptide (β=0.35, p=0.007), and either hemoglobin A1c (HbA1c, β=0.08, p=0.03) or urine fractional glucose excretion (β=0.07, p=0.03) were associated with FeCa in multivariable regression models that included known determinants of urinary calcium excretion.

CONCLUSIONS

Urinary calcium excretion was negatively associated with bone accrual in this cohort of youth with T1D. Mechanistic studies are needed to determine if interventions to reduce urinary calcium excretion could increase bone accrual and reduce skeletal fragility in people with T1D.

Acquisition of peak bone mass in a Norwegian youth cohort: longitudinal findings from the Fit Futures study 2010-2022

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.

Upper and lower limb bone mass accrual in adolescent footballers across a short period of training and competition

OBJECTIVES

To analyze bone mineral content (BMC) and area bone mineral density (aBMD) accrual in adolescent male footballers who started their first football season.

METHODS

17 athletes (14.8 ± 0.4 years) were monitored across 15 weeks of football training. Participants were evaluated for somatic maturation (HPHV), BMC, and aBMD at three time points: before (M1) and after (M2) a preparatory phase, and at the end of the competitive phase (M3). BMC and aBMD were measured using DXA scans. Participants were divided into groups according to maturation status (circa-PHV and post-PHV), and the amount of accumulated training load (median split).

RESULTS

A significant effect (12.1 g/week, standard error (SE) = 2.6 g/week) was observed for lower limbs BMC across the three time points. There were no significant effects of time for upper limbs BMC. There was a significant effect of time for total body aBMD (0.007, SE = 0.003 g/cm2/week) across the three time points. Adolescents at post-PHV had a significant 245.6 g (SE = 56.1 g) higher BMC compared to adolescents at circa-PHV. No significant effects were observed for the accumulated training load.

CONCLUSION

Systematic football training, even during the growth spurt, has a positive impact on adolescent bone markers despite the accumulated training load and maturation.

Associations Between Serum Selenium and Bone Mineral Density in 8-19-year-old children and adolescents: NHANES 2013-2018

The peak bone mass (PBM) in puberty has been proven to be a critical determinant of osteoporosis and brittle fractures in the elderly. Selenium is an essential trace element that could influence bone metabolism in our bodies. However, no study has investigated the impact of selenium status on bone mineral density (BMD) among children and adolescents. This was a cross-section study from National Health and Nutrition Examination Survey (NHANES) in the USA involving participants aged 8-19 years. We conducted multiple linear regression models to assess the relationship between selenium status and BMD among children and adolescents, and then stratified analyses were performed according to genders and races. Smooth curve fits and two-piecewise linear regression models were conducted to explore their nonlinear relationship. A total of 4570 participants (2338 boys and 2232 girls) were included in the present study, with a mean age of 13.57 ± 3.41 years. In the multivariable adjustment model, serum selenium was positively associated with lumbar spine BMD (β = 0.021 95% CI: 0.008, 0.034, P = 0.001). The dose-response analyses indicated a non-linear inverted U-shaped relationship between serum selenium and lumbar spine BMD. Lower and higher selenium concentrations were related to decreased BMD, and the inflection point of serum selenium was 2.60 umol/L. The inverted U-shaped association was also observed in females (inflection point: 2.49 umol/L), males (inflection point: 2.65 umol/L), Non-Hispanic White (inflection point: 2.50 umol/L), Non-Hispanic Black (inflection point: 2.50 umol/L), and other races (Including multi-racial) (inflection point: 2.81 umol/L). Our study first shows a non-linear inversed U-shaped association between selenium status and BMD among children and adolescents. The proper selenium status will benefit bone health in children and adolescents. More research is still required to verify our findings and their potential mechanisms.

Association between hepatitis A seropositivity and bone mineral density in adolescents and adults: a cross-sectional study using NHANES data

BACKGROUND

Osteoporosis, characterized by decreased bone density and increased fracture risk, imposes significant physical, psychosocial, and financial burdens. Early detection and prevention are crucial for managing osteoporosis and reducing the risk of fractures.

OBJECTIVES

To investigate the relationship between Hepatitis A seropositivity and bone mineral density (BMD) in adolescents and adults and to explore the potential link between Hepatitis A infection and osteoporosis risk.

DESIGN AND SETTING

This cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018 to evaluate the association between hepatitis A seropositivity and BMD in 15,693 participants.

METHODS

Multivariable regression analysis was used to calculate the mean BMD and standard error for adolescents and adults, followed by an independent z-test to determine whether there was a significant difference between the seropositive and seronegative groups.

RESULTS

Hepatitis A seropositive adolescents and adults had lower BMD than their seronegative counterparts, with significant differences in lumber spine (mean difference = -0.03 g/cm2, P < 0.01 for both age groups) and pelvis BMDs (mean difference = -0.02 g/cm2, P < 0.01 for the adult age groups), after adjusting for various covariates.

CONCLUSIONS

This study confirmed that both adolescent and adult individuals seropositive for Hepatitis A antibodies had reduced BMD among both adolescents and adults, especially in the adult group. This finding suggests a possible link between Hepatitis A infection and risk of osteoporosis.

Association of coffee intake with bone mineral density: a Mendelian randomization study

Background

In observational studies, the relationship between coffee intake and bone mineral density (BMD) is contradictory. However, residual confounding tends to bias the results of these studies. Therefore, we used a two-sample Mendelian randomization (MR) approach to further investigate the potential causal relationship between the two.

Methods

Genetic instrumental variables (IVs) associated with coffee intake were derived from genome-wide association studies (GWAS) of the Food Frequency Questionnaire (FFQ) in 428,860 British individuals and matched using phenotypes in PhenoScanner. Summarized data on BMD were obtained from 537,750 participants, including total body BMD (TB-BMD), TB-BMD in five age brackets ≥60, 45-60, 30-45, 15-30, and 0-15 years, and BMD in four body sites: the lumbar spine, the femoral neck, the heel, and the ultradistal forearm. We used inverse variance weighting (IVW) methods as the primary analytical method for causal inference. In addition, several sensitivity analyses (MR-Egger, Weighted median, MR-PRESSO, Cochran's Q test, and Leave-one-out test) were used to test the robustness of the results.

Results

After Bonferroni correction, Coffee intake has a potential positive correlation with total body BMD (effect estimate [Beta]: 0.198, 95% confidence interval [Cl]: 0.05-0.35, P=0.008). In subgroup analyses, coffee intake was potentially positively associated with TB-BMD (45-60, 30-45 years) (Beta: 0.408, 95% Cl: 0.12-0.69, P=0.005; Beta: 0.486, 95% Cl: 0.12-0.85, P=0.010). In addition, a significant positive correlation with heel BMD was also observed (Beta: 0.173, 95% Cl: 0.08-0.27, P=0.002). The results of the sensitivity analysis were generally consistent.

Conclusion

The results of the present study provide genetic evidence for the idea that coffee intake is beneficial for bone density. Further studies are needed to reveal the biological mechanisms and offer solid support for clinical guidelines on osteoporosis prevention.

Reference-Class Problems Are Real: Health-Adjusted Reference Classes and Low Bone Mineral Density

Elselijn Kingma argues that Christopher Boorse's biostatistical theory (the BST) does not show how the reference classes it uses are objective and naturalistic. Recently, philosophers of medicine have attempted to rebut Kingma's concerns. I argue that these rebuttals are theoretically unconvincing, and that there are clear examples of physicians adjusting their reference classes according to their prior knowledge of health and disease. I focus on the use of age-adjusted reference classes to diagnose low bone mineral density in children. In addition to using the BST's age, sex, and species, physicians also choose to use other factors to define reference classes, such as pubertal status, bone age, body size, and muscle mass. I show that physicians calibrate the reference classes they use according to their prior knowledge of health and disease. Reference classes are also chosen for pragmatic reasons, such as to predict fragility fractures.

Body Composition Changes in Adolescents Who Underwent Bariatric Surgery: A Systematic Review and Meta-analysis

PURPOSE OF REVIEW

The purpose of this review and meta-analysis is to characterize the changes in body composition of children and adolescents who underwent bariatric surgery and identify possible negative effects of performing this procedure during pediatric ages.

RECENT FINDINGS

Bariatric surgery in children and adolescents is an emerging strategy to promote higher and faster body weight and fat mass losses. However, possible negative effects usually observed in surgical patients' muscle-skeletal system raise a major concern perform this intervention during growth. Despite these possible issues, most experimental studies and reviews analyze bariatric surgery's effectiveness only by assessing anthropometric outcomes such as body weight and BMI, disregarding the short- and long-term impact of bariatric surgery on all body composition outcomes. Bariatric surgery is effective to reduce fat mass in adolescents, as well as body weight, waist circumference, and BMI. Significant reduction in lean mass and fat-free mass is also observed. Bone mass seems not to be impaired. All outcomes reduction were observed only in the first 12 months after surgery. Sensitivity analysis suggests possible sex and type of surgery-related differences, favoring a higher fat mass, body weight, and BMI losses in boys and in patients who underwent RYGB.

Exposure to perfluoroalkyl substances and longitudinal changes in bone mineral density in adolescents and young adults: A multi-cohort study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) may impair bone development in adolescence, which impacts life-long bone health. No previous studies have examined prospective associations of individual PFAS and their mixture with bone mineral density (BMD) changes in Hispanic young persons, a population at high risk of osteoporosis in adulthood.

OBJECTIVES

To examine associations of individual PFAS and PFAS mixtures with longitudinal changes in BMD in an adolescent Hispanic cohort and examine generalizability of findings in a mixed-ethnicity young adult cohort (58.4% Hispanic).

METHODS

Overweight/obese adolescents from the Study of Latino Adolescents at Risk of Type 2 Diabetes (SOLAR; n = 304; mean follow-up = 1.4 years) and young adults from the Southern California Children's Health Study (CHS; n = 137; mean follow-up = 4.1 years) were included in this study. Plasma PFAS were measured at baseline and dual x-ray absorptiometry scans were performed at baseline and follow-up to measure BMD. We estimated longitudinal associations between BMD and five PFAS via separate covariate-adjusted linear mixed effects models, and between BMD and the PFAS mixture via quantile g-computation.

RESULTS

In SOLAR adolescents, baseline plasma perfluorooctanesulfonic acid (PFOS) was associated with longitudinal changes in BMD. Each doubling of PFOS was associated with an average -0.003 g/cm2 difference in change in trunk BMD per year over follow-up (95% CI: -0.005, -0.0002). Associations with PFOS persisted in CHS young adults, where each doubling of plasma PFOS was associated with an average -0.032 g/cm2 difference in total BMD at baseline (95% CI -0.062, -0.003), though longitudinal associations were non-significant. We did not find associations of other PFAS with BMD; associations of the PFAS mixture with BMD outcomes were primarily negative though non-significant.

DISCUSSION

PFOS exposure was associated with lower BMD in adolescence and young adulthood, important periods for bone development, which may have implications on future bone health and risk of osteoporosis in adulthood.

Bone Mineral Density in Transgender Adolescents Treated With Puberty Suppression and Subsequent Gender-Affirming Hormones

Importance

Bone mineral density (BMD) z scores in transgender adolescents decrease during puberty suppression with a gonadotropin-releasing hormone (GnRH) agonist. Previous research found that after short-term use of gender-affirming hormones (GAH), pretreatment z scores were not restored. Long-term follow-up studies are lacking.

Objective

To assess BMD after long-term GAH treatment in transgender adults who used puberty suppression in adolescence.

Design, Setting, and Participants

This single-center cohort study with follow-up duration of 15 years selected participants from a database containing all people visiting a gender identity clinic at an academic hospital in the Netherlands between 1972 and December 31, 2018. Recruitment occurred from March 1, 2020, to August 31, 2021. A total of 75 participants diagnosed with gender dysphoria who had used puberty suppression before age 18 years prior to receiving at least 9 years of long-term GAH were included.

Exposures

Puberty suppression with a GnRH agonist followed by GAH treatment.

Main Outcomes and Measures

Lumbar spine, total hip, and femoral neck BMD and z scores before the start of puberty suppression, at start of GAH, and at short- and long-term follow-up.

Results

Among 75 participants, 25 were assigned male at birth, and 50 were assigned female at birth. At long-term follow-up, the median (IQR) age was 28.2 (27.0-30.8) years in participants assigned male at birth and 28.2 (26.6-30.6) years in participants assigned female at birth. The median (IQR) duration of GAH treatment was 11.6 (10.1-14.7) years among those assigned male at birth and 11.9 (10.2-13.8) years among those assigned female at birth. The z scores decreased during puberty suppression. In individuals assigned male at birth, the mean (SD) z score after long-term GAH use was -1.34 (1.16; change from start of GnRH agonist: -0.87; 95% CI, -1.15 to -0.59) at the lumbar spine, -0.66 (0.75; change from start of GnRH agonist: -0.12; 95% CI, -0.31 to 0.07) at the total hip, and -0.54 (0.84; change from start of GnRH agonist: 0.01; 95% CI, -0.20 to 0.22) at the femoral neck. In individuals assigned female at birth, after long-term GAH use, the mean (SD) z score was 0.20 (1.05; change from start of GnRH agonist: 0.09; 95% CI, -0.09 to 0.27) at the lumbar spine, 0.07 (0.91; change from start of GnRH agonist: 0.10; 95% CI, -0.06 to 0.26) at the total hip, and -0.19 (0.94; change from start of GnRH agonist: -0.20; 95% CI, -0.26 to 0.06) at the femoral neck.

Conclusions and Relevance

In this cohort study, after long-term use of GAH, z scores in individuals treated with puberty suppression caught up with pretreatment levels, except for the lumbar spine in participants assigned male at birth, which might have been due to low estradiol concentrations. These findings suggest that treatment with GnRH agonists followed by long-term GAH is safe with regard to bone health in transgender persons receiving testosterone, but bone health in transgender persons receiving estrogen requires extra attention and further study. Estrogen treatment should be optimized and lifestyle counseling provided to maximize bone development in individuals assigned male at birth.

Analyzing Sex-Specific Dimorphism in Human Skeletal Stem Cells

Sex-related differences are a current topic in contemporary science. In addition to hormonal regulation, cell-autonomous mechanisms are important in bone homeostasis and regeneration. In this study, human skeletal stem cells (SSCs) from female and male adults were cultured and analyzed with immunological assays and osteogenic differentiation assessments. Female SSCs exhibited a mean doubling time of 100.6 h, whereas male SSCs displayed a mean doubling time of 168.0 h. Immunophenotyping revealed the expression of the stem cell markers Nestin, CD133, and CD164, accompanied by the neural-crest marker SOX9. Furthermore, multiparameter flow cytometric analyses revealed a substantial population of multipotent SSCs, comprising up to 80% in both sexes. An analysis of the osteogenic differentiation potential demonstrated a strong mineralization in both male and female SSCs under physiological conditions. Recognizing the prevailing association of bone diseases with inflammatory processes, we also analyzed the osteogenic potential of SSCs from both sexes under pro-inflammatory conditions. Upon TNF-α and IL-1β treatment, we observed no sexual dimorphism on osteogenesis. In summary, we demonstrated the successful isolation and characterization of SSCs capable of rapid osteogenic differentiation. Taken together, in vitro cultured SSCs might be a suitable model to study sexual dimorphisms and develop drugs for degenerative bone diseases.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

Bone is a tissue that is active throughout the lifespan, and its physiological activities, such as growth, development, absorption, and formation, are always ongoing. All types of stimulation that occur in sports play an important role in regulating the physiological activities of bone. Here, we track the latest research progress locally and abroad, summarize the recent, relevant research results, and systematically summarize the effects of different types of exercise on bone mass, bone strength and bone metabolism. We found that different types of exercise have different effects on bone health due to their unique technical characteristics. Oxidative stress is an important mechanism mediating the exercise regulation of bone homeostasis. Excessive high-intensity exercise does not benefit bone health but induces a high level of oxidative stress in the body, which has a negative impact on bone tissue. Regular moderate exercise can improve the body's antioxidant defense ability, inhibit an excessive oxidative stress response, promote the positive balance of bone metabolism, delay age-related bone loss and deterioration of bone microstructures and have a prevention and treatment effect on osteoporosis caused by many factors. Based on the above findings, we provide evidence for the role of exercise in the prevention and treatment of bone diseases. This study provides a systematic basis for clinicians and professionals to reasonably formulate exercise prescriptions and provides exercise guidance for patients and the general public. This study also provides a reference for follow-up research.

Bone Density, Geometry, Structure and Strength Estimates in Adolescent and Young Adult Women with Atypical Anorexia Nervosa versus Typical Anorexia Nervosa and Normal-Weight Healthy Controls

Our objective was to characterize bone outcomes in adolescent and young adult women with atypical anorexia nervosa (AAN) compared to typical AN and normal-weight healthy controls (HC) based on DSM-5 criteria. Four hundred thirty-two participants (141 AN, 131 AAN and 160 HC), ages 12-21 years, underwent dual-energy X-ray absorptiometry for areal BMD, and a subset had high-resolution peripheral quantitative CT assessment of the distal radius and tibia for volumetric BMD (vBMD), bone geometry and microarchitecture, and microfinite element analysis for estimated strength. The groups did not differ for age, pubertal stage, menarcheal age or physical activity. BMI and bone outcomes overall were intermediate in AAN compared with AN and HC. This applied to spine, total hip and femoral neck BMD measures and many distal tibial measures. However, the mean whole-body less head BMD Z-score did not differ between AAN and AN, and it was lower in both vs. HC. Similarly, many distal radius measures did not differ between AAN vs. AN or HC but were lower in AN than HC. Lower BMI, lean mass and bone age, older menarcheal age and longer illness duration correlated with greater impairment of bone outcomes. These data indicate that individuals with AAN overall have bone outcomes that are intermediate between AN and HC.

Yoga as an intervention to promote bone and mental health in adolescent females with anorexia nervosa: a pilot study

In this randomized pilot study, we examined the effects of yoga intervention on axial and peripheral bone mineral density (BMD), disordered eating cognitions, anxiety, and depression in adolescent girls with anorexia nervosa (AN). Fifteen young women aged 13-18 years with AN or atypical AN were randomized to either a Yoga group (n = 7), including twice-weekly yoga for 24 weeks plus standard outpatient care, or Non-Yoga group (n = 8), who received standard outpatient care alone. Data from anthropometrics, mental health and eating behavior questionnaires, dual-energy x-ray absorptiometry, and peripheral quantitative computed tomography measurements were obtained at baseline and 6 months. The adjunct of yoga to standard treatment resulted in statistically significant improvement of axial BMD, depression, and disordered eating cognitions in comparison to the Non-Yoga group. In conclusion, a gentle yoga intervention may be beneficial for improving bone and mental health in adolescent females with AN.

Bone changes post-sleeve gastrectomy in relation to body mass and hormonal changes

OBJECTIVE

To determine mechanisms contributing to impaired bone health in youth 24 months following sleeve gastrectomy (SG).

DESIGN

Twenty-four-month longitudinal observational study.

METHODS

Participants included 23 youth undergoing SG and 30 non-surgical controls (NS) 13-25 years old with moderate-to-severe obesity. Subjects underwent fasting labs for bone turnover markers (N-terminal propeptide of type 1 procollagen, C-telopeptide (CTX)), sex hormones, sex hormone binding globulin (SHBG), and enteric peptides, DXA for areal bone mineral density (aBMD) and body composition, high-resolution peripheral quantitative CT for volumetric BMD (vBMD) at the distal radius and tibia, and microfinite element analysis for strength estimates.

RESULTS

Groups did not differ for mean age or BMI z-scores. Over 24 months, compared to NS, SG had greater reductions in BMI z-scores, and spine, hip, and femoral neck aBMD Z-scores (P ≤ .012), greater increases in serum CTX and SHBG (P ≤ .039), and greater decreases in estrone and ghrelin (P ≤ .021). Among females, estrone and free androgen index (FAI) decreased (P ≤ .022) in SG vs NS groups. After controlling for age and sex, decreases in BMI and lean mass were associated with decreases in total hip and femoral neck aBMD Z-scores, and decreases in radial total and trabecular vBMD and failure load, and tibial total and trabecular vBMD. Among females, after controlling for age, decreases in estrone were associated with decreases in spine aBMD Z-scores and radial total and trabecular vBMD, and decrease in FAI with decreases in radial failure load.

CONCLUSION

Reductions in BMI, lean mass, and sex steroids over 24 months post-SG are associated with bone loss and could be targeted for preventative or therapeutic interventions. Clinical trial registration number: The study is registered in ClinicalTrials.gov (NCT02557438).

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

Introduction

We investigated the effects of hormonal and non-hormonal oral contraceptives (OCs) on bone mass, mineralization, composition, mechanical properties, and metabolites in pubertal female SD rats.

Methods

OCs were given for 3-, and 7 months at human equivalent doses. The combined hormonal contraceptive (CHC) was ethinyl estradiol and progestin, whereas the non-hormonal contraceptive (NHC) was ormeloxifene. MicroCT was used to assess bone microarchitecture and BMD. Bone formation and mineralization were assessed by static and dynamic histomorphometry. The 3-point bending test, nanoindentation, FTIR, and cyclic reference point indentation (cRPI) measured the changes in bone strength and material composition. Bone and serum metabolomes were studied to identify potential biomarkers of drug efficacy and safety and gain insight into the underlying mechanisms of action of the OCs.

Results

NHC increased bone mass in the femur metaphysis after 3 months, but the gain was lost after 7 months. After 7 months, both OCs decreased bone mass and deteriorated trabecular microarchitecture in the femur metaphysis and lumbar spine. Also, both OCs decreased the mineral: matrix ratio and increased the unmineralized matrix after 7 months. After 3 months, the OCs increased carbonate: phosphate and carbonate: amide I ratios, indicating a disordered hydroxyapatite crystal structure susceptible to resorption, but these changes mostly reversed after 7 months, indicating that the early changes contributed to demineralization at the later time. In the femur 3-point bending test, CHC reduced energy storage, resilience, and ultimate stress, indicating increased susceptibility to micro-damage and fracture, while NHC only decreased energy storage. In the cyclic loading test, both OCs decreased creep indentation distance, but CHC increased the average unloading slope, implying decreased microdamage risk and improved deformation resistance by the OCs. Thus, reduced bone mineralization by the OCs appears to affect bone mechanical properties under static loading, but not its cyclic loading ability. When compared to an age-matched control, after 7 months, CHC affected 24 metabolic pathways in bone and 9 in serum, whereas NHC altered 17 in bone and none in serum. 6 metabolites were common between the serum and bone of CHC rats, suggesting their potential as biomarkers of bone health in women taking CHC.

Conclusion

Both OCs have adverse effects on various skeletal parameters, with CHC having a greater negative impact on bone strength.

The dose-dependent effect of estrogen on bone mineral density in trans girls

OBJECTIVE

Treatment in transgender girls can consist of puberty suppression (PS) with a gonadotropin-releasing hormone agonist (GnRHa) followed by gender-affirming hormonal treatment (GAHT) with estrogen. Bone mineral density (BMD) Z-scores decrease during PS and remain relatively low during GAHT, possibly due to insufficient estradiol dosage. Some adolescents receive high-dose estradiol or ethinyl estradiol (EE) to limit growth allowing comparison of BMD outcomes with different dosages.

DESIGN

Retrospective study.

METHODS

Adolescents treated with GnRHa for ≥1 year prior to GAHT followed by treatment with a regular estradiol dose (gradually increased to 2 mg), 6 mg estradiol or 100-200 µg EE were included to evaluate height-adjusted BMD Z-scores (HAZ scores) on DXA.

RESULTS

Eighty-seven adolescents were included. During 2.3 ± 0.7 years PS, lumbar spine HAZ scores decreased by 0.69 [95% confidence interval (CI) -0.82 to -0.56)]. During 2 years HT, lumbar spine HAZ scores hardly increased in the regular group (0.14, 95% CI -0.01 to 0.28, n = 59) vs 0.42 (95% CI 0.13 to 0.72) in the 6 mg group (n = 13), and 0.68 (95% CI 0.20 to 1.15) in the EE group (n = 15). Compared with the regular group, the increase with EE treatment was higher (0.54, 95% CI 0.05 to 1.04). After 2 years HT, HAZ scores approached baseline levels at start of PS in individuals treated with 6 mg or EE (difference in 6 mg group -0.20, 95% CI -0.50 to 0.09; in EE 0.17, 95% CI -0.16 to 0.50) but not in the regular group (-0.64, 95% CI -0.79 to -0.49).

CONCLUSION

Higher estrogen dosage is associated with a greater increase in lumbar spine BMD Z-scores. Increasing dosage up to 2 mg estradiol is insufficient to optimize BMD and approximately 4 mg may be required for adequate serum concentrations.

Tarsal Navicular Bone Stress Injuries: A Multicenter Case Series Investigating Clinical Presentation, Diagnostic Approach, Treatment, and Return to Sport in Adolescent Athletes

BACKGROUND

Tarsal navicular bone stress injuries (BSIs) are considered "high risk" because of prolonged healing times and higher rates of nonunion in adult populations but, to our knowledge, have not been comprehensively examined in adolescent athletes.

PURPOSE

To describe the characteristics of tarsal navicular BSIs in adolescents.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective analysis of patients aged 10 to 19 years with a radiographically diagnosed tarsal navicular BSI was performed at 8 academic centers over a 9-year study period. Age, sex, body mass index (BMI), primary sport, physical examination findings, imaging, treatment, surgical technique, return-to-sport time, and complications were analyzed.

RESULTS

Among 110 patients (mean age, 14.7 ± 2.7 years; 65% female), common primary sports were cross-country/track and field (29/92 [32%]) and gymnastics/dance (25/92 [27%]). Grade 4 BSIs were identified in 44% (48/110) of patients, with fracture lines present on radiography or magnetic resonance imaging. Nonoperative treatment (mean age, 14.4 ± 2.6 years), consisting of protected weightbearing and either a protective boot (69/88 [78%]) or a cast (19/88 [22%]), was trialed in all patients and was successful in 94 patients (85%). Operative treatment (mean age, 17.1 ± 1.4 years) was ultimately pursued for 16 patients (15%). Patients who required surgery had a higher BMI and a higher percentage of fracture lines present on imaging (nonoperative: 36/94 [38%]; operative: 14/16 [88%]). The median time to return to weightbearing, running, and full sport was significantly longer in duration for the operative group than the nonoperative group (P <.05). Complications associated with surgery included 1 case each of delayed union, nonunion, and painful implants, the latter of which required secondary surgery.

CONCLUSION

Adolescent tarsal navicular BSIs were identified most commonly in female patients in leanness sports. Adolescents who required surgery were more likely to be older, have higher BMIs, and have grade 4 BSIs, and they returned to sport within a median of 5 months after single- or double-screw fixation with a low risk of postoperative complications. A better understanding of the presenting signs and symptoms and appropriate diagnostic imaging of navicular BSIs may lead to an earlier diagnosis and improved outcomes.

Biomechanical CT to Assess Bone After Sleeve Gastrectomy in Adolescents With Obesity: A Prospective Longitudinal Study

Sleeve gastrectomy (SG) is effective in treating cardiometabolic complications of obesity but is associated with bone loss. Our aim was to determine the effect of SG on the lumbar spine by biomechanical CT analysis in adolescents/young adults with obesity. We hypothesized that SG would lead to a decrease in strength and bone mineral density (BMD) compared with nonsurgical controls. In a 12-month prospective nonrandomized study, adolescents/young adults with obesity underwent SG (n = 29, 18.0 ± 2.1 years, 23 female) or were followed without surgery (controls, n = 30, 17.95 ± 3.0 years, 22 female). At baseline and 12 months, participants underwent quantitative computed tomography (QCT) of L1 and L2 for biomechanical assessment and MRI of the abdomen and mid-thigh for body composition assessment. Twelve-month changes between groups and within groups were assessed. Analyses were controlled for baseline and 12-month changes in body mass index (BMI) by multivariable analyses. Regression analysis was performed to evaluate the effect of body composition on bone parameters. Our institutional review board (IRB) approved the study, and informed consent/assent was obtained. Participants in the SG group had a higher baseline BMI than controls (p = 0.01) and lost an average of 34.3 ± 13.6 kg 12 months after surgery, whereas weight was unchanged in controls (p < 0.001). There were significant reductions in abdominal adipose tissue and thigh muscle area in the SG group compared with controls (p < 0.001). Bone strength, bending stiffness, and average and trabecular volumetric BMD decreased in the SG group compared with controls (p < 0.001). After controlling for change in BMI, a 12-month reduction in cortical BMD was significant in the SG group compared with controls (p = 0.02). Reductions in strength and trabecular BMD were associated with reductions in BMI, visceral adipose tissue, and muscle (p ≤ 0.03). In conclusion, SG in adolescents decreased strength and volumetric BMD of the lumbar spine compared with nonsurgical controls. These changes were associated with decreases in visceral fat and muscle mass. © 2023 American Society for Bone and Mineral Research (ASBMR).

Two-year Skeletal Effects of Sleeve Gastrectomy in Adolescents with Obesity Assessed with Quantitative CT and MR Spectroscopy

Background Sleeve gastrectomy (SG) is effective in the treatment of cardiometabolic complications of obesity but is associated with bone loss. Purpose To determine the long-term effects of SG on vertebral bone strength, density, and bone marrow adipose tissue (BMAT) in adolescents and young adults with obesity. Materials and Methods This 2-year prospective nonrandomized longitudinal study enrolled adolescents and young adults with obesity who underwent either SG (SG group) or dietary and exercise counseling without surgery (control group) at an academic medical center from 2015 to 2020. Participants underwent quantitative CT of the lumbar spine (L1 and L2 levels) to assess bone density and strength, proton MR spectroscopy to assess BMAT (L1 and L2 levels), and MRI of the abdomen and thigh to assess body composition. Student t and Wilcoxon signed-rank tests were used to compare 24-month changes between and within groups. Regression analysis was performed to evaluate associations between body composition, vertebral bone density, strength, and BMAT. Results A total of 25 participants underwent SG (mean age, 18 years ± 2 [SD], 20 female), and 29 underwent dietary and exercise counseling without surgery (mean age, 18 years ± 3, 21 female). Body mass index (BMI) decreased by a mean of 11.9 kg/m2 ± 5.21 [SD] after 24 months in the SG group (P < .001), while it increased in the control group (mean increase, 1.49 kg/m2 ± 3.10; P = .02). Mean bone strength of the lumbar spine decreased after surgery compared with that in control subjects (mean decrease, -728 N ± 691 vs -7.24 N ± 775; P < .001). BMAT of the lumbar spine increased after SG (mean lipid-to-water ratio increase, 0.10 ± 0.13; P = .001). Changes in vertebral density and strength correlated positively with changes in BMI and body composition (R = 0.34 to R = 0.65, P = .02 to P < .001) and inversely with vertebral BMAT (R = -0.33 to R = -0.47, P = .03 to P = .001). Conclusion SG in adolescents and young adults reduced vertebral bone strength and density and increased BMAT compared with those in control participants. Clinical trial registration no. NCT02557438 © RSNA, 2023 See also the editorial by Link and Schafer in this issue.

Associations of urinary metabolite concentrations of phthalates and phthalate replacements with body composition from mid-childhood to early adolescence

BACKGROUND

Phthalates may adversely influence body composition by lowering anabolic hormones and activating peroxisome-proliferator activated receptor gamma. However, data are limited in adolescence when body mass distributions rapidly change and bone accrual peaks. Also, potential health effects of certain phthalate/replacements [e.g., di-2-ethylhexyl terephthalate (DEHTP)] have not been well studied.

METHODS

Among 579 children in the Project Viva cohort, we used linear regression to evaluate associations of urinary concentrations of 19 phthalate/replacement metabolites from mid-childhood (median: 7.6 years; 2007-2010) with annualized change in areal bone mineral density (aBMD) and lean, total fat, and truncal fat mass as measured by dual-energy X-ray absorptiometry between mid-childhood and early adolescence (median: 12.8 years). We used quantile g-computation to assess associations of the overall chemical mixture with body composition. We adjusted for sociodemographics and tested for sex-specific associations.

RESULTS

Urinary concentrations were highest for mono-2-ethyl-5-carboxypentyl phthalate [median (IQR): 46.7 (69.1) ng/mL]. We detected metabolites of most replacement phthalates in a relatively small number of participants [e.g., 28% for mono-2-ethyl-5-hydrohexyl terephthalate (MEHHTP; metabolite of DEHTP)]. Detectable (vs. non-detectable) MEHHTP was associated with less bone and greater fat accrual in males and greater bone and lean mass accrual in females [e.g., change in aBMD Z-score/year (95% CI): -0.049 (-0.085, -0.013) in males versus 0.042 (0.007, 0.076) in females; pinteraction<0.01]. Children with higher concentrations of mono-oxo-isononyl phthalate and mono-3-carboxypropyl phthalate (MCPP) had greater bone accrual. Males with higher concentrations of MCPP and mono-carboxynonyl phthalate had greater accrual of lean mass. Other phthalate/replacement biomarkers, and their mixtures, were not associated with longitudinal changes in body composition.

CONCLUSIONS

Concentrations of select phthalate/replacement metabolites in mid-childhood were associated with changes in body composition through early adolescence. As use of phthalate replacements such as DEHTP may be increasing, further investigation can help better understand the potential effects of early-life exposures.

Interrelationship between muscle fitness in childhood and bone mineral density in adulthood: mediation analysis of muscle fitness in adulthood

BACKGROUND

This study was aimed to examine the relationship between muscular fitness indicators in childhood and areal bone mineral density (aBMD) in adulthood and to verify whether the relationship is mediated by performance on muscular fitness indicators in adulthood.

METHODS

A sample of 138 healthy adults (69 males; 22.3 years) were followed after a previous assessment at the age of 7-10 years. Stature, body mass and muscular fitness indicators (handgrip strength, standing long jump and sit-ups tests) were assessed in childhood and adulthood. Additionally, total body, upper limbs, lower limbs, right femoral neck and lumbar spine aBMD was assessed in adulthood using dual X-ray absorptiometry. Analysis included descriptive statistics; t-test or Mann-Whitney U-test for comparison between males and females, multiple linear regression for the prediction aBMD from muscular fitness indicators in childhood, mediation analysis of the respective muscular fitness indicators in adulthood and the relationship between muscular fitness indicators in childhood and aBMD.

RESULTS

Males were stronger compared to females regarding muscular fitness indicators in childhood and adulthood, and presented higher mean values for aBMD in adulthood, except for lumbar spine (p < 0.05). Regression analysis revealed that some muscular fitness indicators in childhood showed significant positive relationship with bone health indicators in adulthood, such as: handgrip strength and total body aBMD (β = 0.005; R² = 0.35; p = 0.040) and upper limbs aBMD (β = 0.005; R² = 0.55; p = 0.019); and sit-ups test was a significant predictors of lumbar spine BMD (β = 0.003; R² = 0.06; p = 0.039). Mediation analysis pointed out the following: adulthood handgrip strength mediated relationships between childhood handgrip strength and total aBMD (indirect effect (IE) = 0.0025; 95%CI = 0.0005-0.0048), and upper limbs aBMD (IE = 0.0040; 95%CI = 0.0017-0.0069).

CONCLUSIONS

Muscular fitness indicators in childhood showed significant relationship with bone health indicators in adulthood and the sit-ups test in childhood had direct effect on lumbar spine aBMD in adulthood. Adulthood handgrip strength mediated the relationship between childhood handgrip strength and total body and upper limb aBMD, pointing out that muscular fitness in childhood may be a aBMD determinant in adulthood, especially when higher muscle fitness performance is maintained in adulthood.

Association of total body fat and fat distribution with bone mineral density among children and adolescents aged 6-17 years from Guangzhou, China

This study aimed to assess the associations of total body fat and fat distribution with bone mineral density (BMD) among children and adolescents in this cross-sectional study. A total of 1032 boys and 897 girls aged 6-17 years were enrolled between May 2019 and June 2019 in Guangzhou, China. BMD, total body fat (fat mass index [FMI] and body fat percentage [BF%]), and fat distribution (trunk-to-limb and android-to-gynoid ratios) were measured by dual-energy X-ray absorptiometry. Inverse probability of treatment weighting regression was used to explore the association between fat and BMD. Traditional regression of covariate adjustment was applied as sensitivity analysis. Regression with inverse probability weighting suggested BF% and android-to-gynoid ratio were negatively associated with BMD in boys (β =  - 0.12 and - 0.16, respectively; P < 0.05). Android-to-gynoid ratio was also inversely associated with BMD in girls (β =  - 0.08, P < 0.05). When stratified by age, the negative associations were retained in boys aged 12-17 years (β =  - 0.23 and - 0.25, respectively; P < 0.001). But for girls, it showed a positive association of FMI with BMD in the 6-9 years group (β = 0.33, P < 0.001) and a negative association between the android-to-gynoid ratio and BMD in the 10-17 years group (β =  - 0.10, P < 0.05). Traditional regression supported the robustness of the results.  Conclusion: Total body fat is positively associated with BMD in younger girls but inversely associated in older boys. As for abdominal adipose, it is associated with lower BMD in both older boys and girls. What is Known: • The lean mass has been consistently positively associated with bone mineral density (BMD) among children and adolescents. However, the impact of fat mass on BMD remained controversial. • Beyond total body fat, site-specific fat mass, especially abdominal adiposity, might impede bone formation. What is New: • The associations of total body fat and fat distribution with BMD in children and adolescents were gender- and age-specific. • More attention should be paid to the abdominal fat accumulation to promote bone health in older children.

Trabecular Bone Score (TBS) Varies with Correction for Tissue Thickness Versus Body Mass Index: Implications When Using Pediatric Reference Norms

Trabecular bone score (TBS) derived from secondary analysis of lumbar spine dual-energy X-ray absorptiometry (DXA) scans improves fracture prediction independent of bone mineral density (BMD) in adults. The utility of TBS to assess fracture risk in younger patients has not been established because pediatric norms have been lacking. Robust TBS reference data from the Bone Mineral Density in Childhood Study (BMDCS) have been published. TBS values for the BMDCS study were derived using an algorithm that accounts for tissue thickness (TBS_TH ) rather than the commercially available algorithm that adjusts for body mass index (BMI; TBS_BMI ). We examined the magnitude of differences in TBS_TH and TBS_BMI in a cohort of 189 healthy youth. TBS values using both algorithms increased with age and pubertal development in a similar pattern. However, TBS_BMI values were systematically and significantly higher than TBS_TH (mean = 0.06, p < 0.0001). The difference between calculated TBS_BMI and TBS_TH was not uniform. Differences were greater at lower TBS values, in males, in older individuals, in those at later Tanner stages, and in those with a greater BMI Z-score. These systematic differences preclude the development of a simple formula to allow conversion of TBS_BMI to TBS_TH "equivalents." Because of these systematic differences in these two algorithms, using an individual's TBS_BMI to calculate a Z-score using the BMDCS TBS_TH reference values results in a falsely higher TBS Z-score (differences mean = 0.73, interquartile range [IQR] = 0.3 to 1.6). Until TBS_TH software for Hologic DXA equipment becomes commercially available, BMDCS TBS reference norms should not be used. © 2023 American Society for Bone and Mineral Research (ASBMR).

Bone resorption and incretin hormones following glucose ingestion in healthy emerging adults

Background

Studies in adults indicate that macronutrient ingestion yields an acute anti-resorptive effect on bone, reflected by decreases in C-terminal telopeptide (CTX), a biomarker of bone resorption, and that gut-derived incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), facilitate this response. There remain knowledge gaps relating to other biomarkers of bone turnover, and whether gut-bone cross-talk is operative during the years surrounding peak bone strength attainment. This study first, describes changes in bone resorption during oral glucose tolerance testing (OGTT), and second, tests relationships between changes in incretins and bone biomarkers during OGTT and bone micro-structure.

Methods

We conducted a cross-sectional study in 10 healthy emerging adults ages 18-25 years. During a multi-sample 2-hour 75 g OGTT, glucose, insulin, GIP, GLP-1, CTX, bone-specific alkaline phosphatase (BSAP), osteocalcin, osteoprotegerin (OPG), receptor activator of nuclear factor kappa-β ligand (RANKL), sclerostin, and parathyroid hormone (PTH) were assayed at mins 0, 30, 60, and 120. Incremental areas under the curve (iAUC) were computed from mins 0-30 and mins 0-120. Tibia bone micro-structure was assessed using second generation high resolution peripheral quantitative computed tomography.

Results

During OGTT, glucose, insulin, GIP, and GLP-1 increased significantly. CTX at min 30, 60, and 120 was significantly lower than min 0, with a maximum decrease of about 53 % by min 120. Glucose-iAUC_0-30 inversely correlated with CTX-iAUC_0-120 (rho = -0.91, P < 0.001), and GLP-1-iAUC_0-30 positively correlated with BSAP-iAUC_0-120 (rho = 0.83, P = 0.005), RANKL-iAUC_0-120 (rho = 0.86, P = 0.007), and cortical volumetric bone mineral density (rho = 0.93, P < 0.001).

Conclusions

Glucose ingestion yields an anti-resorptive effect on bone metabolism during the years surrounding peak bone strength. Cross-talk between the gut and bone during this pivotal life stage requires further attention.

Twelve weeks of a diet and exercise intervention alters the acute bone response to exercise in adolescent females with overweight/obesity

Introduction: Exercise and consumption of dairy foods have been shown to improve bone mineralization. However, little is known about the magnitude and timing of their synergistic effects on markers and regulators of bone metabolism in response to acute exercise in adolescent females with obesity, a population susceptible to altered bone metabolism and mineral properties. This study examined the influence of twelve weeks of exercise training and nutritional counselling on the bone biochemical marker response to acute exercise and whether higher dairy consumption could further influence the response. Methods: Thirty adolescent females (14.3 ± 2.0 years) with overweight/obesity (OW/OB) completed a 12-week lifestyle modification intervention involving exercise training and nutritional counselling. Participants were randomized into two groups: higher dairy intake (RDa; 4 servings/day; n = 14) or low dairy intake (LDa; 0-2 servings/d; n = 16). Participants performed one bout of plyometric exercise (5 circuits; 120 jumps) both pre- and post-intervention. Blood samples were taken at rest, 5 min and 1 h post-exercise. Serum sclerostin, osteocalcin (OC), osteoprotegerin (OPG), receptor activator nuclear factor kappa B ligand (RANKL), and C-terminal telopeptide of type 1 collagen (βCTX) concentrations were measured. Results: While there was an overall increase in sclerostin pre-intervention from pre to 5 min post-exercise (+11% p = 0.04), this response was significantly decreased post-intervention (-25%, p = 0.03) independent of dairy intake. The OPG:RANKL ratio was unresponsive to acute exercise pre-intervention but increased 1 h post-exercise (+2.6 AU; p < 0.001) post-intervention. Dairy intake did not further influence these absolute responses. However, after the 12-week intervention, the RDa group showed a decrease in the relative RANKL post-exercise response (-21.9%; p < 0.01), leading to a consistent increase in the relative OPG:RANKL ratio response, which was not the case in the LDa group. There was no influence of the intervention or dairy product intake on OC, OPG, or βCTX responses to acute exercise (p > 0.05). Conclusion: A lifestyle modification intervention involving exercise training blunts the increase in sclerostin and can augment the increase in OPG:RANKL ratio to acute exercise in adolescent females with OW/OB, while dairy product consumption did not further influence these responses.

Bone metabolism and incretin hormones following glucose ingestion in young adults with pancreatic insufficient cystic fibrosis

Background

Gut-derived incretin hormones, including glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1), regulate post-prandial glucose metabolism by promoting insulin production. GIP, GLP-1, and insulin contribute to the acute bone anti-resorptive effect of macronutrient ingestion by modifying bone turnover. Cystic fibrosis (CF) is associated with exocrine pancreatic insufficiency (PI), which perturbs the incretin response. Cross-talk between the gut and bone ("gut-bone axis") has not yet been studied in PI-CF. The objectives of this study were to assess changes in biomarkers of bone metabolism during oral glucose tolerance testing (OGTT) and to test associations between incretins and biomarkers of bone metabolism in individuals with PI-CF.

Methods

We performed a secondary analysis of previously acquired blood specimens from multi-sample OGTT from individuals with PI-CF ages 14-30 years (n = 23). Changes in insulin, incretins, and biomarkers of bone resorption (C-terminal telopeptide of type 1 collagen [CTX]) and formation (procollagen type I N-terminal propeptide [P1NP]) during OGTT were computed.

Results

CTX decreased by 32% by min 120 of OGTT (P < 0.001), but P1NP was unchanged. Increases in GIP from 0 to 30 mins (rho = -0.48, P = 0.03) and decreases in GIP from 30 to 120 mins (rho = 0.62, P = 0.002) correlated with decreases in CTX from mins 0-120. Changes in GLP-1 and insulin were not correlated with changes in CTX, and changes in incretins and insulin were not correlated with changes in P1NP.

Conclusions

Intact GIP response was correlated with the bone anti-resorptive effect of glucose ingestion, represented by a decrease in CTX. Since incretin hormones might contribute to development of diabetes and bone disease in CF, the "gut-bone axis" warrants further attention in CF during the years surrounding peak bone mass attainment.

Bone Tissue Responsiveness To Mechanical Loading-Possible Long-Term Implications of Swimming on Bone Health and Bone Development

PURPOSE OF REVIEW

To revisit the bone tissue mechanotransduction mechanisms behind the bone tissue response to mechanical loading and, within this context, explore the possible negative influence of regular swimming practice on bone health, particularly during the growth and development period.

RECENT FINDINGS

Bone is a dynamic tissue, responsive to mechanical loading and unloading, being these adaptative responses more intense during the growth and development period. Cross-sectional studies usually report a lower bone mass in swimmers compared to athletes engaged in weigh-bearing sports. However, studies with animal models show contradictory findings about the effect of swimming on bone health, highlighting the need for longitudinal studies. Due to its microgravity characteristics, swimming seems to impair bone mass, but mostly at the lower limbs. It is unkown if there is a causal relationship between swimming and low BMD or if other confounding factors, such as a natural selection whithin the sport, are the cause.

Bone mass density following developmental exposures to perfluoroalkyl substances (PFAS): a longitudinal cohort study

BACKGROUND

Environmental exposures to industrial chemicals, including perfluoroalkyl substances (PFAS), may play a role in bone development and future risk of osteoporosis. However, as prospective evidence is limited, the role of developmental PFAS exposures in bone density changes in childhood is unclear. The objective of this study was to estimate associations between serum-PFAS concentrations measured in infancy and early childhood and areal bone mineral density (aBMD) measured at age 9 years in a birth cohort of children from the Faroe Islands.

METHODS

We prospectively measured concentrations of five PFAS in cord serum and serum collected at 18 months, 5 years and 9 years, and conducted whole-body DXA scans at the 9-year clinical visit. Our study included 366 mother-child pairs with DXA scans and at least one PFAS measurement. We estimated covariate-adjusted associations of individual PFAS concentrations with age-, sex- and height-adjusted aBMD z-scores using multivariable regression models and applied formal mediation analysis to estimate the possible impact of by several measures of body composition. We also evaluated whether associations were modified by child sex.

RESULTS

We found PFAS exposures in childhood to be negatively associated with aBMD z-scores, with the strongest association seen for perfluorononanoic acid (PFNA) at age 5 years. A doubling in age-5 PFNA was associated with a 0.15 decrease in aBMD z-score (95% CI: - 0.26, - 0.039). The PFNA-aBMD association was significantly stronger in males than females, although effect modification by sex was not significant for other PFAS exposures. Results from the mediation analysis suggested that any potential associations between aBMD and 18-month PFAS concentrations may be mediated by total body fat and BMI, although most estimated total effects for PFAS exposures at age 18 months were non-significant. PFAS exposures at age 9 were not associated with age-9 aBMD z-scores.

CONCLUSIONS

The PFAS-aBMD associations identified in this and previous studies suggest that bone may be a target tissue for PFAS. Pediatric bone density has been demonstrated to strongly track through young adulthood and possibly beyond; therefore, these prospective results may have important public health implications.

Cow's milk-induced gastrointestinal disorders: From infancy to adulthood

Milk is related to many gastrointestinal disorders from the cradle to the grave due to the many milk ingredients that can trigger gastrointestinal discomfort and disorders. Cow's milk protein allergy (CMPA) is the most common food allergy, especially in infancy and childhood, which may persist into adulthood. There are three main types of CMPA; immunoglobulin E (IgE)-mediated CMPA, non-IgE-mediated CMPA, and mixed type. CMPA appears before the first birthday in almost all cases. Symptoms may start even during the neonatal period and can be severe enough to simulate neonatal sepsis. CMPA (often non-IgE mediated) can present with symptoms of gastroesophageal reflux, eosinophilic esophagitis, hemorrhagic gastritis, food protein-induced protein-losing enteropathy, and food protein-induced enterocolitis syndrome. Most CMPAs are benign and outgrown during childhood. CMPA is not as common in adults as in children, but when present, it is usually severe with a protracted course. Lactose intolerance is a prevalent condition characterized by the development of many symptoms related to the consumption of foods containing lactose. Lactose intolerance has four typical types: Developmental, congenital, primary, and secondary. Lactose intolerance and CMPA may be the underlying pathophysiologic mechanisms for many functional gastrointestinal disorders in children and adults. They are also common in inflammatory bowel diseases. Milk consumption may have preventive or promoter effects on cancer development. Milk may also become a source of microbial infection in humans, causing a wide array of diseases, and may help increase the prevalence of antimicrobial resistance. This editorial summarizes the common milk-related disorders and their symptoms from childhood to adulthood.

Female bone physiology resilience in a past Polynesian Outlier community

Remodelling is a fundamental biological process involved in the maintenance of bone physiology and function. We know that a range of health and lifestyle factors can impact this process in living and past societies, but there is a notable gap in bone remodelling data for populations from the Pacific Islands. We conducted the first examination of femoral cortical histology in 69 individuals from ca. 440-150 BP Taumako in Solomon Islands, a remote 'Polynesian Outlier' island in Melanesia. We tested whether bone remodelling indicators differed between age groups, and biological sex validated using ancient DNA. Bone vascular canal and osteon size, vascular porosity, and localised osteon densities, corrected by femoral robusticity indices were examined. Females had statistically significantly higher vascular porosities when compared to males, but osteon densities and ratios of canal-osteon (~ 8%) did not differ between the sexes. Our results indicate that, compared to males, localised femoral bone tissue of the Taumako females did not drastically decline with age, contrary to what is often observed in modern populations. However, our results match findings in other archaeological samples-a testament to past female bone physiology resilience, also now observed in the Pacific region.

Acyloxyacyl hydrolase deficiency induces chronic inflammation and bone loss in male mice

Hormonal homeostasis is essential in bone remodeling. Recent studies have shown that the treatment of intestinal inflammation can result in the regulation of bone resorption in distant bones. Increased intestinal permeability may lead to systemic inflammation and bone loss, also known as gut-bone axis. However, the underlying mechanism remains to be elucidated. Lipopolysaccharide (LPS) is a component of gram-negative bacteria that can increase osteoclastic differentiation in vitro. Acyloxyacyl hydrolase (AOAH) is a specific degrading enzyme of LPS, but little is known about the role of AOAH in bone metabolism. In this study, adult Aoah^-/- mice showed a chronic inflammatory state and osteopenic phenotype analyzed by micro-CT and HE staining. Tartrate-resistant acid phosphatase (TRAP) staining of femurs showed an increase in TRAP-positive cells from Aoah^-/- mice. AOAH depletion enhanced the osteoclast differentiation and bone resorption capacity of bone marrow-derived macrophages (BMMs). The enhanced osteoclast differentiation and bone resorption capacity of Aoah^-/- BMMs were reversed by rAOAH. In conclusion, the chronic inflammatory state of adult Aoah^-/- mice promotes bone resorption. AOAH participates in bone metabolism, which is mainly mediated by inhibiting osteoclast differentiation. LPS may be a key mediator of the gut-bone axis, and targeting AOAH may represent a feasible strategy for the treatment of chronic inflammatory bone resorption. KEY MESSAGES : AOAH knockout mice exhibited chronic inflammation mediated by LPS, and LPS may also serve as an important mediator in the regulation of bone metabolism in the gut-bone axis. AOAH regulated bone resorption by blocking the osteoclast differentiation via classical ERK and JNK pathways. rAOAH could rescue the enhanced osteoclast differentiation caused by AOAH deficiency.

Prenatal and early postnatal exposure to perfluoroalkyl substances and bone mineral content and density in the Odense child cohort

INTRODUCTION

Exposure to perfluoroalkyl substances (PFAS) has been associated with lower bone mineral density (BMD) in animal and human studies, but prospective data from children are limited.

OBJECTIVES

To determine associations between prenatal and early postnatal PFAS exposure and BMD at age 7 years.

METHODS

In the Odense Child Cohort, Denmark, pregnant women were recruited in 2010-2012, and their children were invited for subsequent health examinations. At 12 weeks of gestation the pregnant women delivered a serum sample, and at age 18 months serum was obtained from the child to measure perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) by LC-MS/MS. At age 7 years DXA scans were performed to measure bone mineral content (BMC) and BMD Z-score. PFAS in pregnancy (n = 924) and/or at age 18 months (n = 511) were regressed against DXA measurements, adjusted for maternal education, child height Z-score, sex (for BMC) and for postnatal exposure, additionally duration of total breastfeeding. We additionally performed structural equation models determining combined effects of pre-and postnatal PFAS exposures.

RESULTS

Higher prenatal and early postnatal serum concentrations of all measured PFAS were associated with lower BMC and BMD Z-scores at age 7 years, all estimates were negative although not all significant. For each doubling of prenatal or 18-month exposure to PFDA, BMD Z-scores were lowered by -0.07 (95 % CI -0.10; -0.03) and -0.14 (-0.25; -0.03), respectively after adjustment. Pre- and postnatal PFAS were correlated, but structural equation models suggested that associations with BMD were stronger for 18-month than prenatal PFAS exposure.

DISCUSSION

Bone density is established in childhood, and a reduction in BMD during early childhood may have long-term implication for peak bone mass and lifelong bone health. Future studies of the impact of PFAS exposure on fracture incidence will help elucidate the clinical relevance.

Bone density and bone marrow composition in transgender girls prior to pubertal blockade: A case series

PURPOSE

To determine bone mineral density (BMD) of transgender girls before pubertal blockade, and correlate with lifestyle and clinical variables.

METHODS

Six transfemale peri-pubertal girls had knee magnetic resonance imaging (MRI) with T1-weighted images and single-voxel proton magnetic resonance spectroscopy (MRS). BMD measurements were obtained via dual-energy X-ray absorptiometry. Questionnaires about physical activity, diet, and the Eating Attitudes Test (EAT-26) were completed. The T2 relaxation rate of water (R2 = 1/T2 in s -1) was correlated with scores on surveys.

RESULTS

Three participants (50 %) had a low bone mineral density for age based on total body less head Z-score less than -2; two participants (33 %) had a low BMD for age at lumbar spine. All had EAT-26 scores below threshold for clinical concern. All participants self-reported regular exercise. Bone marrow MR variables (T1, fat fraction, unsaturation index and R2 of water) were not correlated with DXA measures.

CONCLUSIONS

Participants had low BMD on beginning pubertal blockade. Clinicians should consider monitoring BMD among youth AMAB, a group at potential risk for poor bone health.

Adiposity, Insulin Resistance, Cardiorespiratory Fitness, and Bone Health in Hispanic Children

CONTEXT

Childhood obesity disproportionately affects Hispanic youth. The skeletal system appears to be a target organ of the adverse effects of obesity. Yet, the relationship between adiposity and bone health in youth and the modulating factors are not well understood.

OBJECTIVE

This work aims to examine the relationship between adiposity, insulin resistance (IR), cardiorespiratory fitness (CRF), and bone mass in Hispanic youth.

METHODS

A total of 951 Hispanic youth (50% male), aged 4 to 19 years, participated in this cross-sectional design study from the Viva La Familia Study at Children's Nutrition Research Center. Bone mineral content (BMC) and density (BMD), lean mass (LM), total body fat mass (FM), truncal FM were obtained using dual-energy x-ray absorptiometry. Fasting glucose and insulin were obtained and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. CRF was measured using a treadmill ramp protocol. We applied linear regression models and mediation analyses.

RESULTS

Adiposity measures were negatively related to BMC and BMD after accounting for LM and sex. IR negatively contributed whereas CRF positively contributed to the variance in BMC and BMD, more notably in the pubertal age group. In mediation analysis, HOMA-IR partially mediated the negative relationship of adiposity to BMC (standardized indirect effect [IE] = -0.0382; 95% CI, -0.0515 to -0.0264) whereas the sequential IE of HOMA-IR and CRF partially attenuated (IE = -0.0026; 95% CI, -0.0053 to -0.0005) this relationship. Similar findings were seen with BMD as the primary outcome.

CONCLUSION

IR mediates the negative relationship between adiposity and bone mass whereas CRF may partially attenuate it.