Metacarpal thickness, width, length and medullary diameter in children--reference curves from the First Zürich Longitudinal Study

Adaptation and validation of an artificial intelligence based digital radiogrammetry tool for assessing bone health of indian children and youth with type-1 diabetes

BACKGROUND AND OBJECTIVES

BoneXpert (BX) is an artificial intelligence software used primarily for bone age assessment. Besides, it can also be used to screen for bone health using the digital radiogrammetry tool called bone health index (BHI) for which normative reference values available are calculated from healthy European children. Due to ethnic difference in bone geometry, in a previous study, we generated reference curves based on healthy Indian children. The objectives of this study were: 1) To assess and compare bone health of Indian children with Type 1 diabetes (T1D) using both European and Indian BHI SDS reference data and 2) To identify determinants of poor bone health in Indian children and youth with T1D by using BHI tool (based on BHI-SDS Indian reference data) of BX.

METHOD

The BHI was assessed retrospectively in 1159 subjects with T1D using digitalised left-hand x-rays and SDS were computed using European and Indian data. The demographic, anthropometric, clinical, biochemistry, dual x-ray absorptiometry (DXA) data and peripheral quantitative computed tomography (pQCT) data collection were performed using standard protocols and were extracted from hospital records.

RESULTS

The BHI correlated well with DXA and pQCT parameters in subjects with T1D. BHI-SDS calculated using Indian reference data had better correlation with height and DXA parameters. 8.6% study participants had low (less than -2) BHI-SDS (Indian), with height SDS having significant effect. Subjects with low BHI-SDS were older, shorter and had higher duration of diabetes. They also had lower IGF1 and vitamin D concentrations, bone mineral density, and trabecular density. Female gender, increased duration of illness, poor glycaemic control, and vitamin D deficiency/insufficiency were significant predictors of poor BHI-SDS.

CONCLUSION

Our study highlights the utility of digital radiogrammetry AI tool to screen for bone health of children with T1D and demonstrates and highlights the necessity of interpretation using ethnicity specific normative data.

Does ethnicity influence bone health index in children? A pilot study

BACKGROUND

Several pathological conditions can lead to variations in bone mineral content during growth. When assessing bone age, bone mineral content can be estimated without supplementary cost and irradiation. Manual assessment of bone quality using the Exton-Smith index (ESI) and automated assessment of the bone health index (BHI) provided by the BoneXpert® software are available but still not validated in different ethnic groups.

OBJECTIVE

Our aim is to provide normative values of the ESI and BHI for healthy European Caucasian and first-generation children of North Africans living in Europe.

MATERIALS AND METHODS

A sex- and aged-match population of 214 girls (107 European-Caucasian and 107 North African) and 220 boys (111 European-Caucasian and 109 North African) were retrospectively and consecutively included in the study. Normal radiographs of the left hand and wrist from healthy children were retrieved from those performed in a single institution from 2008 to 2017 to rule out a left-hand fracture. Radiographs were processed by BoneXpert® to obtain the BHI and BHI standard deviation score (SDS). One radiologist, blinded to BHI values, manually calculated ESI for each patient. The variability for both methods was assessed and compared using the standard deviation (SD) of the median (%) for each class of age and sex, and ESI and BHI trends were compared by sex and ethnic group.

RESULTS

The final population comprised 434 children ages 3 to 15 years (214 girls). Overall, BHI was lower in North African children (mean = 4.23 for girls and 4.17 in boys) than in European Caucasians (mean = 4.50 for girls and 4.68 in boys) (P < 0.001). Regardless of ethnicity, 29 girls (13.6%) and 34 boys (15.5%) had BHI more than 2 SD from the mean. While correlated to BHI, ESI has a higher variability than BHI and is more pronounced from 8-12 years for both sexes (mean ESI in European Caucasian girls and boys 17.47 and 20.87, respectively) (P < 0.001). ESI showed more than 15% variability in European girls from 8-12 years and a plateau in North African boys from 12 years to 16 years. However, the BHI has less than 15% variability regardless of age and ethnic group.

CONCLUSION

BHI may be a reliable tool to detect children with abnormal bone mineral content, with lower variability compared to ESI and with specific trends depending on sex and ethnicity.

Online software Boneureka assessing bone age based on metacarpal length in healthy children: proof-of-concept study

BACKGROUND

Bone age in children is mainly assessed using the Greulich and Pyle (GP) atlas, a validated method with limited interobserver accuracy. While automated methods increase interobserver accuracy, they represent considerable costs and technical requirements.

OBJECTIVE

A proof-of-concept study to create and evaluate an online software program, Boneureka^©, based on linear metacarpal length measurements, to assess bone age in healthy children.

MATERIALS AND METHODS

The study retrospectively included 434 consecutive children (215 girls) who underwent a left-hand radiograph to rule out trauma between March 2008 and December 2017. Two reviewers measured the second to fourth metacarpal lengths on each radiograph and the distance between the centre of the epiphyses of the second and fifth metacarpals. A single reviewer estimated the bone age using the GP atlas. The automated software assessed the bone age for all radiographs. A mathematical model was developed based on linear regressions to provide the mean bone age and standard deviation based on the estimates. Pearson and intraclass correlation coefficient (ICC) were used to evaluate the correlation and agreement between the estimated bone ages using Boneureka^©, the GP atlas and BoneXpert^® compared to chronological age.

RESULTS

The measure that showed the highest correlation (r²=0.877 for girls and r²=0.834 for boys; P<.001) and the highest ICC (ICC=0.937 for girls and ICC=0.926 for boys; P<0.001) with chronological age was length of the second metacarpal. The GP atlas and the automated software evaluation had excellent ICC with chronological age (ICC>0.95 for both methods and sexes). Using this data, we created an online software program based on the second metacarpal length to obtain bone age estimates, means and standard deviations.

CONCLUSION

The newly created online software Boneureka,^© based on the second metacarpal length, is a reliable and user-friendly tool to assess bone age in healthy children. Further studies on a larger population should be performed to validate the developed reference values.

Role of sex steroids hormones in the regulation of bone metabolism in men: Evidence from clinical studies

Sex steroids regulate bone metabolism in young men during growth and consolidation. Their deficit during growth compromises longitudinal and radial growth of bones and has a negative impact on body height, bone width, peak areal bone mineral density (aBMD) and bone microarchitecture. In older men, the deficit of sex steroid hormones (mainly 17β-oestradiol) contributes to high bone turnover rate, low aBMD, poor bone microarchitecture, low estimated bone strength, accelerated bone loss and rapid decline of bone microarchitecture. The role of 17β-oestradiol is confirmed by the case of men with congenital oestrogen receptor deficit and with congenital aromatase deficiency. 17β-oestradiol inhibits bone resoption, whereas both hormones regulate bone formation. However, the associations are weak. Prospective data on the utility of blood 17β-oestradiol or testosterone for fracture risk assessment are inconsistent. Men with hypogonadism have decreased aBMD and poor bone microarchitecture. In men with hypogonadism, testosterone replacement therapy increases aBMD and improves bone microarchitecture. In men with prostate cancer, androgen deprivation therapy (gonadoliberin analogues) induces rapid bone loss and severe deterioration of bone microarchitecture.

Feline Skeletal Reference Guide: A Cadaveric Radiographic Measurement on Lower Limb Extremities

OBJECTIVE

 The aim of this study was to create a feline reference database for the length, width and slenderness (length to width ratio) of metacarpal and metatarsal bones, radius and tibia.

STUDY DESIGN

 Radiographs of the radius, tibia, metacarpus and metatarsus were performed in domestic short hair cat cadavers (n = 40). Length and width of the aforementioned bones were measured in mature domestic shorthair cats and bone slenderness (length/width) and index ratios calculated.

RESULTS

 A significant skeletal sex dimorphism exists in cats, with bones of the metacarpus, metatarsus, radius and tibia generally longer and wider in male cats compared with female cats, with differences frequently significant. The most significant difference was identified for the width of Mc5 (p = 0.0008) and the length and width of Mt5 (p = 0.0005). Index ratios for length and width of radius to metacarpal bones, and tibia to metatarsal bones, were not significantly different between male and female cats, except for Mc5. The index ratio for Mc5 was significantly higher in male cats (p = 0.002).

CONCLUSION

 The present study provides insights into the normal length and width of distal forelimb and hind limb bones as well as bone index ratios in mature domestic shorthair cats. Using this information, it is now possible to quantitatively assess the relationship between these bones in domestic cats using radiography. This will assist not only with the diagnosis and categorization of skeletal abnormalities but can also guide surgical interventions of metacarpal and metatarsal bone fractures.

Cortical Bone Mass is Low in Boys with Klinefelter Syndrome and Improves with Oxandrolone

Context

Klinefelter syndrome (KS) is the most common sex aneuploidy in men. Affected males have hypogonadism, and, as a result, face an increased risk for osteoporosis and fractures. Androgen therapy is standard in adolescents and adults with KS but has not been used earlier in childhood.

Objective

To determine the effects of androgen treatment on bone mass in children with KS.

Methods

Randomized, double-blind, placebo-controlled clinical trial of oxandrolone (OX; 0.06 mg/kg daily; n = 38) versus placebo (PL; n = 40) for 2 years in boys with KS (ages 4-12 years). Changes in bone mass were examined by digital x-ray radiogrammetry, which determines the Bone Health Index (BHI) and standard deviation score (SDS).

Results

BHI SDS was similar between groups at baseline (–0.46 ± 1.1 vs –0.34 ± 1.0 OX vs PL, P > .05) and higher in the OX group at 2 years (–0.1 ± 1.3 vs –0.53 ± 0.9, OX vs PL, P < .01). At baseline, BHI SDS values of all subjects were not normally distributed with 25.7% of subjects plotted below –1 SDS (P < .001), suggesting a deficit in bone mass. In total, 13.5% of subjects had sustained a fracture and their BHI SDS was lower than those with no fractures (–1.6 ± 1.3 vs –0.3 ± 1.0, P = .004).

Conclusion

Bone mass using BHI SDS is reduced in some children with KS and improves with OX. Since these individuals are at risk for osteoporosis, age-appropriate androgen replacement and future studies on bone health in children with KS should be further explored.

Revisiting the radiographic assessment of osteoporosis-Osteopenia in children 0-2 years of age. A systematic review

BACKGROUND

Imaging for osteoporosis has two major aims, first, to identify the presence of low bone mass (osteopenia), and second, to quantify bone mass using semiquantitative (conventional radiography) or quantitative (densitometry) methods. In young children, densitometry is hampered by the lack of reference values, and high-quality radiographs still play a role although the evaluation of osteopenia as a marker for osteoporosis is subjective and based on personal experience. Medical experts questioned in court over child abuse, often refer to the literature and state that 20-40% loss of bone mass is warranted before osteopenia becomes evident on radiographs. In our systematic review, we aimed at identifying evidence underpinning this statement. A secondary outcome was identifying normal references for cortical thickness of the skeleton in infants born term, < 2 years of age.

METHODS

We undertook systematic searches in Medline, Embase and Svemed+, covering 1946-2020. Unpublished material was searched in Clinical trials and International Clinical Trials Registry Platform (ICTRP). Both relevant subject headings and free text words were used for the following concepts: osteoporosis or osteopenia, radiography, children up to 6 years.

RESULTS

A total 5592 publications were identified, of which none met the inclusion criteria for the primary outcome; the degree of bone loss warranted before osteopenia becomes visible radiographically. As for the secondary outcome, 21 studies were identified. None of the studies was true population based and none covered the pre-defined age range from 0-2 years. However, four studies of which three having a crossectional and one a longitudinal design, included newborns while one study included children 0-2 years.

CONCLUSIONS

Despite an extensive literature search, we did not find any studies supporting the assumption that a 20-40% bone loss is required before osteopenia becomes visible on radiographs. Reference values for cortical thickness were sparse. Further studies addressing this important topic are warranted.

Plasticity in the growth of body segments in relation to height-for-age and maternal education in Guatemala

Objectives

Plasticity in the growth of body segments between populations has been researched in relation to migration, temporal change and high‐altitude studies. We study the within population variation in body segments, thus controlling for some of the environmental and genetic differences that could be at play in between populations studies. We test a version of the thrifty phenotype hypothesis, where the growth of head‐trunk and hand are prioritized due to their functional significance over height and leg growth.

Materials and methods

A total of 3913 Guatemalan, rural, semi‐urban and urban, Maya and Ladino children 6 to 15 years old were studied. Height, sitting height, leg length, and metacarpal length were studied in relation to three proxies for living conditions: height‐ and leg length‐for‐age, and maternal education. Estimation statistics and null hypothesis significance testing were used to analyze the data.

Results

Metatarsal length and sitting height values were higher than height and leg length respectively. Relative metacarpal length was conserved across height‐for‐age groups. Females were less affected than males for metacarpal length and sitting height, but more affected for leg length.

Conclusion

Our results agree with the thrifty phenotype hypothesis, where metacarpal and sitting height growth would be prioritized over height and leg length due to greater functional significance.

Applicability of two commonly used bone age assessment methods to twenty-first century UK children

Objectives

To assess the effect of secular change on skeletal maturation and thus on the applicability of the Greulich and Pyle (G&P) and Tanner and Whitehouse (TW3) methods.

Methods

BoneXpert was used to assess bone age from 392 hand trauma radiographs (206 males, 257 left). The paired sample t test was performed to assess the difference between mean bone age (BA) and mean chronological age (CA). ANOVA was used to assess the differences between groups based on socioeconomic status (taken from the Index of Multiple Deprivation).

Results

CA ranged from 2 to 15 years for females and 2.5 to 15 years for males. Numbers of children living in low, average and high socioeconomic areas were 216 (55%), 74 (19%) and 102 (26%) respectively. We found no statistically significant difference between BA and CA when using G&P. However, using TW3, CA was underestimated in females beyond the age of 3 years, with significant differences between BA and CA (− 0.43 years, SD 1.05, p = < 0.001) but not in males (0.01 years, SD 0.97, p = 0.76). Of the difference in females, 17.8% was accounted for by socioeconomic status.

Conclusion

No significant difference exists between BoneXpert-derived BA and CA when using the G&P atlas in our study population. There was a statistically significant underestimation of BoneXpert-derived BA compared with CA in females when using TW3, particularly in those from low and average socioeconomic backgrounds. Secular change has not led to significant advancement in skeletal maturation within our study population.

Key Points

• The Greulich and Pyle method can be applied to the present-day United Kingdom (UK) population.

• The Tanner and Whitehouse (TW3) method consistently underestimates the age of twenty-first century UK females by an average of 5 months.

• Secular change has not advanced skeletal maturity of present-day UK children compared with those of the mid-twentieth century.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06300-x) contains supplementary material, which is available to authorized users.

A longitudinal comparison of appendicular bone growth and markers of strength through adolescence in a South African cohort using radiogrammetry and pQCT

To compare growth patterns and strength of weight- and non-weight-bearing bones longitudinally. Irrespective of sex and ethnicity, metacarpal growth was similar to that of the non-weight-bearing radius but differed from that of the weight-bearing tibia. Weight- and non-weight-bearing bones have different growth and strength patterns.

INTRODUCTION

Functional loading modulates bone size and strength.

METHODS

To compare growth patterns and strength of weight- and non-weight-bearing bones longitudinally, we performed manual radiogrammetry of the second metacarpal on hand-wrist radiographs and measured peripheral quantitative computed tomography images of the radius (65%) and tibia (38% and 65%), annually on 372 black and 152 white South African participants (ages 12-20 years). We aligned participants by age from peak metacarpal length velocity. We assessed bone width (BW, mm); cortical thickness (CT, mm); medullary width (MW, mm); stress-strain index (SSI, mm³); and muscle cross-sectional area (MCSA, mm²).

RESULTS

From 12 to 20 years, the associations between metacarpal measures (BW, CT and SSI) and MCSA at the radius (males R² = 0.33-0.45; females R² = 0.12-0.20) were stronger than the tibia (males R² = 0.01-0.11; females R² = 0.007-0.04). In all groups, radial BW, CT and MW accrual rates were similar to those of the metacarpal, except in white females who had lower radial CT (0.04 mm/year) and greater radial MW (0.06 mm/year) accrual. In all groups, except for CT in white males, tibial BW and CT accrual rates were greater than at the metacarpal. Tibial MW (0.29-0.35 mm/year) increased significantly relative to metacarpal MW (- 0.07 to 0.06 mm/year) in males only. In all groups, except white females, SSI increased in each bone.

CONCLUSION

Irrespective of sex and ethnicity, metacarpal growth was similar to that of the non-weight-bearing radius but differed from that of the weight-bearing tibia. The local and systemic factors influencing site-specific differences require further investigation. Graphical abstract.

Metacarpal Growth During Adolescence in a Longitudinal South African Cohort

To monitor the drift of the periosteal and endocortical surfaces during metacarpal growth longitudinally, radiogrammetry was carried out on hand-wrist X-rays of 572 children from the Birth to Twenty Bone Health Cohort annually from ages 9 to 21 years. This is the largest collection of longitudinal X-rays in African children. The second metacarpal bone length, bone width, and medullary width were measured using digital vernier calipers on a total of 4730 X-rays. Superimposition by Translation and Rotation (SITAR) was used to obtain age at peak metacarpal length velocity (PLV). Bone width and medullary width were modeled using SITAR against both chronological age and age from PLV. In black and white females, tempo and velocity of metacarpal length growth was synchronized. Black males, however, attained PLV 7 months later than white males (p < 0.0001). Compared to white males, black males had a longer second metacarpal (p < 0.05), and greater bone width size (p < 0.02), tempo (p < 0.0009), and velocity (p < 0.0001). Medullary width growth velocity in black participants peaked 2 years prior to attainment of PLV and exceeded that of their white peers (p < 0.0001) in whom it peaked 6 to 12 months post-PLV attainment. Black adolescents therefore had wider bones with relatively thinner cortices and wider medullary cavities than their white peers. Ethnic and sex differences also occurred in the timing of medullary width contraction that accompanied expansion in bone width and cortical thickness. In black males, medullary width contraction commenced approximately 3 years later than in black females, whereas in white males this occurred a year later than in white females. The ethnic and sex differences in bone acquisition reported in this study may differentially affect bone mass in later life. © 2017 American Society for Bone and Mineral Research.

Prevalence of SHOX haploinsufficiency among short statured children

BACKGROUND

The aim of this clinical study was to determine the prevalence of SHOX haploinsufficiency in a population of short stature patients and describe their anthropometric measurements.

METHODS

574 short statured patients were evaluated in a single center (1992-2015). SHOX copy number was detected by quantitative polymerase chain reaction (qPCR) in 574 subjects, followed by multiplex ligation-dependent probe amplification (MLPA) and DNA sequencing in subjects with SHOX haploinsufficiency. We evaluated anthropometric measurements at birth, and at first examination. Skeletal abnormalities were recorded for patients with SHOX haploinsufficiency.

RESULTS

Thirty-two patients were excluded due to Turner syndrome (n = 28), SRY-positive 46,XX male karyotype (n = 1), or lacked clinical follow-up information (n = 3). The prevalence of SHOX haploinsufficiency was 9 out of 542 (1.7%). The nine children had decreased height -2.85 (0.6) SD scores (SDS) (mean (SD)) and weight -2.15 (1.36) SDS, P < 0.001 and P = 0.001, respectively. The sitting height/height ratio was increased, P = 0.04. Madelung deformity was diagnosed in three patients. Mean height was -2.9 (0.4) SDS at baseline and increased by 0.25 (0.2) SDS, P = 0.046, after 1 y of growth hormone (GH) treatment.

CONCLUSION

The prevalence of SHOX haploinsufficiency was 1.7%. The clinical findings indicating SHOX haploinsufficiency among the nine children were disproportionate short stature and forearm anomalies.

A new implementation of digital X-ray radiogrammetry and reference curves of four indices of cortical bone for healthy European adults

Digital X-ray radiogrammetry performs measurements on a hand radiograph in digital form. We present an improved implementation of the method and provide reference curves for four indices for the amount of bone. We collected 1662 hand radiographs of healthy subjects of age 9-100 years.

PURPOSE

The digital X-ray radiogrammetry (DXR) method has been shown to be efficient for diagnosis of osteoporosis and for assessment of progression of rheumatoid arthritis. The aim of this work is to present a new DXR implementation and reference curves of four indices of cortical bone and to compare their relative SDs in healthy subjects at fixed age and gender.

MATERIALS AND METHODS

A total of 1662 hand radiographs of healthy subjects of age 9-100 years were collected in Jena in 2001-2005. We also used a longitudinal study of 116 Danish children born in 1952 with on average 11 images taken over the age range 7 to 40 years. The new DXR method reconstructs the whole metacarpal contour so that the metacarpal lengths can be measured and used in two of the indices. The new DXR method automatically validates 97 % of the images and is implemented as a local server for PACS users.

RESULTS

The Danish bone health index (BHI) data are consistent with the Jena data and also with the published BHI reference for healthy children. BHI is found to have smaller relative SD than the other three indices in the Jena cohort over the age range 20-80 years.

CONCLUSION

The new DXR method is an extension of the existing BoneXpert method for children, which allows patients to be followed from childhood into adulthood with the same method. By making all four indices of cortical bone available within the same medical device, it becomes possible to decide which index has the best relation to fracture risk in future studies.

Reference values for digital X-ray radiogrammetry parameters in children and adolescents in comparison to estimates in patients with distal radius fractures

The first objective of this study was to determine normative digital X-ray radiogrammetry (DXR) values, based on original digital images, in a pediatric population (aged 6-18 years). The second aim was to compare these reference data with patients suffering from distal radius fractures, whereas both cohorts originated from the same geographical region and were evaluated using the same technical parameters as well as inclusion and exclusion criteria. DXR-BMD and DXR-MCI of the metacarpal bones II-IV were assessed on standardized digital hand radiographs, without printing or scanning procedures. DXR parameters were estimated separately by gender and among six age groups; values in the fracture group were compared to age- and gender-matched normative data using Student's t tests and Z scores. In the reference cohort (150 boys, 138 girls), gender differences were found in bone mineral density (DXR-BMD), with higher values for girls from 11 to 14 years and for boys from 15 to 18 years (p < 0.05). Girls had higher normative metacarpal index (DXR-MCI) values than boys, with significant differences at 11-14 years (p < 0.05). In the case-control investigation, the fracture group (95 boys, 69 girls) presented lower DXR-BMD at 15-18 years in boys and 13-16 years in girls vs. the reference cohort (p < 0.05); DXR-MCI was lower at 11-18 years in boys and 11-16 years in girls (p < 0.05). Mean Z scores in the fracture group for DXR-BMD were -0.42 (boys) and -0.46 (girls), and for DXR-MCI were -0.51 (boys) and -0.53 (girls). These findings indicate that the fully digital DXR technique can be accurately applied in pediatric populations ≥ 6 years of age. The lower DXR-BMD and DXR-MCI values in the fracture group suggest promising early identification of individuals with increased fracture risk, without the need for additional radiation exposure, enabling the initiation of prevention strategies to possibly reduce the incidence of osteoporosis later in life.

ENDOCRINOLOGY AND ADOLESCENCE: Osteoporosis in children: diagnosis and management

Osteoporosis in children can be primary or secondary due to chronic disease. Awareness among paediatricians is vital to identify patients at risk of developing osteoporosis. Previous fractures and backaches are clinical predictors, and low cortical thickness and low bone density are radiological predictors of fractures. Osteogenesis Imperfecta (OI) is a rare disease and should be managed in tertiary paediatric units with the necessary multidisciplinary expertise. Modern OI management focuses on functional outcomes rather than just improving bone mineral density. While therapy for OI has improved tremendously over the last few decades, this chronic genetic condition has some unpreventable, poorly treatable and disabling complications. In children at risk of secondary osteoporosis, a high degree of suspicion needs to be exercised. In affected children, further weakening of bone should be avoided by minimising exposure to osteotoxic medication and optimising nutrition including calcium and vitamin D. Early intervention is paramount. However, it is important to identify patient groups in whom spontaneous vertebral reshaping and resolution of symptoms occur to avoid unnecessary treatment. Bisphosphonate therapy remains the pharmacological treatment of choice in both primary and secondary osteoporosis in children, despite limited evidence for its use in the latter. The duration and intensity of treatment remain a concern for long-term safety. Various new potent antiresorptive agents are being studied, but more urgently required are studies using anabolic medications that stimulate bone formation. More research is required to bridge the gaps in the evidence for management of paediatric osteoporosis.

Sex difference in age and performance in elite Swiss freestyle swimmers competing from 50 m to 1,500 m

Recent studies reported different ages for peak freestyle swimming performances for 50 m and 1,500 m. The aims of the present study were (i) to determine the age of peak freestyle swimming speed for distances including 50 m, 100 m, 200 m, 400 m, 800 m, and 1,500 m and to (ii) analyze the sex difference in peak freestyle swimming speed for all distances between 50 m and 1,500 m for elite female and male swimmers competing at national level. Data from the ‘Swiss Swimming Federation’ between 2006 and 2010 from 10,405 men and 9,552 women were analyzed using regression analyses and analyses of variance (ANOVA). Women achieved peak freestyle swimming speed at ~20–21 years from 50 m to 400 m, at ~24–25 years in 1,500 m and at ~25–27 years in 800 m. In men, the age of peak freestyle swimming speed varied between ~22–23 years and ~25–27 years for 50 m to 1,500 m. Between the age of 10 and 29 years, the sex difference in freestyle swimming speed increased from 2.2 ± 0.4% to 19.0 ± 6.7% in 50 m (r² = 0.87, P < 0.001), from 2.4 ± 0.7% to 10.8 ± 2.8% in 100 m (r² = 0.67, P = 0.004) and from 3.6 ± 1.9% to 10.2 ± 3.4% in 200 m (r² = 0.60, P = 0.008). In 400 m (r² = 0.24), 800 m (r² = 0.39) and 1,500 m (r² = 0.34), the sex difference showed no changes (P > 0.05) with 6.9 ± 3.0%, 5.8 ± 3.5%, and 9.7 ± 8.6%, respectively. The sex difference in freestyle swimming speed showed no change with increasing race distance (r² = 0.12, P > 0.05). To summarize, the age of peak freestyle swimming speed increased for women with the length of the race distance from 50 m to 200 m, but not from 400 m to 1,500 m. For men, the age of peak freestyle swimming speed varied between ~22–23 years and ~25–27 years from 50 m to 1,500 m. The sex difference in freestyle swimming speed of 9.1 ± 2.5% showed no change with increasing race distance. Future studies need to confirm these findings in elite swimmers competing at international level such as the World Championships and the Olympic Games.

IGFALS gene dosage effects on serum IGF-I and glucose metabolism, body composition, bone growth in length and width, and the pharmacokinetics of recombinant human IGF-I administration

CONTEXT

Acid labile subunit (ALS) deficiency, caused by IGFALS mutations, is a subtype of primary IGF-I deficiency (PIGFD) and has been associated with insulin resistance (IR) and osteopenia. Whether patients respond to recombinant human IGF-I (rhIGF-I) is unknown.

OBJECTIVE AND DESIGN

This study determined the 14-hour pharmacokinetic response of free and total IGF-I and IGF binding protein 3 (IGFBP-3) to a single sc dose of rhIGF-I (120 μg/kg) in four ALS-deficient patients, compared with severe PIGFD, moderate PIGFD, and controls. Intravenous glucose tolerance tests, fasting blood levels, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and metacarpal radiogrammetry were performed in the four patients and 12 heterozygous family members.

RESULTS

IGF-I and IGFBP-3 increased above baseline (P < .05) for 2.5 hours, returning to baseline 7 hours after rhIGF-I injection. Mean (SD) IGF-I Z-score increased by 2.49 (0.90), whereas IGFBP-3 Z-score increased by 0.57 (0.10) only. IGF-I elimination rates in ALS deficiency were similar, but the IGF-I increment was lower than those for severe PIGFD. Significant gene dosage effects were found for all IGF-I peptides, height, forearm muscle size, and metacarpal width. Bone analysis showed that ALS deficiency creates a phenotype of slender bones with normal size-corrected density. Abnormal glucose handling and IR was found in three of four patients and 6 of 12 carriers.

CONCLUSIONS

These gene dosage effects demonstrate that one functional IGFALS allele is insufficient to maintain normal ALS levels, endocrine IGF-I action, full growth potential, muscle size, and periosteal expansion. Similar gene dosage effects may exist for parameters of IR. Despite similar IGF-I elimination compared with severe PIGFD, ALS-deficient patients cannot mount a similar response. Alternative ways of rhIGF-I administration should be sought.

Sex-related differences and age of peak performance in breaststroke versus freestyle swimming

Background

Sex-related differences in performance and in age of peak performance have been reported for freestyle swimming. However, little is known about the sex-related differences in other swimming styles. The aim of the present study was to compare performance and age of peak performance for elite men and women swimmers in breaststroke versus freestyle.

Methods

Race results were analyzed for swimmers at national ranked in the Swiss high score list (during 2006 through 2010) and for international swimmers who qualified for the finals of the FINA World Swimming Championships (during 2003 through 2011).

Results

The sex-related difference in swimming speed was significantly greater for freestyle than for breaststroke over 50 m, 100 m, and 200 m race distances for Swiss swimmers, but not for FINA finalists. The sex-related difference for both freestyle and breaststroke swimming speeds decreased significantly with increasing swimming distance for both groups. Race distance did not affect the age of peak performance by women in breaststroke, but age of peak performance was four years older for FINA women than for Swiss women. Men achieved peak swimming performance in breaststroke at younger ages for longer race distances, and the age of peak swimming performance was six years older for FINA men than for Swiss men. In freestyle swimming, race distance did not affect the age of peak swimming performance for Swiss women, but the age of peak swimming performance decreased with increasing race distance for Swiss men and for both sexes at the FINA World Championships.

Conclusions

Results of the present study indicate that (i) sex-related differences in swimming speed were greater for freestyle than for breaststroke for swimmers at national level, but not for swimmers at international level, and (ii) both female and male swimmers achieved peak swimming speeds at younger ages in breaststroke than in freestyle. Further studies are required to better understand differences between trends at national and international levels.

The changes in age of peak swim speed for elite male and female Swiss freestyle swimmers between 1994 and 2012

This study determined the age and its changes across years of peak swimming performance from 50 to 1,500 m freestyle. Data of 70,059 Swiss freestyle swimmers (33,725 women and 36,334 men) aged 10-40 years and competing from 50 to 1,500 m were analysed. The association between age and swimming speed of the annual ten fastest swimmers was investigated using single and multi-level hierarchical regression analyses. For women, age of peak swimming speed increased in 50 m from 18.9 (s = 2.3) to 20.4 (s = 4.2) years but decreased in 1,500 m from 25.0 (s = 13.1) (1996) to 18.1 (s = 3.7) years. For 100-800 m, age remained at 19.1 (s = 1.1), 19.3 (s = 1.1), 18.7 (s = 1.5) and 18.5 (s = 1.3) years, respectively. For men, age of peak swimming speed decreased in 50 m from 23.0 (s = 4.0) to 23.0 (s = 3.5) but remained for 100-1,500 m at 22.5 (s = 1.4), 21.4 (s = 0.9), 20.3 (s = 0.9), 20.3 (s = 0.9) and 20.3 (s = 1.1) years, respectively. Age was positively associated with swimming speed for 50-800 m, but negatively for 1,500 m. In conclusion, the age of peak swimming speed was younger in women compared to men for 50-800 m freestyle. For women, age of peak swimming speed increased in 50 m but decreased in 1,500 m freestyle across years. For men, age of peak swimming speed decreased in 50 m freestyle.

Women achieve peak freestyle swim speed at earlier ages than men

Background

The age of peak swim performance has been investigated for freestyle swimmers for distances ranging from 50 m to 1500 m among swimmers aged 19 to 99 years. However, studies have yet to investigate the 10 to 19 year-old age group. The aims of the present study were (1) to investigate the age range of peak freestyle swim speed, and (2) to find differences in age range and peak freestyle swim speed between male and female freestyle swimmers from 50 m to 1500 m at a national level.

Methods

The changes in age range and peak freestyle swim speed among Swiss elite freestyle swimmers aged 0–9 years and 70–79 years who were ranked on the Swiss high score list between 2006 and 2010 were analyzed using linear regression analyses and analysis of variance.

Results

Men were fastest at ages 22–23 years for 100 m and 200 m; at ages 24–25 years for 400 m and 800 m; and at 26–27 years for 50 m and 1500 m. Women achieved peak freestyle swim speed at ages 20–21 years for all distances with the exception of 800 m. In the 800 m, women were fastest at ages 26–27 years. The difference in peak freestyle swim speed decreased with increasing swim distance from 50 m to 800 m (ie, 13.1% ± 1.3% in 50 m; 13.2% ± 0.9% in 100 m; 10.8% ± 0.9% in 200 m; 7.9% ± 1.3% in 400 m; and 4.2% ± 2.0% in 800 m). For 1500 m, however, the gender difference increased to 6.4% ± 2.3%.

Conclusion

These findings suggest that peak freestyle swim speed is achieved at lower age ranges in women when compared to men at 50 m to 1500 m, but not at 800 m. The gender difference in peak freestyle swim speed decreased with increasing swim distance from 50 m to 800 m, but not for 1500 m. These data should be confirmed with swimmers at an international level.

Comparison of radiogrammetrical metacarpal indices in children and reference data from the First Zurich Longitudinal Study

BACKGROUND

A number of radiogrammetrical metacarpal indices are in use, some of which have been adapted for children.

OBJECTIVE

The purpose of this study was to compare four known indices-bone mineral density (BMD), relative cortical area, Exton-Smith index, bending breaking resistance index-and the more recently defined pediatric bone index (PBI) according to the two criteria of minimum height dependence and minimum variability in children of equal bone age.

MATERIALS AND METHODS

A total of 3,121 left-hand radiographs from 231 healthy Caucasian children ranging in age from 3 to 19 years old were analysed using BoneXpert®, a programme for automatic analysis of hand radiographs and assessment of bone age.

RESULTS

Dependence on height for chronological age or bone age and the mean relative standard deviation were lowest in the PBI for both genders pooled. The differences in height dependence were statistically significant and are shown to be clinically relevant. Reference data for PBI are presented.

CONCLUSION

PBI may be a better indicator than BMD for bone health in children; however, verification in a clinical group is needed.

Comparison between amputation-induced demineralization and age-related bone loss using digital X-ray radiogrammetry

Digital X-ray radiogrammetry (DXR) is a computer-assisted automatic osteodensitometric tool. This study was performed to compare DXR measurements between bone changes following amputation trauma and age-related bone loss. Thirty-five men, who had undergone finger amputations, received a baseline examination and 2--3 serial measurements. As a second group, 215 males older than 70yr were enrolled. All patients obtained standardized hand radiographs. The following DXR parameters evaluating metacarpals were considered: cortical bone mineral density (DXR-BMD), cortical thickness (DXR-CT), metacarpal index (DXR-MCI), outer bone diameter (width; DXR-W), and inner medullary diameter (DXR-MD). In the amputation group, the DXR parameters showed an accentuated initial decrease between first and second measurements (DRX-BMD--12.7%, DXR-CT--14.2%, DXR-W--8.6%, DXR-MCI--6.1%; p<0.001) followed by a less pronounced reduction between second and third radiographs (DRX-BMD--0.5%, DXR-CT--1.5%, DXR-W--0.1%, DXR-MCI--1.3%). DXR-MD revealed a reduction of--3.6% (p<0.05) between first and second estimates and a non-significant increase (+1.1%) between second and third measurements. When compared with the second and third estimates in the amputation group, men older than 70yr presented lower DXR-BMD, DXR-CT, and DXR-MCI values (p<0.001), but larger metacarpal outer and inner bone diameters (DXR-W and DXR-MD; p<0.001). DXR-MD of the elderly men group was also more extended when compared with the baseline measurements of the amputation cohort (p<0.001). The early accentuated cortical bone loss and particularly the pronounced decrease of the outer bone width seem to be characteristic for amputation-induced osteoporosis, suggesting that this might be a distinct secondary osteoporosis entity. When compared with amputation-associated osteoporosis, where the bone loss occurs to a higher extent in the outer bone diameter than in the medullary cavity, the age-related bone changes lead more to an increase of the medullary diameter than of the outer bone width.