Adrenarche and bone modeling and remodeling at the proximal radius: weak androgens make stronger cortical bone in healthy children

Update on Adrenarche-Still a Mystery

CONTEXT

Adrenarche marks the timepoint of human adrenal development when the cortex starts secreting androgens in increasing amounts, in healthy children at age 8-9 years, with premature adrenarche (PA) earlier. Because the molecular regulation and significance of adrenarche are unknown, this prepubertal event is characterized descriptively, and PA is a diagnosis by exclusion with unclear long-term consequences.

EVIDENCE ACQUISITION

We searched the literature of the past 5 years, including original articles, reviews, and meta-analyses from PubMed, ScienceDirect, Web of Science, Embase, and Scopus, using search terms adrenarche, pubarche, DHEAS, steroidogenesis, adrenal, and zona reticularis.

EVIDENCE SYNTHESIS

Numerous studies addressed different topics of adrenarche and PA. Although basic studies on human adrenal development, zonation, and zona reticularis function enhanced our knowledge, the exact mechanism leading to adrenarche remains unsolved. Many regulators seem involved. A promising marker of adrenarche (11-ketotestosterone) was found in the 11-oxy androgen pathway. By current definition, the prevalence of PA can be as high as 9% to 23% in girls and 2% to 10% in boys, but only a subset of these children might face related adverse health outcomes.

CONCLUSION

New criteria for defining adrenarche and PA are needed to identify children at risk for later disease and to spare children with a normal variation. Further research is therefore required to understand adrenarche. Prospective, long-term studies should characterize prenatal or early postnatal developmental pathways that modulate trajectories of birth size, early postnatal growth, childhood overweight/obesity, adrenarche and puberty onset, and lead to abnormal sexual maturation, fertility, and other adverse outcomes.

Hormone-Related and Drug-Induced Osteoporosis: A Cellular and Molecular Overview

Osteoporosis resulting from an imbalance of bone turnover between resorption and formation is a critical health issue worldwide. Estrogen deficiency following a nature aging process is the leading cause of hormone-related osteoporosis for postmenopausal women, while glucocorticoid-induced osteoporosis remains the most common in drug-induced osteoporosis. Other medications and medical conditions related to secondary osteoporosis include proton pump inhibitors, hypogonadism, selective serotonin receptor inhibitors, chemotherapies, and medroxyprogesterone acetate. This review is a summary of the cellular and molecular mechanisms of bone turnover, the pathophysiology of osteoporosis, and their treatment. Nuclear factor-κβ ligand (RANKL) appears to be the critical uncoupling factor that enhances osteoclastogenesis. In contrast, osteoprotegerin (OPG) is a RANKL antagonist secreted by osteoblast lineage cells. Estrogen promotes apoptosis of osteoclasts and inhibits osteoclastogenesis by stimulating the production of OPG and reducing osteoclast differentiation after suppression of IL-1 and TNF, and subsequent M-CSF, RANKL, and IL-6 release. It can also activate the Wnt signaling pathway to increase osteogenesis, and upregulate BMP signaling to promote mesenchymal stem cell differentiation from pre-osteoblasts to osteoblasts rather than adipocytes. Estrogen deficiency leads to the uncoupling of bone resorption and formation; therefore, resulting in greater bone loss. Excessive glucocorticoids increase PPAR-2 production, upregulate the expression of Dickkopf-1 (DKK1) in osteoblasts, and inhibit the Wnt signaling pathway, thus decreasing osteoblast differentiation. They promote osteoclast survival by enhancing RANKL expression and inhibiting OPG expression. Appropriate estrogen supplement and avoiding excessive glucocorticoid use are deemed the primary treatment for hormone-related and glucocorticoid-induced osteoporosis. Additionally, current pharmacological treatment includes bisphosphonates, teriparatide (PTH), and RANKL inhibitors (such as denosumab). However, many detailed cellular and molecular mechanisms underlying osteoporosis seem complicated and unexplored and warrant further investigation.

A preliminary study on the relationship between environmental endocrine disruptors and precocious puberty in girls

OBJECTIVES

To explore the associations of environmental endocrine disruptors on precocious puberty in girls.

METHODS

This was a case-control study in which 30 girls with precocious puberty and 46 age- and race-matched prepubertal females were enrolled. The concentrations of 10 environment endocrine disruptors (bisphenol A, bisphenol B, butylparaben, propylparaben, ethvlparaben, methylparaben, mono-butyl phthalate, mono-2-ethylhexyl phthalate, monoethyl phthalate, and monomethyl phthalate) in urine and 10 steroid hormones (dihydrotestosterone, corticosterone, hydrocortisone, 11-deoxycortisol, 17α-hydroxy progesterone, 4-androstene-3,17-dione, estrone, deoxycorticosterone, pregnenolone, and dehydroepiandrosterone) in serum were detected with the liquid chromatography-mass spectrometry (LC-MS).

RESULTS

According to the Mann-Whitney U test, urinary levels of bisphenol A, monobutyl phthalate, and monomethyl phthalate were significantly higher in the precocious group than in the prepubertal group, and blood levels of hydrocortisone, 11-deoxycortisol, corticosterone, deoxycorticosterone, and pregnenolone were significantly lower in the precocious group than in the prepubertal group (p<0.05, VIP>1).

CONCLUSIONS

Our findings confirm the association between phthalate exposure and the incidence of precocious puberty in girls. Control and reduction of children exposure to phthalate esters should be considered as a health priority.

Association between dehydroepiandrosterone sulphate levels at 7 years old and bone mineral density at 10 years old: a prospective cohort study

We aimed to explore the effect of dehydroepiandrosterone sulphate (DHEAS) at age 7 on areal bone mineral density (aBMD) at age 10 and to distinguish the direct and indirect effects (explained by sexual maturity and by aBMD at age 7), for each sex, after adjustment for body mass index (BMI) z-score. In a subsample of 274 children (139 girls, 135 boys) from Generation XXI cohort, aBMD was assessed with dual-energy X-ray absorptiometry (DXA) scan at ages 7 and 10. The increase in aBMD at age 10 for each 10 µg/dL increase in DHEAS levels at age 7 was estimated using path analysis. Both the direct and the indirect effects were calculated. In girls, higher DHEAS levels at age 7 were associated with higher aBMD at age 10. No direct effect was observed. The indirect effect via higher aBMD at age 7 explained 61% of the total effect, and the indirect effect via higher Tanner stage explained 21%. After adjustment for BMI, the total effect remained statistically significant, explained in 33% by the indirect effect of DHEAS on Tanner stage and Tanner stage on aBMD. In boys, no effect of DHEAS on aBMD was observed.

CONCLUSION

An indirect effect of DHEAS at age 7 on aBMD at age 10 was found in girls, but not in boys, as higher DHEAS levels were associated with more advanced sexual maturation at age 10, and more advanced sexual maturation to higher aBMD. No direct effect of DHEAS on aBMD was observed.

WHAT IS KNOWN

• Conditions associated with elevated DHEAS, adrenarche's biomarker, are accompanied by advanced bone maturity. • Whether adrenal androgens influence bone mineralization in childhood remains puzzling, and longitudinal data is scarce.

WHAT IS NEW

• In girls, but not in boys, higher DHEAS at age 7 was associated with higher aBMD at age 10. • This was partially explained by the indirect effect of DHEAS at age 7 on sexual maturity at age 10, as DHEAS at age 7 was positively associated with sexual maturity at age 10, which was further associated with aBMD.

Normal and Premature Adrenarche

Adrenarche is the maturational increase in adrenal androgen production that normally begins in early childhood. It results from changes in the secretory response to adrenocorticotropin (ACTH) that are best indexed by dehydroepiandrosterone sulfate (DHEAS) rise. These changes are related to the development of the zona reticularis (ZR) and its unique gene/enzyme expression pattern of low 3ß-hydroxysteroid dehydrogenase type 2 with high cytochrome b5A, sulfotransferase 2A1, and 17ß-hydroxysteroid dehydrogenase type 5. Recently 11-ketotestosterone was identified as an important bioactive adrenarchal androgen. Birth weight, body growth, obesity, and prolactin are related to ZR development. Adrenarchal androgens normally contribute to the onset of sexual pubic hair (pubarche) and sebaceous and apocrine gland development. Premature adrenarche causes ≥90% of premature pubarche (PP). Its cause is unknown. Affected children have a significantly increased growth rate with proportionate bone age advancement that typically does not compromise growth potential. Serum DHEAS and testosterone levels increase to levels normal for early female puberty. It is associated with mildly increased risks for obesity, insulin resistance, and possibly mood disorder and polycystic ovary syndrome. Between 5% and 10% of PP is due to virilizing disorders, which are usually characterized by more rapid advancement of pubarche and compromise of adult height potential than premature adrenarche. Most cases are due to nonclassic congenital adrenal hyperplasia. Algorithms are presented for the differential diagnosis of PP. This review highlights recent advances in molecular genetic and developmental biologic understanding of ZR development and insights into adrenarche emanating from mass spectrometric steroid assays.

The Steroid Metabolome and Breast Cancer Risk in Women with a Family History of Breast Cancer: The Novel Role of Adrenal Androgens and Glucocorticoids

BACKGROUND

No study has comprehensively examined how the steroid metabolome is associated with breast cancer risk in women with familial risk.

METHODS

We examined 36 steroid metabolites across the spectrum of familial risk (5-year risk ranged from 0.14% to 23.8%) in pre- and postmenopausal women participating in the New York site of the Breast Cancer Family Registry (BCFR). We conducted a nested case-control study with 62 cases/124 controls individually matched on menopausal status, age, and race. We measured metabolites using GC-MS in urine samples collected at baseline before the onset of prospectively ascertained cases. We used conditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) per doubling in hormone levels.

RESULTS

The average proportion of total steroid metabolites in the study sample were glucocorticoids (61%), androgens (26%), progestogens (11%), and estrogens (2%). A doubling in glucocorticoids (aOR = 2.7; 95% CI = 1.3-5.3) and androgens (aOR = 1.6; 95% CI = 1.0-2.7) was associated with increased breast cancer risk. Specific glucocorticoids (THE, THF αTHF, 6β-OH-F, THA, and α-THB) were associated with 49% to 161% increased risk. Two androgen metabolites (AN and 11-OH-AN) were associated with 70% (aOR = 1.7; 95% CI = 1.1-2.7) and 90% (aOR = 1.9; 95% CI = 1.2-3.1) increased risk, respectively. One intermediate metabolite of a cortisol precursor (THS) was associated with 65% (OR = 1.65; 95% CI = 1.0-2.7) increased risk. E1 and E2 estrogens were associated with 20% and 27% decreased risk, respectively.

CONCLUSIONS

Results suggest that glucocorticoids and 11-oxygenated androgens are positively associated with breast cancer risk across the familial risk spectrum.

IMPACT

If replicated, our findings suggest great potential of including steroids into existing breast cancer risk assessment tools.

Quantitative ultrasound screening of bone mineral density on children with short stature

Objectives:

To assess bone mineral density (BMD) of children with short stature using quantitative ultrasound (QUS) and compare it to children with normal height.

Methods:

We conducted a descriptive, cross-sectional controlled study between May 2018 and February 2019 at various pediatric clinics in Jeddah, Saudi Arabia. In total, 219 children were included: 100 had short stature, and 119 were of normal height. Data were collected from one-on-one interviews, and BMD was measured using quantitative ultrasound.

Results:

Children with short stature had significantly lower BMD z-scores than children with normal height (p<0.05). The use of vitamin D supplements was related to higher BMD z-scores in children with short stature (p<0.05). A significant association was found between higher BMD z-scores, and both age (p=0.05) and height (p=0.02). Through a further division of children with short stature into those with and those without growth hormone deficiencies, we show that growth hormone deficiency was positively associated with lower BMD z-scores; however, the p-value was 0.06.

Conclusions:

Compared with children of normal height, those with short stature had lower BMD. Height, vitamin D supplementation, and age were all significantly correlated with higher BMD, while growth hormone deficiency was correlated with lower BMD.

Determinants of bone mineral density through quantitative ultrasound screening of healthy children visiting ambulatory paediatric clinics

Objectives:

To investigate the determinants of bone mineral density through screening healthy children using a non-invasive quantitative ultrasound measurement device.

Methods:

A descriptive cross-sectional study carried out at King AbdulAziz University Hospital, Jeddah, Kingdom of Saudi Arabia. between May 2018 and January 2019 through interviewing, examining, and screening healthy children visiting general paediatric. Total sample size encompassed 450 children. The inclusion criteria were healthy children between the ages of 2 and 20 years. Exclusion criteria were previous pathological fractures, chronic medical diseases, or long-term medications. Data entry and analysis was conducted using Statistical Package for Social Sciences version 24 (IBM Corp, Armonk, NY, USA). Chi-square tests were used to determine the association between categorical variables, with calculated p<0.05 considered significant. With one-way Anova testing to study the relationship between categorical variables and continuous variables.

Results:

A significant association with bone mineral density (BMD) was found during first 2 years with height (p=0.015), vitamin D supplementation (p=0.03), and breastfeeding (p=0.025). A directly proportional relationship with BMD was found with pubertal status, physical activity, diet, sun exposure, and calcium supplement intake.

Conclusion:

This is a novel study in the investigation of the dietary, lifestyle and demographic determinants of bone mineral density in the healthy middle-eastern child otherwise unaffected by chronic medical or metabolic disease or exposed to long term medications that could have affected bone metabolism.

The art of measuring steroids: Principles and practice of current hormonal steroid analysis

Steroids are small and highly important structural or signalling molecules in living organisms and their metabolism is complex. Due to the multiplicity of enzymes involved there are many different steroid related disorders. E.g., an individual enzyme defect is rather rare but can share various clinical symptoms and can thus be hardly diagnosed clinically. Therefore, reliable hormonal determination still presents the most reasonable initial diagnostic approach and helps to avoid uncritical and expensive attempts at molecular diagnostic testing. It also presents a backbone of monitoring these complex patients. In science, reliable hormone measurement is indispensable for the elucidation of new mechanisms of steroid hormone actions. Steroid analytics is highly challenging and should never be considered trivial. Most common methods for steroid determination comprise traditionally immunoassay, or more recently, mass spectrometry based methods. It is absolutely necessary that clinicians and scientists know the methods they are applying by heart. With the introduction of automated direct assays, a loss of quality could be observed over the last two decades in the field of steroid immunoassays. This review wants to meet the need for profound information and orientation in the field of steroid analysis. The pros and cons of the most important methods, such as immunoassays and mass spectrometry based methods will be discussed. The focus of the latter will lie on gas chromatography-mass spectrometry (GC-MS) as well as liquid chromatography-mass spectrometry (LC-MS). Selected analytical applications from our Deutsche Forschungsgemeinschaft Research Group FOR 1369 "Sulfated Steroids in Reproduction" will illustrate the contents. In brief, immunoassays have for long presented the traditional technique for steroid analysis. They are easy to set up. Only one analyte can be measured per immunoassay. Specificity problems can arise and caution has to be exerted especially regarding direct assays lacking purification steps. Mass spectrometry based methods provide structural information on the analyte and thus higher specificity. In combination with chromatographic techniques, they permit the simultaneous determination of a multitude of analytes. Highest specificity can be obtained using GC-MS, a sophisticated but most powerful tool for characterizing steroid metabolomes. LC-MS is a true high throughput technique and highly suited for detecting complex steroids. GC-MS and LC-MS are not competing but complementary techniques. Since reliable steroid determination requires extremely high expertise in the field of analytics as well as steroid biochemistry, it is recommended that collaborations and networking with highly specialized centers of expertise are developed.

Investigating the Prevalence of Low Bone Mass in Children of Southern Iran and Its Associated Factors

BACKGROUND

Improving peak bone mass and bone strength in the first years of life and enhancing it during young adulthood could prevent osteoporosis and fractures in the last years of life. We evaluated the prevalence of low bone mass in the lumbar and femoral neck and its associated factors in southern Iranian children.

METHODS

This is a cross-sectional study on healthy Iranian children aged 9 - 18 years old during 2011 - 2012. Dual energy X-ray absorptiometry (DEXA) was used for measuring bone mineral density (BMD). BMD Z-score ≤ -2 was considered as low. Anthropometric data, physical activity, sun exposure, puberty, and mineral biochemical parameters were assessed. Data were analyzed using SPSS v.15.

RESULTS

477 normal children, including 236 (49.5%) girls and 241 (50.5%) boys, aged 13.8 ± 2.7 years were enrolled. Prevalence of low bone mass (LBM) in the femoral and lumbar region was 10.7% and 18.7%, respectively. The prevalence of LBM in femur of girls is twice more than boys. Fat mass index, BMI Z-score, and physical activity were associated with lumbar low bone mass. BMI Z-score and physical activity were associated with femoral low bone mass.

CONCLUSIONS

High prevalence of low bone mineral density in children 9 to 18 years in south of the country is concerned and is needed to plan for prevention and treatment. BMI-Z score, fat mass index, and physical activity were the 3 most important preventive factors in developing low bone mass in children.

Longitudinal bone mineral content and density in Rett syndrome and their contributing factors

Bone mass and density are low in females with Rett syndrome. This study used Dual energy x-ray absorptiometry to measure annual changes in z-scores for areal bone mineral density (aBMD) and bone mineral content (BMC) in the lumbar spine and total body in an Australian Rett syndrome cohort at baseline and then after three to four years. Bone mineral apparent density (BMAD) was calculated in the lumbar spine. Annual changes in lean tissue mass (LTM) and bone area (BA) were also assessed. The effects of age, genotype, mobility, menstrual status and epilepsy diagnosis on these parameters were also investigated. The baseline sample included 97 individuals who were representative of the total live Australian Rett syndrome population under 30years in 2005 (n=274). Of these 74 had a follow-up scan. Less than a quarter of females were able to walk on their own at follow-up. Bone area and LTM z-scores declined over the time between the baseline and follow-up scans. Mean height-standardised z-scores for the bone outcomes were obtained from multiple regression models. The lumbar spine showed a positive mean annual BMAD z-score change (0.08) and a marginal decrease in aBMD (-0.04). The mean z-score change per annum for those 'who could walk unaided' was more positive for LS BMAD (p=0.040). Total body BMD mean annual z-score change from baseline to follow-up was negative (-0.03). However this change was positive in those who had achieved menses prior to the study (0.03, p=0,040). Total body BMC showed the most negative change (-0.60), representing a decrease in bone mineral content over time. This normalised to a z-score change of 0.21 once adjusted for the reduced lean tissue mass mean z-score change (-0.21) and bone area mean z-score change (-0.14). Overall, the bone mineral content, bone mineral density, bone area and lean tissue mass z-scores for all outcome measures declined, with the TB BMC showing significant decreases. Weight, height and muscle mass appear to have impacts on bone formation and we recommend that nutritional intake should be closely monitored and a physical activity plan developed to optimise bone health. Pubertal progression should also be assessed in conjunction with serial densitometry assessments to track bone mass and density changes over time.

Cortical bone mineral density in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

BACKGROUND

Prior studies reveal that bone mineral density (BMD) in congenital adrenal hyperplasia (CAH) is mostly in the osteopaenic range and is associated with lifetime glucocorticoid dose. The forearm, a measure of cortical bone density, has not been evaluated.

OBJECTIVE

We aimed to evaluate BMD at various sites, including the forearm, and the factors associated with low BMD in CAH patients.

METHODS

Eighty CAH adults (47 classic, 33 nonclassic) underwent dual-energy-x-ray absorptiometry and laboratory and clinical evaluation. BMD Z-scores at the AP spine, total hip, femoral neck, forearm and whole body were examined in relation to phenotype, body mass index, current glucocorticoid dose, average 5-year glucocorticoid dose, vitamin D, 17-hydroxyprogesterone, androstenedione, testosterone, dehydroepiandrosterone and dehydroepiandrosterone sulphate (DHEAS).

RESULTS

Reduced BMD (T-score <-1 at hip, spine, or forearm) was present in 52% and was more common in classic than nonclassic patients (P = 0·005), with the greatest difference observed at the forearm (P = 0·01). Patients with classic compared to nonclassic CAH, had higher 17-hydroxyprogesterone (P = 0·005), lower DHEAS (P = 0·0002) and higher non-traumatic fracture rate (P = 0·0005). In a multivariate analysis after adjusting for age, gender, height standard deviation, phenotype and cumulative glucocorticoid exposure, higher DHEAS was independently associated with higher BMD at the spine, radius and whole body.

CONCLUSION

Classic CAH patients have lower BMD than nonclassic patients, with the most affected area being the forearm. This first study of forearm BMD in CAH patients suggests that low DHEAS may be associated with weak cortical bone independent of glucocorticoid exposure.

Higher glucocorticoid secretion in the physiological range is associated with lower bone strength at the proximal radius in healthy children: importance of protein intake adjustment

Whether higher production of glucocorticoids (GCs) within the physiological range may already be affecting bone status in healthy children is unknown. Because dietary protein intake affects both bone and GCs, we examined the association of urinary measures of glucocorticoid status and cortical bone in healthy non-obese children, after particularly controlling for protein intake. Proximal forearm bone parameters were measured by peripheral quantitative computed tomography (pQCT). Subjects studied (n = 175, 87 males, aged 6 to 18 years) had two 24-hour urine samples collected: the first sample at 1 year before bone measurement, and the second sample at the time of bone measurement. Major urinary GC metabolites were measured by mass spectrometry and summed to assess daily adrenal GC secretion (∑C21). Urinary free cortisol (UFF) and cortisone (UFE) were summed to assess potentially bioactive free GCs (UFF + UFE). After controlling for several covariates and especially urinary nitrogen (the biomarker of protein intake) cortisol secretion ∑C21 was inversely associated with all analyzed pQCT measures of bone quality. ∑C21 also predicted a higher endosteal and lower periosteal circumference, explaining both a smaller cortical area and (together with lower BMD) a lower strength-strain-index (SSI). UFF + UFE, UFE itself, and a urinary metabolite-estimate of 11beta-hydroxysteroid dehydrogenase type1 (11beta-HSD1) activity showed corresponding reciprocal associations (p < 0.05) with BMD and bone mineral content, but not with SSI and bone geometry variables. In conclusion, higher GC levels, even within the physiological range, appear to exert negative influences on bone modeling and remodeling already during growth. Our physiological data also suggest a relevant role of cortisone as the direct source for intracrine-generated cortisol by bone cell 11beta-HSD1.

Fetal and childhood growth patterns associated with bone mass in school-age children: the Generation R Study

Low birth weight is associated with lower bone accrual in children and peak bone mass in adults. We assessed how different patterns of longitudinal fetal and early childhood growth influence bone properties at school age. In 5431 children participating in a population-based prospective cohort study, we measured fetal growth by ultrasound at 20 and 30 weeks gestation, and childhood growth at birth, 1, 2, 3, and 4 years of age. We analyzed these growth measurements in relation to total body (less head) BMD measured by DXA at age 6. We used conditional growth modeling; a technique which takes into account correlation between repeatedly measured growth measures. Our results showed that estimated fetal weight gain, femur length growth between 20 and 30 weeks of gestation, femur length growth between 30 weeks and birth, as well as all height and weight growth measurements from birth to 4 years of age were all positively associated with BMC, bone area (BA), and BMD (all p < 0.01). Fetal femur length growth between 30 weeks and birth was positively associated with BMC and BA (both p < 0.001), but not with BMD. Overall, childhood growth measurements exerted a larger influence on bone measures than fetal growth measures. The strongest effect estimate was observed during the first year of life. Children born small (<10th percentile) for gestational age (SGA) had lower BMC and BA, but not BMD, than children born appropriate for gestational age (AGA), whereas children born large (>90th percentile) for gestational age (LGA) had higher BMC and BA (all p < 0.001). These differences were no longer present in children showing subsequent accelerated and decelerated infant growth, respectively. We conclude that both fetal and childhood growth patterns are associated with bone mineral accrual, showing the strongest effect estimates in infancy. Compensatory infant growth counteracts the adverse consequences of fetal growth restriction on bone development.

Relation of adrenal-derived steroids with bone maturation, mineral density and geometry in healthy prepubertal and early pubertal boys

BACKGROUND

Little is known about the effects of adrenal steroids on skeletal maturation and bone mass acquisition in healthy prepubertal boys.

OBJECTIVE

To study whether adrenal-derived steroids within the physiological range are associated with skeletal maturation, areal and volumetric bone mineral density (aBMD and vBMD) and bone geometry in healthy prepubertal and early pubertal boys.

METHODS

98 healthy prepubertal and early pubertal boys (aged 6-14 y) were studied cross-sectionally. Androstenedione (A) and estrone (E1) were determined by liquid chromatography tandem mass spectrometry and DHEAS was determined by immunoassay. Whole body and lumbar spine aBMD and bone area were determined by dual-energy X-ray absorptiometry. Trabecular (distal site) and cortical (proximal site) vBMD and bone geometry were assessed at the non-dominant forearm and leg using peripheral QCT. Skeletal age was determined by X-ray of the left hand.

RESULTS

Adrenal-derived steroids (DHEAS, A and E1) are positively associated with bone age in prepubertal and early pubertal children, independently of age. There are no associations between the adrenal-derived steroids and the studied parameters of bone size (lumbar spine and whole body bone area, trabecular or cortical area at the radius or tibia, periosteal circumference and cortical thickness at the radius or tibia) or BMD (aBMD or vBMD).

CONCLUSION

In healthy prepubertal and early pubertal boys, serum adrenal-derived steroid levels, are associated with skeletal maturation, independently of age, but not with bone size or (v)BMD. Our data suggest that adrenal derived steroids are not implicated in the accretion of bone mass before puberty in boys.

Association between lean and fat mass and indicators of bone health in prepubertal caucasian children

BACKGROUND/AIMS

Childhood and adolescence are critical periods for bone growth. The independent association between lean and fat mass and indicators of bone health in children is not yet known. We aim to examine the association between each of lean and fat mass and indicators of bone health in 8- to 10-year-old prepubertal Caucasian children.

METHODS

We present a cross-sectional analysis of baseline data from the QUebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort which study the natural history of obesity. Study participants (n = 483) included prepubertal children aged 8-10 years and their biological parents. Whole-body bone mineral content (BMC, g), bone area (cm²), bone mineral density (BMD, g/cm²), lean mass (kg), and fat mass (kg) were measured by dual-energy X-ray absorptiometry. Data analyses include multiple linear regressions adjusted for potential confounding variables.

RESULTS

A 1-kg increase in lean mass was associated with 28.42 g, 19.88 cm², and 0.007 g/cm² increase in whole-body BMC, bone area and BMD respectively. A 1-kg increase in fat mass was associated with 9.32 g, 8.02 cm², and 0.002 g/cm² increase in whole-body BMC, bone area and BMD, respectively.

CONCLUSION

Increasing lean mass in children may help optimize bone acquisition and prevent future osteoporosis.

Virilization of a young girl caused by concomitant ectopic and intra-adrenal adenomas of the adrenal cortex

BACKGROUND

Adenomas of the adrenal gland are rare causes of virilization in childhood.

CASE REPORT

A girl aged 2 years and 4 months presented with pubarche, distinct clitoral hypertrophy, tall stature, and increased height velocity. Plasma testosterone and dehydroepiandrosterone were elevated. Androgens remained unchanged after adrenocorticotropic hormone, and dexamethasone administrations. Ultrasound examination and magnetic resonance imaging indicated an extra-adrenal mass adjacent to the left adrenal gland, which was removed by endoscopic surgery. However, plasma androgens remained elevated and (131)I-iodomethyl-norcholesterol scintigraphy revealed tracer enhancement in the right adrenal gland, which was consecutively removed. Virilization regressed after extirpation of the adenomas and height velocity normalized.

RESULTS

Histology revealed a circumscribed adenoma in the right adrenal gland and an epithelial mass with adrenal cortical cells in the left-sided ectopic tumor. In the ectopic tumor, melanocortin 2 receptor expression was augmented threefold compared to the control, indicating adrenal origin.

CONCLUSIONS

In this young girl, virilization is due to concomitant ectopic and intra-adrenal adenomas of the adrenal cortex. By melanocortin 2 receptor expression, it was confirmed that the ectopic adenoma derived from the adrenal cortex. Specific scintigraphy, if available, assists in allocating the source of androgen hypersecretion.

Hair analysis in health assessment

BACKGROUND

Hair analysis is used for estimation of the nutritional status of individuals. In the present work, a systematic review on the relation between the mineral composition of hair and the physical or mental disorders is discussed. Detailed information of examined populations, methods of sample preparations and analytical techniques are presented.

METHODS

A systematic literature search in four electronic databases Scopus, PubMed, Web of Science and Medline (from 1997 to 2012/01/31) for English language articles was performed. In addition, a reference list and manual search was undertaken.

RESULTS

The following number of studies was included: 66. Most of the authors reported that there exists a correlation between deficiency or excess of some elements in hair and occurrence of some diseases, such as: autism, cancer, hypertension, myocardial infarction, kidney disease and diabetes mellitus. However, not all results were consistent.

CONCLUSIONS

Most of the authors concluded that the profile of hair mineral imbalance might be useful as a diagnostic tool for the early diagnosis of many diseases. However, it seems that there is a need to standardize sample preparation procedures, in particular washing and mineralization methods.

Adrenarche and middle childhood

Middle childhood, the period from 6 to 12 years of age, is defined socially by increasing autonomy and emotional regulation, somatically by the development of anatomical structures for subsistence, and endocrinologically by adrenarche, the adrenal production of dehydroepiandrosterone (DHEA). Here I suggest that DHEA plays a key role in the coordinated development of the brain and body beginning with middle childhood, via energetic allocation. I argue that with adrenarche, increasing levels of circulating DHEA act to down-regulate the release of glucose into circulation and hence limit the supply of glucose which is needed by the brain for synaptogenesis. Furthermore, I suggest the antioxidant properties of DHEA may be important in maintaining synaptic plasticity throughout middle childhood within slow-developing areas of the cortex, including the insula, thamalus, and anterior cingulate cortex. In addition, DHEA may play a role in the development of body odor as a reliable social signal of behavioral changes associated with middle childhood.

Long term higher urinary calcium excretion within the normal physiologic range predicts impaired bone status of the proximal radius in healthy children with higher potential renal acid load

Reduced bone mineral density (BMD) and bone mass have been observed in children with idiopathic hypercalciuria. Whether urinary calcium excretion at the higher end of the normal physiologic range can influence bone health in healthy children independent of dietary intake is unknown. Urinary calcium was quantified in 603 24-h urine samples from 154 healthy children and adolescents who had ≥3 urine collections and parallel 3-day weighed dietary records during the 4years preceding proximal forearm bone analyses by peripheral quantitative computed tomography (pQCT). Urinary potential renal acid load (uPRAL) was determined according to urine ionogram by subtracting measured quantitatively important mineral cations from nonbicarbonate anions. Urinary calcium excretion was significantly associated with volumetric (v)BMD (P=0.04), almost significantly with cortical bone mineral content (BMC) (P=0.05), but not with cortical cross-sectional area (CSA) (P=0.09), total CSA (P=0.3), or Strength-Strain Index (P=0.8) in the total population sample. Stratified analyses based on the median split of uPRAL showed that calcium excretion was negatively associated with vBMD (P=0.007), cortical BMC (P=0.001), and cortical CSA (P=0.004) in those children with higher uPRALs, but not in those with low uPRALs (P>0.3). In conclusion, long-term higher calciuria within the physiological range predicts reduced diaphyseal bone mass and bone density particularly in healthy children and adolescents with long-term unfavorable higher dietary acid load, i.e., with lower fruit and vegetable intake.

Increased activation of the alternative "backdoor" pathway in patients with 21-hydroxylase deficiency: evidence from urinary steroid hormone analysis

BACKGROUND

17-Hydroxyprogesterone (17-OHP) can be converted to dihydrotestosterone (DHT) via an alternative "backdoor" route that bypasses the conventional intermediates androstenedione and testosterone. In this backdoor pathway, 17-OHP is converted to 5α-pregnane-3α,17α-diol-20-one (pdiol), which is an excellent substrate for the 17,20 lyase activity of CYP17A1 to produce androsterone. OBJECTIVE AND HYPOTHESES: The objective of this study was to obtain evidence for the presence of the backdoor pathway in patients with 21-hydroxylase deficiency (21-OHD).

METHODS

We compared urinary steroid hormone profiles determined by gas chromatography-mass spectrometry of 142 untreated 21-OHD patients (age range, 1 d to 25.4 yr; 51 males) with 138 control subjects. The activity of the backdoor pathway was assessed using the ratios of the urinary concentrations of pdiol to those of the metabolites of the classic Δ4 and Δ5 pathways. In contrast to etiocholanolone, which originates almost exclusively from the classic pathways, androsterone may be derived additionally from the backdoor pathway. Therefore, the androsterone to etiocholanolone ratio can be used as an indicator for the presence of the backdoor pathway.

RESULTS

Untreated 21-OHD subjects showed increased urinary ratios of pdiol to the Δ4 and Δ5 pathway metabolites and a higher androsterone to etiocholanolone ratio.

CONCLUSIONS

The elevated ratios of pdiol to the Δ4 and Δ5 pathway metabolites as well as the higher androsterone to etiocholanolone ratio in patients with 21-OHD indicate postnatal activity of the backdoor pathway with maximum activity during early infancy. Our data provide new insights into the pathophysiology of androgen biosynthesis of 21-OHD.

Long-term high urinary potential renal acid load and low nitrogen excretion predict reduced diaphyseal bone mass and bone size in children

BACKGROUND

Longitudinal diet assessment data in children suggest bone anabolic effects of protein intake and concurrent catabolic effects of dietary acid load. However, studies using valid biomarker measurements of corresponding dietary intakes are lacking.

OBJECTIVE

The aim of the study was to examine whether the association of long-term dietary acid load and protein intake with children's bone status can be confirmed using approved urinary biomarkers and whether these diet influences may be independent of potential bone-anabolic sex steroids.

METHOD

Urinary nitrogen (uN), urinary net acid excretion (uNAE), and urinary potential renal acid load (uPRAL) were quantified in 789 24-h urine samples of 197 healthy children who had at least three urine collections during the 4 yr preceding proximal forearm bone analyses by peripheral quantitative computed tomography. uPRAL was determined by subtracting measured mineral cations (sodium + potassium + calcium + magnesium) from measured nonbicarbonate anions (chloride + phosphorus + sulfate). In a subsample of 167 children, dehydroepiandrosterone metabolites were quantified by gas chromatography-mass spectrometry. Multivariable regression models adjusted for age, sex, pubertal stage, forearm muscle area, forearm length, and urinary calcium were run with uN and/or uPRAL or uNAE as predictors.

RESULTS

uN was positively associated with bone mineral content, cortical area, periosteal circumference, and strength strain index. uPRAL (but not uNAE) showed negative associations with bone mineral content and cortical area (P < 0.05), both with and without adjustment for the dehydroepiandrosterone-derived sex steroid androstenediol.

CONCLUSIONS

In line with dietary assessment findings, urinary biomarker analyses substantiate long-term positive effects of protein intake and concomitant negative effects of higher dietary acid load on bone status of children, independent of bone-anabolic sex steroid action.

Premature adrenarche: novel lessons from early onset androgen excess

Adrenarche reflects the maturation of the adrenal zona reticularis resulting in increased secretion of the adrenal androgen precursor DHEA and its sulphate ester DHEAS. Premature adrenarche (PA) is defined by increased levels of DHEA and DHEAS before the age of 8 years in girls and 9 years in boys and the concurrent presence of signs of androgen action including adult-type body odour, oily skin and hair and pubic hair growth. PA is distinct from precocious puberty, which manifests with the development of secondary sexual characteristics including testicular growth and breast development. Idiopathic PA (IPA) has long been considered an extreme of normal variation, but emerging evidence links IPA to an increased risk of developing the metabolic syndrome (MS) and thus ultimately cardiovascular morbidity. Areas of controversy include the question whether IPA in girls is associated with a higher rate of progression to the polycystic ovary syndrome (PCOS) and whether low birth weight increases the risk of developing IPA. The recent discoveries of two novel monogenic causes of early onset androgen excess, apparent cortisone reductase deficiency and apparent DHEA sulphotransferase deficiency, support the notion that PA may represent a forerunner condition for PCOS. Future research including carefully designed longitudinal studies is required to address the apparent link between early onset androgen excess and the development of insulin resistance and the MS.

The role of GH/IGF-I-mediated mechanisms in sex differences in cortical bone size in mice

Cortical bone dimensions are important determinants of bone strength. Gender differences in cortical bone size caused by greater periosteal expansion in males than in females during the pubertal growth spurt are well established both in humans and in experimental animal models. However, the mechanism by which gender influences cortical bone size is still a matter of investigation. The role of androgens and estrogen in pubertal bone growth has been examined in human disorders as well as animal models, such as gonadectomized or sex steroid receptor knockout mice. Based on the findings that growth hormone (GH) and insulin-like growth factor I (IGF-I) are major regulators of postnatal skeletal growth, we and others have predicted that sex hormones interact with the GH/IGF-I axis to regulate cortical bone size. However, studies conflict as to whether estrogen and androgens impact cortical bone size through the canonical pathway, through GH without IGF-I mediation, through IGF-I without GH stimulation, or independent of GH/IGF-I. We review recent data on the impact of sex steroids and components of the GH/IGF axis on sexual dimorphism in bone size. While the GH/IGF-I axis is a major player in regulating peak bone size, the relative contribution of GH/IGF-dependent mechanisms to sex differences in cortical bone size remains to be established.

Prepubertal healthy children's urinary androstenediol predicts diaphyseal bone strength in late puberty

CONTEXT

During the physiological process of adrenarche, the adrenal glands of healthy children secrete increasing amounts of weak androgenic steroids partly metabolized to potent sex steroids.

OBJECTIVE

The aim of the study was to examine whether adrenal androgen metabolite excretion rates before the onset of puberty may be prospectively associated with late-pubertal diaphyseal bone strength.

SETTING

We conducted the study in an auxological and metabolic child nutrition research facility.

STUDY POPULATION AND DESIGN

The sample included 45 healthy adolescents who underwent proximal forearm bone and muscle area measurements by peripheral quantitative computed tomography at the age of 16 yr (SD 1.5) and who had collected a 24-h urine sample 8 yr earlier, allowing to quantify the prepubertal urine metabolome. Prepubertal hormonal predictors quantified by gas chromatography-mass spectrometry were: dehydroepiandrosterone, its 16-hydroxylated downstream metabolites, 5-androstene-3beta,17beta-diol (androstenediol), sums of total androgen and glucocorticoid metabolites, cortisol, and 6beta-hydroxycortisol.

MAIN OUTCOMES

Proximal forearm radius was measured.

RESULTS

Of all prepubertal hormones analyzed, only sex- and age-specific androstenediol levels significantly predicted pubertal stage-, height-, and muscularity-adjusted diaphyseal bone modeling (periosteal circumference, beta = 0.67, P = 0.002; cortical area, beta = 2.15, P = 0.02), bone mineral content (beta = 2.2; P = 0.04), and polar strength strain index (beta = 12.2; P = 0.002). Androstenediol explained 5-10% of the late-pubertal diaphyseal radius variability.

CONCLUSIONS

Our prospective profiling of urinary steroid metabolites in 24-h urine samples collected before puberty suggests that androstenediol is an early predictor of the diaphyseal bone strength in late puberty. This predominantly peripheral conversion product of adrenarchal dehydroepiandrosterone by 17beta-hydroxysteroid dehydrogenase may hence be involved in a sustained improvement of radial bone accretion during growth.

Reduced bone cortical thickness in boys with autism or autism spectrum disorder

Bone development, casein-free diet use, supplements, and medications were assessed for 75 boys with autism or autism spectrum disorder, ages 4-8 years. Second metacarpal bone cortical thickness (BCT), measured on hand-wrist radiographs, and % deviations in BCT from reference medians were derived. BCT increased with age, but % deviations evidenced a progressive fall-off (p = .02): +3.1 +/- 4.7%, -6.5 +/- 4.0%, -16.6 +/- 3.4%, -19.4 +/- 3.7%,-24.1 +/- 4.4%, at ages 4-8, respectively, adjusting for height. The 12% of the boys on casein-free diets had an overall % deviation of -18.9 +/- 3.7%, nearly twice that of boys on minimally restricted or unrestricted diets (-10.5 +/- 1.3%, p < .04), although even for boys on minimally restricted or unrestricted diets the % deviation was highly significant (p < .001). Our data suggest that the bone development of autistic boys should be monitored as part of routine care, especially if they are on casein-free diets.

Bone mineral density of young boy soccer players at different pubertal stages: relationships with hormonal concentration

OBJECTIVES

To examine the effects of soccer in relation with the hormonal concentration, on the bone mass of young Tunisian players at different pubertal stages.

METHODS

Two groups of 152 young boys (age: 13.3+/-0.9 years) participated in this study: (1) 91 soccer players, and (2) 61 non-athletic boys used as control subjects. The bone mineral density (BMD) and the bone mineral content (BMC) were measured by dual-energy X-ray absorptiometry (DXA). Pubertal stages were assessed, and serum concentrations of insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), growth hormone (GH) and the total testosterone were measured.

RESULTS

The BMD and BMC for whole body, lumbar spine, femoral neck, pelvis and lower limbs were higher in soccer players than in controls (p<0.001). In early puberty, the soccer players also exhibited significantly greater BMD and BMC in the whole body and in weight-bearing bones compared with the controls (p<0.001). However, there was no intersubject variability due to puberty in either BMD or BMC. The pubescent soccer players had significantly higher hormonal concentrations of IGF-1 and IGFBP-3 than their counterpart controls (p<0.05). Moreover, the whole body BMD was significantly (p<0.001) correlated with GH, IGF-1 and IGFBP-3 but not with the testosterone concentrations.

CONCLUSION

The soccer participation of boys is generally associated with the improvement of their bone mass which is mainly marked at early and late puberty. The relationships between somatotropic axis hormones and BMD of the players may be linked to the parallel development of these two parameters during puberty.

Current concepts in bone and reproductive health in adolescents with anorexia nervosa

Anorexia nervosa (AN) initiates an adaptive response at the level of the hypothalamus, which results in a complex interplay involving most elements of the neuroendocrine axis. Consequences of onset of disease in adolescence include amenorrhoea, pubertal arrest with potential loss of target height, and osteoporosis with reduced capacity for future attainment of peak bone mass. With recovery, delay in restoration of menses is common. Hormonal therapies for restoration of bone mineral density (BMD) in adolescents have shown limited efficacy. This review will discuss the reproductive endocrine effects of AN in adolescence, and discuss new investigative tools for monitoring restoration of reproductive function and BMD in this population.

Peripheral quantitative computed tomography in children and adolescents: the 2007 ISCD Pediatric Official Positions

Peripheral quantitative computed tomography (pQCT) has mainly been used as a research tool in children. To evaluate the clinical utility of pQCT and formulate recommendations for its use in children, the International Society of Clinical Densitometry (ISCD) convened a task force to review the literature and propose areas of consensus and future research. The types of pQCT technology available, the clinical application of pQCT for bone health assessment in children, the important elements to be included in a pQCT report, and quality control monitoring techniques were evaluated. The review revealed a lack of standardization of pQCT techniques, and a paucity of data regarding differences between pQCT manufacturers, models and software versions and their impact in pediatric assessment. Measurement sites varied across studies. Adequate reference data, a critical element for interpretation of pQCT results, were entirely lacking, although some comparative data on healthy children were available. The elements of the pQCT clinical report and quality control procedures are similar to those recommended for dual-energy X-ray absorptiometry. Future research is needed to establish evidence-based criteria for the selection of the measurement site, scan acquisition and analysis parameters, and outcome measures. Reference data that sufficiently characterize the normal range of variability in the population also need to be established.

Sexual dimorphism in cortisol secretion starts after age 10 in healthy children: urinary cortisol metabolite excretion rates during growth

Detailed data on the physiological pattern of adrenocortical activity during normal growth are lacking. An established method to determine adrenocortical glucocorticoid secretion is the measurement of 24-h excretion rates of major urinary cortisol metabolites (C21). To test the hypothesis that the frequently reported higher cortisol secretion in men than in women develops during puberty, we examined C21 together with excretions of combined urinary free and conjugated cortisol (F(comb)) in 400 healthy boys and girls aged 3-18 yr using GC-MS. Daily excretion rates of C21, F(comb), and body surface area (BSA)-corrected F(comb) significantly increased with age in both sexes. In contrast, C21/BSA (microgxm(-2).day(-1)) declined from the age of 3-4 yr to 7-8 yr in boys and girls (P < 0.01; e.g., in boys: from 3,991 +/- 1,167 to 3,193 +/- 804), then increased in both sexes, and finally became discordant after the age of 11-12 yr with a further rise in males only (17- to 18-yr-olds: boys, 5,275 +/- 1,414; girls 3,939 +/- 1,586, P < 0.01). This pattern was associated with the occurrence of a lower index for 5alpha-reductase activity (allotetrahydrocortisol/tetrahydrocortisol) in females compared with males. Our results demonstrate dynamic changes in adrenocortical activity in healthy children resulting in an emerging sexual dimorphism in cortisol secretion after age 11. The latter can be explained, at least partly, by diverging 5alpha-reductase activities in boys and girls. F(comb), a frequently analyzed GC-MS parameter, proved not to reflect dynamic changes in cortisol secretion. In conclusion, the varying metabolic need for cortisol during normal growth may have implications for future improvements in glucocorticoid replacement therapy.

Adrenarche and the evolution of human life history

Adrenarche, the prepubertal onset of adrenal production of dehydroepiandrosterone sulfate (DHEAS), is a distinctive aspect of the human life course. Yet its evolutionary origins remain unexplained. Production of DHEAS is associated with the development of the zona reticularis, a novel histological layer within the adrenal gland, derived from the fetal adrenal gland, and associated with primates more generally. Evidence that DHEAS is a neurosteroid, together with the fact that increases in DHEAS parallel patterns of cortical maturation from approximately age 6 years to the mid-20s, suggests that DHEAS may play an important role in extended brain maturation among humans. DHEAS has demonstrated effects on mood in humans, and acts at neuron receptor sites. I suggest three ways in which DHEAS may play a role in human brain maturation: 1) increasing activity of the amgydala; 2) increasing activity of the hippocampus; and 3) promoting synaptogenesis within the cortex. I propose that associated changes in fearfulness and anxiety, and memory, could act to increase social interaction with nonfamiliar individuals and shape cognitive development. Comparison with the African apes suggests that the timing of adrenarche in chimpanzees may be similar to that in humans, though the full course of age-related changes in DHEAS and their relationship to reproductive and brain maturation are not clear. The role of DHEAS as a physiological mechanism supporting increased brain development, extended life span, and decreased sexual dimorphism is most compatible with Kaplan et al.'s (2000) theory of the evolution of human life history and intergenerational transfers.

Exaggerated adrenarche and altered cortisol metabolism in Type 1 diabetic children

Reported literature data strongly suggest that steroid metabolism is dysregulated in Type 1 diabetes mellitus. The aim of this study was to non-invasively examine the cortisol metabolism in children with Type 1 diabetes mellitus (T1DM) in detail and to test the hypothesis that adrenarche is affected under conventional intensive insulin therapy. In 24-h urine samples of 109 patients aged 4-18 years with T1DM of more than 1 year, steroids were profiled using gas chromatography-mass spectrometry. Additionally, urinary free cortisol (UFF) and cortisone (UFE) were quantified by RIA after extraction and chromatographic purification. Data on urinary steroids from 400 healthy controls served as reference values. Enzyme activities were assessed by established steroid metabolite ratios, e.g. 5alpha-reductase and 11beta-hydroxysteroid dehydrogenase Type 2 (11beta-HSD2) by 5alpha-tetrahydrocortisol/tetrahydrocortisol and UFE/UFF, respectively. Urinary markers of adrenarche, especially dehydroepiandrosterone and its direct metabolites were elevated in patients, as were urinary 6beta-hydroxycortisol, UFE, and 11beta-HSD2 activity. However, overall cortisol secretion, as reflected by the sum of major urinary cortisol metabolites, was mostly normal and activity of 5alpha-reductase clearly reduced. Our study provides evidence for an exaggerated adrenarche in T1DM children, which may help to understand reported sequelae in female patients like hyperandrogenic symptoms. The findings also suggest a reduced cortisol inactivation via 5alpha-reductase that is not compensated by a fall in cortisol secretion. Whether the elevated urinary 6beta-hydroxycortisol and cortisone excretion, observed in the patients, are also present in other forms of hypercortisolism and may thus serve as non-invasive clinical stress markers deserves further study.

Long-term protein intake and dietary potential renal acid load are associated with bone modeling and remodeling at the proximal radius in healthy children

BACKGROUND

Protein and alkalizing minerals are increasingly described as playing a major role in influencing bone status, not only in the elderly but also in children and adolescents.

OBJECTIVE

We examined whether the long-term dietary protein intake and diet net acid load are associated with bone status in children.

DESIGN

In a prospective study design in 229 healthy children and adolescents aged 6-18 y, long-term dietary intakes were calculated from 3-d weighed dietary records that were collected yearly over the 4-y period before a one-time bone analysis. Dietary acid load was characterized as potential renal acid load (PRAL) by using an algorithm including dietary protein, phosphorus, magnesium, and potassium. Proximal forearm bone variables were measured by peripheral quantitative computed tomography.

RESULTS

After adjustment for age, sex, and energy intake and control for forearm muscularity, BMI, growth velocity, and pubertal development, we observed that long-term dietary protein intake was significantly positively associated with periosteal circumference (P < 0.01), which reflected bone modeling, and with cortical area (P < 0.001), bone mineral content (P < 0.01), and polar strength strain index (P < 0.0001), which reflected a combination of modeling and remodeling. Children with a higher dietary PRAL had significantly less cortical area (P < 0.05) and bone mineral content (P < 0.01). Long-term calcium intake had no significant effect on any bone variable.

CONCLUSIONS

Long-term dietary protein intake appears to act anabolically on diaphyseal bone strength during growth, and this may be negated, at least partly, if dietary PRAL is high, ie, if the intake of alkalizing minerals is low.

Growth patterns at distal radius and tibial shaft in pubertal girls: a 2-year longitudinal study

Bone changes, in terms of both size and BMD, were assessed longitudinally in pubertal girls. Before puberty, BMD at the distal radius declined, whereas bone size increased, suggesting that normal growing girls experience a transient period of increased bone fragility. This could explain the elevated low-trauma forearm fracture rates reported in earlier studies.

INTRODUCTION

Longitudinal data on bone growth during puberty are sparse. Such information is needed to understand the sequence of biological changes, the physical and mechanical consequences for the growing skeleton, and the implications for later life.

MATERIALS AND METHODS

The geometric properties and volumetric BMD (vBMD) of the distal radius and tibial shaft were measured using pQCT in 258 pubertal girls followed over 2 years. A new hierarchical linear statistical modeling approach was used to determine true longitudinal trends.

RESULTS

The growth rates of cross-sectional area (CSA) and BMC of the distal radius peaked at 16 and 9 months before menarche, respectively. This growth asynchrony between bone size and mass meant that total vBMD of the distal radius declined until 1 year before menarche. At the tibial shaft, total vBMD and cortical vBMD increased monotonically without any such transient reduction. Cortical thickness increased linearly, which was accounted for mainly by bone formation at the periosteal surface before menarche, but by both periosteal and endocortical apposition after menarche. During puberty, the ratio of cortical-to-total CSA of the tibial shaft increased and that of marrow-to-total CSA decreased.

CONCLUSIONS

The temporal pattern of bone growth during puberty differs at the distal radius and tibial shaft. A transient decrease in vBMD, arising from asynchronous bone size and mass growth, occurs only at the radius. In the tibia, the mechanism of cortical thickening changes from periosteal apposition premenarche to both periosteal and endocortical apposition postmenarche.

Bone mass acquisition in healthy children

Although 80% of the variance in bone mass is determined genetically, there are many other factors which influence the accumulation of bone in early life and affect future risks of osteoporosis. This review considers the genetic, fetal, and environmental influences on bone mass acquisition in healthy children, and highlights important areas where paediatricians may have a role by counselling children and their families to adopt a healthy lifestyle which promotes bone health.

Adrenal Steroid Hormones and Metaphyseal Bone in Children

BACKGROUND/OBJECTIVES

The responses of metaphyseal bone tissue to physiological variations of endogenous adrenal steroid hormones during childhood are unclear. Therefore, we studied potential hormonal influences in children before the appearance of pubic hair (onset of pubarche).

METHODS

Excretions of major glucocorticoid metabolites (C21), cortisol, sum of adrenarchal dehydroepiandrosterone and its immediate 16-hydroxylated metabolites (DHEA&M), and 5-androstene-3beta,17beta-diol (hermaphrodiol) were analyzed in a cross-sectional study in 24-hour urine samples of 109 healthy boys and girls, aged 6-13 years, using steroid profiling by gas chromatography-mass spectrometry. Total and trabecular volumetric bone mineral densities, bone mineral content (BMC) and bone strength strain index were determined with peripheral quantitative computed tomography at the distal forearm.

RESULTS

In multiple regression analyses significant associations with the metaphyseal radius were seen for grip force, age, or BMI depending on gender and bone variable analyzed. DHEA&M did not contribute to the explanation of the variance of any bone variable. However, hermaphrodiol positively explained a significant part of variation of bone mineral densities, and BMC (p < 0.01) in girls. Significantly negative associations with all bone variables were seen in boys for cortisol.

CONCLUSIONS

The steroid hormones, cortisol and hermaphrodiol, in their physiological ranges, but not the adrenarche marker DHEA&M, appear to associate with metaphyseal bone in a sex-dependent manner during childhood.