Secular trends in skeletal maturity in South Africa: 1962-2001

Body composition trajectories during childhood predict skeletal maturation at puberty: A longitudinal study

Nutritional status significantly impacts linear bone growth. We aimed to determine the relationship between the trajectories of four body composition indicators and pubertal advanced bone age. Trajectories of body mass index z-score (BMI z-score), visceral fat area z-score (VFA z-score), fat mass index z-score (FMI z-score), and fat-free mass index z-score (FFMI z-score) were identified based on three body composition measurements conducted from October 2018 to April 2023 within a pediatric cohort (the PROC study). We assessed pubertal bone age using the Tanner-Whitehouse 3-Chinese Radius-Ulna-Short (TW3-C RUS) method among 1402 primary school children. Children with a trajectory of higher BMI z-score, VFA z-score, FMI z-score, and FFMI z-score since childhood were more likely to have advanced bone age. The risk of advanced bone age was higher in children who were consistently in the high VFA z-score group (odds ratio [OR] = 6.73) or consistently in the high BMI z-score group (OR = 5.57), as compared to those in the low VFA z-score and low BMI z-score groups. Regular monitoring and maintenance of normal VFA during childhood may reduce the risk of advanced bone age at puberty. Furthermore, BMI monitoring is optional, especially in cases where specialized body composition equipment is not available.

Secular trends in physical growth, biological maturation, and intelligence in children and adolescents born between 1978 and 1993

Introduction

Human physical growth, biological maturation, and intelligence have been documented as increasing for over 100 years. Comparing the timing of secular trends in these characteristics could provide insight into what underlies them. However, they have not been examined in parallel in the same cohort during different developmental phases. Thus, the aim of this study was to examine secular trends in body height, weight, and head circumference, biological maturation, and intelligence by assessing these traits concurrently at four points during development: the ages of 4, 9, 14, and 18 years.

Methods

Data derived from growth measures, bone age as an indicator of biological maturation, and full-scale intelligence tests were drawn from 236 participants of the Zurich Longitudinal Studies born between 1978 and 1993. In addition, birth weight was analyzed as an indicator of prenatal conditions.

Results

Secular trends for height and weight at 4 years were positive (0.35 SD increase per decade for height and an insignificant 0.27 SD increase per decade for weight) and remained similar at 9 and 14 years (height: 0.46 SD and 0.38 SD increase per decade; weight: 0.51 SD and 0.51 SD increase per decade, respectively) as well as for weight at age 18 years (0.36 SD increase per decade). In contrast, the secular trend in height was no longer evident at age 18 years (0.09 SD increase per decade). Secular trends for biological maturation at 14 years were similar to those of height and weight (0.54 SD increase per decade). At 18 years, the trend was non-significant (0.38 SD increase per decade). For intelligence, a positive secular trend was found at 4 years (0.54 SD increase per decade). In contrast, negative secular trends were observed at 9 years (0.54 SD decrease per decade) and 14 years (0.60 SD decrease per decade). No secular trend was observed at any of the four ages for head circumference (0.01, 0.24, 0.17, and - 0.04 SD increase per decade, respectively) and birth weight (0.01 SD decrease per decade).

Discussion

The different patterns of changes in physical growth, biological maturation, and intelligence between 1978 and 1993 indicate that distinct mechanisms underlie these secular trends.

Pattern of linear growth and progression of bone maturation for girls with early-onset puberty: A mixed longitudinal study

Background and objective

With a worldwide trend to earlier age of onset of puberty, the prevalence of early-onset puberty (EP) among girls has increased. The impact of EP on the pattern of linear growth and bone maturation is unclear. Accordingly, the objective of our study was to describe this pattern for girls with EP in Shenzhen, China.

Methods

A total of 498 untreated girls diagnosed with EP at Shenzhen Children's Hospital, China, between January 2016 and December 2021. A total of 1,307 anthropometric measurements and 1,307 left-hand radiographs were available for analysis. Artificial intelligence (AI) was used to determine bone age (BA). Participants were classified into groups according to chronological age (CA) and BA. The pattern of linear growth (height) and progression of bone maturation was described between groups using the Lambda-Mu-Sigma (LMS) method. Published height-for-CA and height-for-BA norm references for a healthy Chinese population were used for age-appropriate comparisons.

Results

The mean CA of appearance of first pubertal signs (breast buds) was 8.1 ± 0.5 years. Compared to norm-referenced data, girls with EP were significantly taller at a CA of 7-10 years. This was followed by a slowing in linear growth after a CA of 10 years, with 71 girls with EP having already achieved their target adult height. From 7 to 10 years of BA, the linear growth was slower in the EP group compared to norm-reference values. This was followed by a period of catch-up growth at 11.2 years of BA, with growth curves approaching norm-referenced values. The BA progressed rapidly from 7 to 8 years of age in about half of the girls with EP (median ΔBA/ΔCA >1.9), slowing, thereafter, until the period of catch-up growth at 11.2 years of BA.

Conclusions

BA provides a more reliable reference than CA to assess growth parameters among girls with EP. Our limited data set does indicate that EP does not negatively impact final adult height. Therefore, the growth curves from our study are relevant, providing a reference for pediatricians in this clinical population and, thus, preventing over-treatment for EP.

Association between phthalate exposure and accelerated bone maturation in Chinese girls with early puberty onset: a propensity score-matched case-control analysis

Estrogen can promote the acceleration of bone maturation and phthalate esters (PAEs) have estrogen-mimicking effects. We investigated whether PAEs are associated with the acceleration of bone age (BA) in girls with early onset of puberty (EOP). This case–control study enrolled 254 girls with EOP from the Endocrinology Department at Shenzhen Children’s Hospital between December 2018 and August 2019. Ultra-performance liquid chromatography and tandem mass spectrometry were used to analyze the 10 metabolites of PAEs (mPAEs) in urine samples. BA was measured using an artificial intelligence system. BA exceeding the chronological age (CA) by > 2 years (BA-CA ≥ 2 years) was referred to as significant BA advancement. Participants were divided into groups A (BA-CA ≥ 2 years; case group) and B (BA-CA < 2 years; control group). Propensity score matching (PSM) was performed for both groups in a 1:2 ratio with a caliper of 0.25. To identify potential dose–response relationships between PAEs exposure and BA advancement, we grouped the participants after PSM according to the tertiles of the mPAE concentrations. After PSM, 31 and 62 girls in groups A and B were selected. The concentration of Mono-ethyl phthalate (MEP) in group A was significantly higher than in group B (11.83 μg/g vs. 7.11 μg/g, P < 0.05); there was no significant difference in the levels of other mPAEs between the groups. The degree of BA advancement and proportion of significantly advanced BA in the lowest, middle, and highest tertiles of the MEP sequentially increased, as well as in the lowest, middle, and highest tertiles of Mono-(2-ethyl-5-carboxypentyl) phthalate; however, these were only statistically different between the highest and lowest MEP tertiles (both P < 0.05). For the remaining mPAEs, differences in the degree of BA advancement among the lowest, middle, and highest tertiles, as well as differences in the proportion of significantly advanced BA among the lowest, middle, and highest tertiles, were not significant (all P > 0.05). Our findings suggested that MEP was positively associated with BA advancement in girls with EOP. Exposure to PAEs may promote accelerated bone maturation.

The skeletal maturity of Australian children aged 10-13 years in 2016

Skeletal maturity can be used as a biological indicator of the tempo of growth in children and adolescents. We present a description of skeletal maturity from a cohort of white Australian children and describe variation in skeletal maturity based on child age. Participants (n = 71; age 10.5-13.9 years) were recruited from the 'Healthy, Active Preschool & Primary Years (HAPPY)' study. Left hand-wrist radiographs were used to determine skeletal maturity using the Tanner-Whitehouse III (TW3) RUS technique. In boys, the mean skeletal maturity offset (bone age - chronological age) was -0.12 ± 0.19 years and 57.9% had delayed skeletal maturity compared to chronological age. Among those with delayed skeletal maturity, the average delay was 0.99 years (range 0.02-2.54 years). In girls, skeletal age was advanced, on average, compared to chronological age by 0.32 ± 0.20 years. Among the 39.4% of girls with delayed skeletal maturity, the average delay was 0.48 years (range: 0.01-2.28). Four children in the sample exhibited a delay in skeletal maturity greater than 2 years. In the context of secular trends towards advanced skeletal maturity observed globally, delayed skeletal maturation in this white, economically privileged cohort are surprising and warrant further exploration.

Age estimation in the living: A scoping review of population data for skeletal and dental methods

Age estimation of living individuals has become a crucial part of the forensic practice, especially due to the global increase in cross-border migration. The low rate of birth registration in many countries, hence of identification documents of migrants, especially in Africa and Asia, highlights the importance of reliable methods for age estimation of living individuals. Despite the fact that a number of skeletal and dental methods for age estimation have been developed, their main limitation is that they are based on specific reference samples and there is still no consensus among researchers on whether these methods can be applied to all populations. Though this issue remains still unsolved, population information at a glance could be useful for forensic practitioners dealing with such issues. This study aims at presenting a scoping review and mapping of the current situation concerning population data for skeletal (hand-wrist and clavicle) and dental methods (teeth eruption and third molar formation) for age estimation in the living. Two hundred studies on the rate of skeletal maturation and four hundred thirty-nine on the rate of dental maturation were found, covering the period from 1952 and 2020 for a total of ninety-eight countries. For most of the western and central African countries there are currently no data on the rate of skeletal and dental maturation. The same applies to the countries of the Middle East, as well as the eastern European countries, especially as regard the skeletal development.

Secular trend of the skeletal maturation in relation to peak height velocity-a comparison between two groups of children born 1969-1973 and 1996-2000

BACKGROUND/OBJECTIVES

The aims were to study the presence of a secular trend in (a) age at peak height velocity (PHV), (b) velocity at PHV, and (c) duration of skeletal maturation in relation to PHV.

MATERIAL/METHOD

Two groups of children: 100 children (63 boys, 37 girls) born between 1969-1973 and 71 children (49 boys, 22 girls) born between 1996 and 2000, were compared. Age and velocity at PHV were measured on individual growth velocity curves. Skeletal maturation stages were assessed on hand-wrist radiographs, and duration from the skeletal maturation stages to PHV was determined.

RESULTS

Age at PHV occurred significantly earlier (0.47 years, CI 95% 0.19-0.76, P < 0.001), and velocity at PHV was significantly higher (0.68 cm/year, CI 95% 1.47-2.06, P < 0.003) in children born 1996-2000 compared to 1969-1973. No significant difference in duration of skeletal maturation was seen between the groups. Skeletal maturation stages occurred significantly in the following order before PHV for both genders: PP2= 2.18 years (P = 0.002), MP3= 1.60 year (P = 0.008), S 1.07 year (P = 0.003), and MP3cap 0.38 year (P = 0.037).

LIMITATIONS

Most radiographs were taken before PHV, the duration thus mainly reflects the early event of pubertal growth spurt.

CONCLUSION

A secular trend was evident: significantly decreased age at PHV and significantly increased velocity at PHV. No evidence of a secular trend regarding duration of the skeletal maturation in relation to PHV was found. Due to the declining age at PHV, the skeletal maturation stages occurred earlier in relation to chronological age.

Accelerated skeletal maturation is associated with overweight and obesity as early as preschool age: a cross-sectional study

Background

Body mass index (BMI) and skeletal age (SA) are important indicators of individual growth and maturation. Although the results have not been unified, most studies indicated that accelerated skeletal maturation is associated with overweight/obesity. However, there have so far been insufficient studies about the association between accelerated skeletal maturation and overweight/obesity in preschoolers, particularly Asian children. A cross-sectional study was conducted on Chinese children to verify the association between accelerated skeletal maturation and overweight/obesity at preschool age.

Methods

The study involved 1330 participants aged 3.1–6.6 years old (730 males and 600 females) in Shanghai, China. The skeletal age was determined according to the method of TW3-C RUS. Accelerated skeletal maturation was defined as relative SA (SA minus chronological age [CA]) ≥1.0 years. BMI was classified as thinness, normal weight, overweight, and obesity according to the International Obesity Task Force (IOTF) BMI cut-offs. The Chi-square was performed to determine the statistically significant difference in the frequency of accelerated skeletal maturation in BMI and age categories. The logistic regression model analyzed the association between accelerated skeletal maturation and overweight/obesity.

Results

The percentage of accelerated skeletal maturation increased with BMI (7.8% of children in thinness group had accelerated skeletal maturation; the percentage increased to 30.8% in obese group. x² = 89.442, df = 3, P < 0.01) and age group (at age 3.5, 3.5% of participants had accelerated skeletal maturation; at age 6.0 years, this increased to 27.8%. x² = 43.417, df = 5, P < 0.01). Logistic regression analysis showed that children with overweight and obesity are more likely to have accelerated skeletal maturation than children with normal weight after adjusting for gender and age (Overweight, odds ratio [OR] = 3.27, 95% confidence interval [CI]: 2.20–4.87; Obese, OR = 4.73, 95% CI: 2.99–7.48).

Conclusions

There is an association between accelerated skeletal maturation and overweight/obesity among preschool children. This study suggests that accelerated skeletal maturation might coexist with overweight/obesity in preschool children, and interventions, such as dietary modifications and increasing levels of physical activity, should be employed to prevent both accelerated skeletal maturation and overweight/obesity as early as preschool age.

Adolescent growth and BMI and their associations with early childhood growth in an urban South African cohort

OBJECTIVES

The timing and magnitude of adolescent growth may be influenced by ethnicity and early life factors. We aimed to (a) characterize ethnic differences in the magnitude, timing, and intensity of adolescent growth in height, weight, and BMI; (b) assess the effect of early childhood growth on adolescent growth in black children.

METHODS

Data were from the Birth to Twenty Plus cohort (Bt20+) in Johannesburg, South Africa (n = 3273). Height, weight, and BMI were modeled with ethnic comparisons using the SuperImposition by Translation and Rotation for 2089 participants who had data from 7 to 23 years. Relative weight gain and relative linear growth between 0 and 24 months and 24 and 60 months were generated. Multiple regression analyses were used to assess associations between childhood and adolescent growth.

RESULTS

White children were 5 cm (SE: 0.7) taller than black children through adolescence. Black boys had a later timing of adolescent height (0.65 years ±0.12) than white boys, which in black girls was 0.24 years (0.11) earlier than in white girls. Black girls had faster BMI velocity than white girls. Among black children, birth weight and both relative weight gain 0 to 24 and relative linear growth between 3 and 24 months and 24 and 60 months were positively associated with the magnitude of adolescent growth and negatively associated with timing.

CONCLUSION

Sex dimorphism in ethnic differences in timing of adolescent height growth may reflect some yet unexplained drivers for rapid weight gain and obesity in black females but not black males. Rapid weight gain in early life may contribute to faster adiposity accrual in adolescence.

Secular trends in cranial size and shape among black South Africans over the late 19th and 20th centuries

BACKGROUND

Previous studies of secular change in cranial size among black South Africans have produced conflicting results.

AIM

We re-examined cranial size change in this population during the 19th and 20th century by evaluating its relationship with individual year-of-birth, and the significance of trends among eight decennial cohorts.

SUBJECTS AND METHODS

This study is based on 102 male and 89 female adults born between 1865 and 1959. Linear regressions were employed to evaluate possible relationships between year-of-birth and cranial dimensions; ANOVAs were used to evaluate the significance of long-term trends among decennial cohorts.

RESULTS

No analysis revealed a secular change in cranial length in either sex; however, the ANOVA for cranial length in the combined sex sample was significant. There is no secular trend in female cranial breadth, but males display a negative trend in this dimension. This results in a secular trend for increased male dolichocephaly.

CONCLUSIONS

The factors that underlie the negative secular trend in male cranial breadth and the absence of a secular trend in overall cranial size in this population are unclear. Nevertheless, these observations accord with findings related to stature and long bone strength in this population and are consistent with observations for other sub-Saharan African populations.

Secular decline in limb bone strength among South African Africans during the 19th and 20th centuries

OBJECTIVES

South African Africans have been reported to have experienced negative or null secular trends in stature and other measures of skeletal structure across the 19th and 20th centuries, presumably due to poor living conditions during a time of intensifying racial discrimination. Here, we investigate whether any secular trend is apparent in limb bone strength during the same period.

MATERIALS AND METHODS

Cadaver-derived skeletons (n = 221) were analyzed from female and male South African Africans who were born between 1839 and 1970, lived in and around Johannesburg, and died between 1925 and 1991 when they were 17-90 years of age. For each skeleton, a humerus and femur were scanned using computed tomography, and mid-diaphyseal cross-sectional geometric properties were calculated and scaled according to body size.

RESULTS

In general linear mixed models accounting for sex, age at death, and skeletal element, year of birth was a significant (p < .05) negative predictor of size-standardized mid-diaphyseal cortical area (a proxy for resistance to axial loading) and polar moment of area (a proxy for resistance to bending and torsion), indicating a temporal trend toward diminishing limb bone strength. No significant interactions were detected between year of birth and age at death, suggesting that the decline in limb bone strength was mainly due to changes in skeletal maturation rather than severity of age-related bone loss.

DISCUSSION

Limb bone strength is thus potentially another feature of the skeletal biology of South African Africans that was compromised by poor living conditions during the 19th and 20th centuries.

Craniofacial growth spurt in Class I subjects

INTRODUCTION

The objective was to study the growth spurt of Class I subjects, focusing on the ability to predict the peak of the growth spurt of the maxillary (Co-A) and mandibular (Co-Pog) lengths from the maturational changes of the cervical vertebrae.

METHODS

The longitudinal lateral cephalographs of 14 males (ages, 10-15 years) and 12 females (ages, 9-14 years) were selected from the Craniofacial Growth Studies Legacy Collection of the American Association of Orthodontists Foundation. The cephalographs were taken at regular 1-year intervals. A cervical vertebral maturation (CVM) method that divided skeletal maturation into 6 stages was used for growth prediction. Growth increments calculated for the annual age intervals were used to examine the diagnostic performance of the CVM method.

RESULTS

In males, the most peaks for Co-Pog were detected in the CVM3-CVM4 interval in 7 males (50%); for Co-A, the most peaks were found in the CVM2-CVM3 interval in 7 males (50%). In females, the most peaks for both Co-Pog and Co-A were seen in the CVM2-CVM3 interval in 7 females (58%) and in 6 females (50%), respectively. The fewest peaks were detected in CVM4-CVM5 for both males and females.

CONCLUSIONS

In Class I subjects with balanced anteroposterior jaw relationships, presence of CVM3 would indicate the peak of the growth spurt, and CVM2 would mean that the peak has not yet arrived. During CVM2, the shapes of cervical vertebrae 3 and 4, whether trapezoid or horizontal rectangular, would indicate whether the subject is in the early CVM2 or is about to be in CVM3.

Evidence of secular trend in mandibular pubertal growth

Background

During puberty, mandibular growth follows a growth curve comparable to somatic growth. This study aimed to review the relationship between mandibular pubertal peak height velocity (PHV) and skeletal age, and to investigate the possibility of a secular trend.

Methods

Retrospective analysis was performed of two historical craniofacial growth studies (Denver Growth Study; observational time: 1943-1965, and Zurich Growth Study; observational time: 1982-1984) of healthy untreated subjects. Two mandibular growth measures (Articulare-Pogonion [Ar-Pg], Condylion-Pogonion [Co-Pg]) were retrieved from cephalograms (n: 990) and corresponding skeletal age based on hand-wrist radiographs. Mandibular growth velocity was related to skeletal age, PHV was established by use of cubic smoothing splines and variability was calculated by bootstrap resampling for every growth study and gender separately.

Results

Sexual dimorphism in mandibular growth was apparent in both cohorts. In subjects of the Denver Growth Study, mandibular PHV occurred at a more advanced skeletal age than in subjects of the Zurich Growth Study. This trend was more pronounced in males, for whom PHV of Co-Pg shifted from 14.4 to 13.8 years and of Ar-Pg from 14.6 to 13.7 years. This tendency was more subtle in females: PHV of Co-Pg shifted from 12.7 to 12.4 years and of Ar-Pg from 12.6 to 11.8 years.

Conclusions

Mandibular growth appears to be subject to a secular trend. When related to skeletal age, this secular trend seems to be more accentuated than the established secular trend for somatic pubertal growth.

Early Maturity as the New Normal: A Century-long Study of Bone Age

BACKGROUND

Epiphyseal fusion (EF) marks the completion of longitudinal bone growth, a critical milestone monitored during treatment of skeletal growth and/or developmental disorders. Recently, a trend toward accelerated skeletal maturation in children has been documented. Because current methods for assessing skeletal maturation include children in their reference populations born as early as the 1930s, the timing of EF events in contemporary patients may differ substantially from those standards.

QUESTIONS/PURPOSES

(1) Do children today initiate the process of EF in the hand and wrist earlier than past generations on which maturity standards are based? (2) Do children today complete EF in the hand and wrist earlier than past generations on which maturity standards are based?

METHODS

A total of 1292 children (665 males, 627 females) participating in the Fels Longitudinal Study, born between 1915 and 2006, were included in this retrospective, observational study. Each participant had between one and 39 serial left hand-wrist radiographs during childhood obtained specifically for research purposes. Main outcomes were the chronological age at the first sign of EF initiation (EF-I) and the first chronological age when EF was complete (EF-C) in the radius and ulna, and metacarpals and phalanges of the first, third, and fifth rays according to criteria of the Fels method. EF is a reliable metric with an average κ agreement statistic of 0.91. Penalized B-splines were used to model the changes in EF-I and EF-C ages and to identify changes across continuous birth years with major comparisons between children born in 1935 and 1995.

RESULTS

Approximately half of the epiphyses of the hand and wrist examined exhibited earlier EF-I and/or earlier EF-C in children born in 1995 compared with those born in 1935. The age at each milestone (EF-I and EF-C) decreased by as much as 6.7 and 6.8 months in males and 9.8 and 9.7 months in females, respectively. This change occurred gradually over the past century. The more proximal traits (EF of the distal radius, distal ulna, and metacarpals) were more likely to experience a shift in timing, whereas timing of EF in the phalanges remained relatively stable across birth years.

CONCLUSIONS

A trend has occurred over the past century in the timing of EF, in both initiation and completion of the process, for many of the bones of the hand and wrist. Earlier EF reflects modern population advances in both skeletal and sexual maturation. Shifts in the timing of EF have the potential to influence treatment strategies for skeletal growth and/or developmental disorders such as scoliosis or leg length inequality, moving treatment windows to earlier ages. Earlier EF-I and EF-C identified in this study signals a need to reevaluate the timing of maturational milestones and current standards for skeletal assessment.

LEVEL OF EVIDENCE

Level II, prognostic study.

Morphometric analysis of the humerus in an adult South African cadaveric sample

Recent studies using geometric morphometrics have shown that estimations of demographic parameters can be made using skeletal elements previously not thought useful for such purposes. This study used geometric morphometrics to assess humeral morphological variation in an adult South African sample, and evaluated the accuracy of sex and ancestry estimations based on this variation. Humeri of 1046 adult South African individuals (464 females, 582 males) were digitized. Data sets were rotated and scaled to a common centroid using Generalized Procrustes Analysis. Mean centroid sizes between groups were compared using parametric tests, while morphological variation was evaluated using multivariate analyses. Discriminant Function Analysis coupled with leave-one-out cross-validation tests were used to assess the reliability of sex and ancestry classifications based on this variation. Male humeri were relatively larger and presented with morphological features indicative of larger muscle mass and smaller carrying angles than females. White individuals had relatively larger but morphologically less robust humeri than Black or Coloured individuals, likely a reflection of both genetic and socio-economic differences between the groups as enforced under Apartheid law. When sex and ancestry were assessed together, similar variations were detected than when either parameter was individually assessed. Classification accuracy was relatively low when sex was independently assessed (73.3%), but increased when considered in conjunction with ancestry, indicating greater variation between-groups (ancestry) than within-groups. Ancestry estimation accuracies exceeded 80%, even for the highly diverse Coloured group. Classification accuracies of sex-ancestry groups all exceeded 76%. These results show that humerus morphological variation is present and may be used to estimate parameters, such as sex and ancestry, even in complex groups such as the Coloured sample of this study.

The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain)

Ontogenetic studies help us understand the processes of evolutionary change. Previous studies on Neandertals have focused mainly on dental development and inferred an accelerated pace of general growth. We report on a juvenile partial skeleton (El Sidrón J1) preserving cranio-dental and postcranial remains. We used dental histology to estimate the age at death to be 7.7 years. Maturation of most elements fell within the expected range of modern humans at this age. The exceptions were the atlas and mid-thoracic vertebrae, which remained at the 5- to 6-year stage of development. Furthermore, endocranial features suggest that brain growth was not yet completed. The vertebral maturation pattern and extended brain growth most likely reflect Neandertal physiology and ontogenetic energy constraints rather than any fundamental difference in the overall pace of growth in this extinct human.

Assessing the use of the anatomical method for the estimation of sub-adult stature in Black South Africans

Stature estimation is rarely attempted in sub-adults due to the general lack of available standards as a result of the dearth of sufficiently large sub-adult skeletal collections with known demographic information. To overcome this problem sub-adult research mainly relies on modern imaging modalities. In the current study Magnetic Resonance Imaging (MRI) scans were used to assess the use of the anatomical method for stature estimation in sub-adults. A total of 53 Black South African sub-adult males (n=24) and females (n=29) aged between 10 and 17 years participated in the study by voluntarily completing a full-body MRI scan. A stadiometer was used to measure living stature prior to all MRI scans. Skeletal elements that contribute directly to stature were measured from the MRI scans using OsiriX and summed to compute the total skeletal height. Total skeletal height was calculated using the diaphyseal, maximum and physiological long bone lengths and correlated to living stature using Pearson's correlations. Subsequently least squares regression equations were generated for the estimation of sub-adult stature. Results indicated strong, statistically significant positive correlations between living stature and total skeletal heights in sub-adult males, females and a combined sex sample. The regression equations were characterized by small standard error of estimates which are comparable to that reported for Black South African adults. Based on these results the anatomical method can be used to accurately describe living stature in Black South African sub-adults. This method is therefore encouraged as it will add valuable information when dealing with unknown sub-adult skeletal remains.

Ethnic Differences in Peripheral Skeletal Development Among Urban South African Adolescents: A Ten-Year Longitudinal pQCT Study

There are no longitudinal pQCT data of bone growth and development from sub-Saharan Africa, where rapid environmental, societal, and economic transitions are occurring, and where fracture rates are predicted to rise. The aim of this study was to compare skeletal development in black and white South African adolescents using longitudinal data from the Birth to Twenty study. The Birth to Twenty Bone Health subcohort consisted of 543 adolescents (261 [178 black] girls, 282 [201 black] boys). Annual pQCT measurements of the radial and tibial metaphysis and diaphysis were obtained between ages 12 and 22 years (distal metaphysis: cross-sectional area [CSA] and trabecular bone mineral density [BMD]; diaphysis: total and cortical CSA, cortical BMD, and polar stress-strain index [SSIp]). Age at peak height velocity (APHV) was calculated to account for differences in maturational timing between ethnic groups and sexes. Mixed-effects models were used to describe trajectories for each pQCT outcome. Likelihood-ratio tests were used to summarize the overall difference in trajectories between black and white participants within each sex. APHV (mean ± SD years) was similar in black (11.8 ± 0.8) and white (12.2 ± 1.0) girls, but delayed in black (14.2 ± 1.0) relative to white boys (13.3 ± 0.8). By 4 years post-APHV, white adolescents had significantly greater cortical CSA and SSIp than black adolescents at the radius. There were no significant differences at the radial metaphysis but there was some divergence, such that black adolescents had greater radial trabecular BMD by the end of follow-up. At the tibia, white adolescents had lower diaphyseal CSA and SSIp, and greater metaphyseal CSA. There was no ethnic difference in tibial trabecular BMD. There are ethnic differences in bone growth and development, independent of maturation, in South African adolescents. This work gives new insights into the possible etiology of childhood fractures, which occur most commonly as peripheral sites. © 2017 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Secular trends in the timing of skeletal maturation as assessed by the cervical vertebrae maturation method

Objective

To investigate the presence of secular trends in skeletal maturation of girls and boys as assessed by the use of cervical vertebrae bones.

Materials and methods

The study compared two main groups: the first included data collected from the Denver growth study (1930s to 1960s) and the second included data collected from recent pretreatment records (1980s to 2010s) of patients from the orthodontic clinic of a North American University. The records from the two groups were all for Caucasian subjects. The sample for each group included 78 lateral cephalographs for girls and the same number for boys. The age of the subjects ranged from 7 to 18 years. Cervical vertebrae maturation (CVM) stages were directly assessed from the radiographs according to the method described by Hassel and Farman in which six CVM stages were designated from cervical vertebrae 2, 3, and 4.

Results

The mean age of girls from the Denver growth study and girls from the university clinic in each of the six CVM stages was not different at P ≤0.05. However, the mean age of boys from the two groups was not different only in stage 3 (P = 0.139) and stage 4 (P = 0.211).

Conclusions

The results showed no evidence to indicate a tendency for earlier skeletal maturation of girls or boys. Boys in the university group started their skeletal maturation later than boys in the Denver group and completed their maturation earlier. Gender was a significant factor affecting skeletal maturation stages in both Denver and university groups.

Changes in body mass, stature and BMI in South African elite U18 Rugby players from different racial groups from 2002-2012

The purpose of this study was to determine whether there are differences between racial groups for body mass, stature and body mass index (BMI) in South African elite U18 rugby players and whether there were significant changes in these measurements between 2002 and 2012. Self-reported body mass and stature were obtained from U18 players (n = 4007) who attended the national tournament during this period. BMI was calculated for each player.White players were 9.8 kg heavier than black players, who were 2.3 kg heavier than coloured players (P < 0.0001). The body mass of all groups increased from 2002 to 2012 (P < 0.0001). White players were 7.0 cm taller than black players who were 0.5 cm taller than coloured players (P < 0.0001). Players' stature measurements did not change significantly during the study period. The average BMI of white players was 0.9 kg·m^-2 greater than black players who were on average 0.7 kg·m^-2 greater than coloured players (P < 0.0001). The BMI of all groups changed similarly over the study period. The body mass, stature and BMI of elite under-18 rugby players in South Africa were significantly different between racial groups. This has implications for transforming the game to make it representative of the South African population.

Stature estimation from the femur and tibia in Black South African sub-adults

Stature estimation can play a role in the positive identification of unknown individuals and as such it is routinely assessed during the examination of adult remains. Unfortunately, this is not a standard procedure when dealing with sub-adult remains due to the general lack of standard procedures for the estimation of sub-adult stature. The aim of this study was therefore to derive regression equations for the estimation of stature in black South African sub-adults. Fifty nine black South African sub-adult males and females, aged 10-17 years, voluntarily participated in the study by undergoing a full body Magnetic Resonance Imaging (MRI) scan. Living stature was measured with a stadiometer and the maximum and diaphyseal lengths of the femur and tibia were measured from the MRI scans using the image processing software OsiriX. Pearson's correlation coefficients and linear least square regression analyses were used to assess the correlations between living stature and the measurements and to generate sub-adult stature estimation equations for males, females and a combined sex sample. Measurements of the femur, tibia and the combined measures thereof showed strong statistically significant positive correlations with living stature, while the obtained regression equations were characterized by low standard error of estimates. The strong correlations and low standard error of estimates are comparable to stature estimation models reported for Black South African adults and therefore these variables can be considered good estimators of sub-adult stature which will contribute valuable information to the biological profile of unidentified sub-adult skeletal remains.

Do Secular Trends in Skeletal Maturity Occur Equally in Both Sexes?

BACKGROUND

Skeletal maturity assessment provides information on a child's physical development and expectations based on chronological age. Given recently recognized trends for earlier maturity in a variety of systems, most notably puberty, examination of sex-specific secular trends in skeletal maturation is important. For the orthopaedist, recent trends and changes in developmental timing can affect clinical management (eg, treatment timing) if they are currently based on outdated sources.

QUESTIONS/PURPOSES

(1) Has the male or female pediatric skeleton experienced a secular trend for earlier maturation over the past 80 years? (2) Do all indicators of maturity trend in the same direction (earlier versus later)?

METHODS

In this retrospective study, a total of 1240 children were examined longitudinally through hand-wrist radiographs for skeletal maturity based on the Fels method. All subjects participate in the Fels Longitudinal Study based in Ohio and were born between 1930 and 1964 for the "early" cohort and between 1965 and 2001 for the "recent" cohort. Sex-specific secular trends were estimated for (1) mean relative skeletal maturity through linear mixed models; and (2) median age of maturation for individual maturity indicators through logistic regression and generalized estimating equations.

RESULTS

Overall relative skeletal maturity was significantly advanced in the recent cohort (maximum difference of 5 months at age 13 years for girls, 4 months at age 15 years for boys). For individual maturity indicators, the direction and magnitude of secular trends varied by indicator type and sex. The following statistically significant secular trends were found: (1) earlier maturation of indicators of fusion in both sexes (4 months for girls, 3 months for boys); (2) later maturation of indicators of projection in long bones in both sexes (3 months for girls, 2 months for boys); (3) earlier maturation of indicators of density (4 months) and projection (3 months) in carpals and density in long bones (6 months), for girls only; and (4) later maturation of indicators of long bone shape (3 months) for boys only.

CONCLUSIONS

A secular trend has occurred in the tempo of maturation of individual components of the pediatric skeleton, and it has occurred in a sex-specific manner. The mosaic nature of this trend, with both earlier and later maturation of individual components of the skeletal age phenotype, calls for greater attention to specific aspects of maturation in addition to the overall skeletal age estimate. The Fels method is currently the most robust method for capturing these components, and future work by our group will deliver an updated, user-friendly version of the Fels assessment tool.

CLINICAL RELEVANCE

Appreciation of sex-specific secular changes in maturation is important for clinical management, including treatment timing, of orthopaedic patients, because children today exhibit a different pattern of maturation than children on whom original maturity assessments were based (including Fels and Greulich-Pyle).

Ethnic and sex differences in skeletal maturation among the Birth to Twenty cohort in South Africa

AIM

To examine ethnic and sex differences in the pattern of skeletal maturity from adolescence to adulthood using a novel longitudinal analysis technique (SuperImposition by Translation And Rotation (SITAR)).

SETTING

Johannesburg, South Africa.

PARTICIPANTS

607 boys and girls of black as well as white ethnicity from the Birth to Twenty bone health study, assessed annually from 9 to 20 years of age.

OUTCOME MEASURE

Bone maturity scores (Tanner-Whitehouse III radius, ulna, and short bones (TW3 RUS)) assessed longitudinally from hand-wrist radiographs were used to produce individual and mean growth curves of bone maturity and analysed by the SITAR method.

RESULTS

The longitudinal analysis showed that black boys matured later by 7.0 SE 1.6 months (p<0.0001) but at the same rate as white boys, whereas black girls matured at the same age but at a faster rate than white girls (by 8.7% SE 2.6%, p=0.0007). The mean curves for bone maturity score consistently showed a midpubertal double kink, contrasting with the quadratic shape of the commonly used reference centile curves for bone maturity (TW3).

CONCLUSIONS

Skeletal maturity was reached 1.9 years earlier in girls than boys, and the pattern of maturation differed between the sexes. Within girls, there were no ethnic differences in the pattern or timing of skeletal maturity. Within boys, however, skeletal maturity was delayed by 7 months in black compared with white ethnicity. Skeletal maturation, therefore, varies differentially by sex and ethnicity. The delayed maturity of black boys, but not black girls, supports the hypothesis that boys have greater sensitivity to environmental constraints than girls.

Evidence of an overweight/obesity transition among school-aged children and youth in Sub-Saharan Africa: a systematic review

BACKGROUND

Prevalence of childhood overweight/obesity has increased considerably in recent years. The transition to higher rates of overweight/obesity has been well documented in high income countries; however, consistent or representative data from lower income countries is scarce. It is therefore pertinent to assess if rates of overweight/obesity are also increasing in lower income countries, to inform public health efforts.

OBJECTIVE

This systematic review aimed to investigate the evidence for an overweight/obesity transition occurring in school-aged children and youth in Sub Saharan Africa.

METHODS

Studies were identified by searching the MEDLINE, Embase, Africa Index Medicus, Global Health, Geobase, and EPPI-Centre electronic databases. Studies that used subjective or objective metrics to assess body composition in apparently healthy or population-based samples of children and youth aged 5 to 17 years were included.

RESULTS

A total of 283 articles met the inclusion criteria, and of these, 68 were used for quantitative synthesis. The four regions (West, Central, East, and South) of Sub Saharan Africa were well represented, though only 11 (3.9%) studies were nationally representative. Quantitative synthesis revealed a trend towards increasing proportions of overweight/obesity over time in school-aged children in this region, as well as a persistent problem of underweight. Weighted averages of overweight/obesity and obesity for the entire time period captured were 10.6% and 2.5% respectively. Body composition measures were found to be higher in girls than boys, and higher in urban living and higher socioeconomic status children compared to rural populations or those of lower socioeconomic status.

CONCLUSIONS

This review provides evidence for an overweight/obesity transition in school-aged children in Sub Saharan Africa. The findings of this review serve to describe the region with respect to the growing concern of childhood overweight/obesity, highlight research gaps, and inform interventions.

PROSPERO REGISTRATION NUMBER

CRD42013004399.

Predicting the timing of maturational spurts in skeletal age

Measures of maturity provide windows into the timing and tempo of childhood growth and maturation. Delayed maturation in a single child, or systemically in a population, can result from either genetic or environmental factors. In terms of the skeleton, delayed maturation may result in short stature or indicate another underlying issue. Thus, prediction of the timing of a maturational spurt is often desirable in order to determine the likelihood that a child will catch up to their chronological age peers. Serial data from the Fels Longitudinal Study were used to predict future skeletal age conditional on current skeletal age and to predict the timing of maturational spurts. For children who were delayed relative to their chronological age peers, the likelihood of catch-up maturation increased through the average age of onset of puberty and decreased prior to the average age of peak height velocity. For boys, the probability of an imminent maturational spurt was higher for those who were less mature. For girls aged 11 to 13 years, however, this probability was higher for those who were more mature, potentially indicating the presence of a skeletal maturation plateau between multiple spurts. The prediction model, available on the web, is most relevant to children of European ancestry living in the Midwestern US. Our model may also provide insight into the tempo of maturation for children in other populations, but must be applied with caution if those populations are known to have high burdens of environmental stressors not typical of the Midwestern US.

Bone age in the 21st century: is Greulich and Pyle's atlas accurate for Israeli children?

BACKGROUND

The applicability today of Greulich and Pyle's Radiographic Atlas of Skeletal Development of the Hand and Wrist (G&P) is uncertain.

OBJECTIVE

The purpose of this study was to determine whether G&P is accurate in Israeli children today.

MATERIALS AND METHODS

Left-hand radiographs of 679 children (375 boys) ranging in age from 1 day to 18 years old were obtained for trauma in the period 2001-2009 and were evaluated for bone age according to G&P. Individual bone age was plotted against calendar age and smoothed to obtain the association between calendar age and bone age. Any difference was assessed with Wilcoxon signed-rank test.

RESULTS

In girls, there was no significant difference between bone age and calendar age (P = 0.188). G&P underestimated bone age in boys <15 years old (median difference, 2.3 months; P < 0.0001) and overestimated bone age in boys ≥15 years old (median difference, 2.9 months; P = 0.0043). The largest median difference (5.4 months; P = 0.0003) was seen in boys 6-10 years old.

CONCLUSION

The differences between calendar age and bone age according to G&P were relatively small compared with normal variance and are unlikely to be of clinical importance.

Determinants of relative skeletal maturity in South African children

The variation of skeletal maturity about chronological age is a sensitive indicator of population health. Age appropriate or advanced skeletal maturity is a reflection of adequate environmental and social conditions, whereas delayed maturation suggests inadequate conditions for optimal development. There remains a paucity of data, however, to indicate which specific biological and environmental factors are associated with advancement or delay in skeletal maturity. The present study utilises longitudinal data from the South African Birth to Twenty (Bt20) study to indentify predictors of relative skeletal maturity (RSM) in early adolescence. A total of 244 black South African children (n=131 male) were included in this analysis. Skeletal maturity at age 9/10 years was assessed using the Tanner and Whitehouse III RUS technique. Longitudinal data on growth, socio-economic position and pubertal development were entered into sex-specific multivariable general linear regression models with relative skeletal maturity (skeletal age-chronological age) as the outcome. At 9/10 years of age males showed an average of 0.66 years delay in skeletal maturation relative to chronological age. Females showed an average of 1.00 year delay relative to chronological age. In males, being taller at 2 years (p<0.01) and heavier at 2 years (p<0.01) predicted less delay in RSM at age 9/10 years, independent of current size and body composition. In females, both height at 2 years and conditional weight at 2 years predicted less delay in RSM at 9/10 years (p<0.05) but this effect was mediated by current body composition. Having greater lean mass at 9/10 years was associated with less delayed RSM in females (p<0.01) as was pubertal status at the time of skeletal maturity assessment (p<0.01). This study identifies several predictors of skeletal maturation at 9/10 years, indicating a role for early life exposures in determining the rate of skeletal maturation during childhood independently of current stature.

SECULAR CHANGES IN HEIGHT, BODY WEIGHT, BODY MASS INDEX AND PUBERTAL DEVELOPMENT IN MALE CHILDREN AND ADOLESCENTS IN KRAKOW, POLAND

This study examined the secular changes in height, body weight, body mass index and pubertal development in male children and adolescents in Krakow (Poland) over the past 80 years, with an emphasis on the last decade (2000–2010). The survey of the population of Krakow is a continuation of observations conducted in that area for many years. The analysis aims to determine whether in the last decade Krakow still witnessed the secular trend, and what form the trend took. The body height and weight, and body mass index (BMI), of 1862 boys aged 3.5–18.5 years were analysed, against the background of a survey series from the years 1938 (N=1801), 1971 (N=2045), 1983 (N=3124) and 2000 (N=2328). The mean body height, in almost all age categories, was greater than in the past; however the final height over the last decade remained the same. The mean values of body weight and BMI increased, especially in the last decade. Also, an acceleration of puberty in boys was observed. The last 10 years saw an over 3-month decrease in the age of initial appearance of pubic hair in boys. In conclusion, the last decade saw cessation of the growing taller trend: maximum body height stabilized at approximately 179 cm, but weight and BMI increased. Also, a distinct acceleration of puberty was noticed. Lack of height increase, at the same time as weight gain and puberty acceleration, indicate a progressing developmental disharmony.

Trends in weights, heights, BMI and comparison of their differences in urban and rural areas for Iranian children and adolescents 2-18-year-old between 1990-1991 and 1999

BACKGROUND

Secular trends in height and weight are interesting because in middle- and low-income countries they are a marker for changes in population health. The present study aims to evaluate the secular trend in height and weight and body mass index (BMI) of Iranian children and adolescents aged 2-18 years old between 1990-1991 and 1999 and compare the magnitude of urban-rural differences during this period for the first time in an Asian country.

METHODS

Data from two national health surveys in 1990-1991 and 1999, of 22,349 and 25,196 weight and height measures of Iranian children and adolescents were used to study the trend and compare its difference in urban and rural children. Logarithmic transformation of weight, height and BMI was modelled as a polynomial in age for urban and rural boys and girls in each survey separately. The trend in urban and rural growth indexes (weight, height and BMI) and also the comparisons of urban-rural differences between two national surveys were tested in logarithmic scale using a weighted form of Z statistic for comparison of two means adjusted for age groups.

RESULTS

Urban and rural boys and girls became taller and heavier (P≤ 0.02) with no change of BMI (P > 0.05) during the period. There was not any significant difference between the magnitudes of urban-rural difference between two surveys (P≥ 0.61).

CONCLUSION

Although generally positive weight and height trend was observed among urban and rural residents, the magnitude of their differences was not changed.