Height and weight percentile curves of Beijing children and adolescents 0-18 years, 1995

Percent Final Height Is a Novel Method That Identifies Differences Between the Rate of Development in American Children of Different Races

INTRODUCTION

The Greulich & Pyle (G&P) Radiographic Atlas of Skeletal Development uses hand x-rays obtained between 1926 and 1942 on children of Caucasian ancestry. Our study uses modern Caucasian, Black, Hispanic, and Asian children to investigate patterns of development as a function of percent final height (PFH).

METHODS

A retrospective review, at a single institution, was conducted using children who received a hand x-ray, a height measurement taken within 60 days of that x-ray, and a final height. BA and CA were compared between races. PFH was calculated by dividing height at the time of the x-ray by their final height. To further evaluate differences between races in CA or BA, PFH was then modeled as a function of CA or BA using a fifth-degree polynomial regression, and mean ages at the 85th PFH were compared. Patients were then divided into Sanders stages 1, 2-4, and 5-8 and the mean PFH, CA, and BA of the Asian, Black, and Hispanic children were compared with the White children using Student t test. P values less than 0.05 were considered significant.

RESULTS

We studied 498 patients, including 53 Asian, 83 Black, 190 Hispanic, and 172 White patients. Mean BA was significantly greater than CA in Black males (1.27 y) and females (1.36 y), Hispanic males (1.12 y) and females (1.29 y), and White females (0.74 y). Hispanic and Black patients were significantly more advanced in BA than White patients (P<0.001). At the 85th PFH, White and Hispanic males were older than Black males by at least 7 months (P<0.001), and White females were significantly older than Hispanic females by 6.4 months (P<0.001). At 85th PFH for males, Hispanic and Black males had greater BA than White males by at least 5 months (P<0.001), and Asian females had a greater BA than Black females by at least 5 months (P<0.001). Compared with White children, Hispanic children were significantly younger at Sanders 2-4 than White children, and Black children were skeletally older at Sanders 5-8.

CONCLUSIONS

BA was greater than CA by ≥1 year in Black and Hispanic children, and that these children had a significantly greater BA than their White counterparts. Black males and Hispanic females reached their 85th PFH at younger ages, and Hispanic males and Asian females were the most skeletally mature at their 85th PFH. Our results suggest that BA and CA may vary as a function of race, and further studies evaluating growth via the 85th PFH may be necessary.

LEVEL OF EVIDENCE

Therapeutic Study - Level IV.

Growth in achondroplasia, from birth to adulthood, analysed by the JPA-2 model

OBJECTIVES

In general population, there are three phases in the human growth curve: infancy, childhood and puberty, with different main factors involved in their regulation and mathematical models to fit them. Achondroplasia children experience a fast decreasing growth during infancy and an "adolescent growth spurt"; however, there are no longitudinal studies that cover the analysis of the whole post-natal growth. Here we analyse the whole growth curve from infancy to adulthood applying the JPA-2 mathematical model.

METHODS

Twenty-seven patients, 17 girls and 10 boys with achondroplasia, who reached adult size, were included. Height growth data was collected from birth until adulthood. Individual growth curves were estimated by fitting the JPA-2 model to each individual's height for age data.

RESULTS

Height growth velocity curves show that after a period of fast decreasing growth velocity since birth, with a mean of 9.7 cm/year at 1 year old, the growth velocity is stable in late preschool years, with a mean of 4.2 cm/year. In boys, age and peak height velocity in puberty were 13.75 years and 5.08 cm/year and reach a mean adult height of 130.52 cm. In girls, the age and peak height velocity in puberty were 11.1 years and 4.32 cm/year and reach a mean adult height of 119.2 cm.

CONCLUSIONS

The study of individual growth curves in achondroplasia children by the JPA-2 model shows the three periods, infancy, childhood and puberty, with a similar shape but lesser in magnitude than general population.

Estimating peak height velocity in individuals: a comparison of statistical methods

BACKGROUND

Estimates pertaining to the timing of the adolescent growth spurt (e.g. peak height velocity; PHV), including age at peak height velocity (aPHV), play a critical role in the diagnosis, treatment, and management of skeletal growth and/or developmental disorders. Yet, distinct statistical methodologies often result in large estimate discrepancies.

AIM

The aim of the present study was to assess the advantages and disadvantages of three modelling methodologies for height as well as to determine how estimates derived from these methodologies may differ, particularly those that may be useful in paediatric clinical practice.

SUBJECTS AND METHODS

Height data from 686 individuals of the Fels Longitudinal Study were modelled using 5th order polynomials, natural cubic splines, and SuperImposition by Translation and Rotation (SITAR) to determine aPHV and PHV for all individuals together (i.e. population average) by sex and separately for each individual. Estimates within and between methodologies were calculated and compared.

RESULTS

In general, mean aPHV was earlier, and PHV was greater for individuals when compared to estimates from population average models. Significant differences between mean aPHV and PHV for individuals were observed in all three methodologies, with SITAR exhibiting the latest aPHV and largest PHV estimates.

CONCLUSION

Each statistical methodology has a number of advantages when used for specific purposes. For modelling growth in individuals, as one would in paediatric clinical practice, we recommend the use of the 5th order polynomial methodology due to its parameter flexibility.

Construction of a new growth references for China based on urban Chinese children: comparison with the WHO growth standards

Introduction

Growth references for Chinese children should be updated due to the positive secular growth trends and the progress of the smoothing techniques. Human growth differs among the various ethnic groups, so comparison of the China references with the WHO standards helps to understand such differences.

Methods

The China references, including weight, length/height, head circumference, weight-for-length/height and body mass index (BMI) aged 0–18 years, were constructed based on 69,760 urban infants and preschool children under 7 years and 24,542 urban school children aged 6–20 years derived from two cross-sectional national surveys. The Cole’s LMS method is employed for smoothing the growth curves.

Results

The merged data sets resulted in a smooth transition at age 6–7 years and continuity of curves from 0 to 18 years. Varying differences were found on the empirical standard deviation (SD) curves in each indicator at nearly all ages between China and WHO. The most noticeable differences occurred in genders, final height and boundary centiles curves. Chinese boys’ weight is strikingly heavier than that of the WHO at age 6–10 years. The height is taller than that of the WHO for boys below 15 years and for girls below 13, but is significantly lower when boys over 15 years and girls over 13. BMI is generally higher than that of the WHO for boys at age 6–16 years but appreciably lower for girls at 3–18 years.

Conclusions

The differences between China and WHO are mainly caused by the reference populations of different ethnic backgrounds. For practitioners, the choices of the standards/references depend on the population to be assessed and the purpose of the study. The new China references could be applied to facilitate the standardization assessment of growth and nutrition for Chinese children and adolescents in clinical pediatric and public health.

Vocal Cords-Carina Distance in Anaesthetised Caucasian Adults and its Clinical Implications for Tracheal Intubation

Previous work has assessed vocal cords-carina distance in Chinese patients and compared it to commonly used tracheal tubes. In addition, an attempt was made to identify surface anatomy measurements with short tracheas. We have examined the length of tracheas in Caucasian patients and compared it with currently used tracheal tubes. We have investigated a wider range of surface anatomy measurements in an attempt to correlate measurements with vocal cords-carina distance and identifying patients who may be at risk of endobronchial intubation. In this study, the vocal cords-carina distance was measured in 150 anaesthetised Caucasian patients with a fibreoptic bronchoscope. We also attempted to correlate height and various surface anatomy measurements on the patients’ chest, neck and limb regions to predict those patients at risk of endobronchial intubation. The mean vocal cords-carina distance was 12.7 cm (standard deviation 1.6 cm). The best predictors in our study of vocal cords-carina distance less than 11.3 cm were a height of ≤182 cm, an ulnar length of ≤31.2 cm or a thyroid to xiphisternum distance of ≤31.8 cm. This correlation is poor however, and prediction of vocal cords-carina distance remains difficult clinically. It was therefore concluded that surface anatomy measurements are a poor predictor of vocal cords-carina distance.

Interpopulation variation in height among children 7 to 18 years of age

The objective of this review is to examine the degree of variation that exists in the achieved height of preadolescent and adolescent children across populations experiencing favorable conditions that support linear growth. Fifty-three population groups were identified that reported mean heights for economically privileged populations from all major continents. Graphic representation of the heights for these populations indicates that the mean height of preadolescent children differs by 3 to 5 cm, whereas population means begin to diverge from the National Center for Health Statistics/World Health Organization (NCHS/WHO) reference at puberty, with most non-European populations falling to approximately 5 cm below the reference and northern European populations exceeding the reference by a similar amount. We conclude that the evidence for limited interpopulation variation in the height of preadolescents supports consideration of a single growth reference for children up to puberty, but the uncertainty of the causes of the divergence in achieved height during puberty requires further research in order to establish an appropriate adolescent growth reference.

Evaluation of the feasibility of international growth standards for school-aged children and adolescents

Development of an international growth standard for the screening, surveillance, and monitoring of school-aged children and adolescents has been motivated by two contemporaneous events: the global surge in childhood obesity and the release of a new international growth standard for infants and preschool children by the World Health Organization (WHO). If a prescriptive approach analogous to that taken by WHO for younger children is to be adopted for school-aged children and adolescents, several issues would have to be addressed regarding the universality of growth potential across populations and how to define optimal growth in children and adolescents. A working group concluded that subpopulations exhibit similar patterns of growth when exposed to similar external conditioners of growth. However, on the basis of available data, it cannot be ruled out that some of the observed differences in linear growth across ethnic groups reflect true differences in genetic potential rather than environmental influences. Therefore, the sampling frame for the development of an international growth standard for children and adolescents would have to include multiethnic sampling strategies designed to capture the variation in human growth patterns. A single international growth standard for school-aged children and adolescents could be developed with careful consideration of the population and individual selection criteria, study design, sample size, measurements, and statistical modeling of primary growth and secondary ancillary data. The working group agreed that existing growth references for school-aged children and adolescents have shortcomings, particularly for assessing obesity, and that appropriate growth standards for these age groups should be developed for clinical and public health applications.

Evaluation of the feasibility of international growth standards for school-aged children and adolescents

The development of an international growth standard for the screening, surveillance, and monitoring of school-aged children and adolescents has been motivated by 2 contemporaneous events, the global surge in childhood obesity and the release of a new international growth standard for infants and preschool children by the WHO. If a prescriptive approach analogous to that taken by WHO for younger children is to be adopted for school-aged children and adolescents, several issues need to be addressed regarding the universality of growth potential across populations and the definition of optimal growth in children and adolescents. A working group of experts in growth and development and representatives from international organizations concluded that subpopulations exhibit similar patterns of growth when exposed to similar external conditioners of growth. However, based on available data, we cannot rule out that observed differences in linear growth across ethnic groups reflect true differences in genetic potential rather than environmental influences. Therefore, the sampling frame for the development of an international growth standard for children and adolescents must include multiethnic sampling strategies designed to capture the variation in human growth patterns. A single international growth standard for school-aged children and adolescents could be developed with careful consideration of the population and individual selection criteria, study design, sample size, measurements, and statistical modeling of primary growth and secondary ancillary data. The working group agreed that existing growth references for school-aged children and adolescents have shortcomings, particularly for assessing obesity, and that appropriate growth standards for these age groups should be developed for clinical and public health applications.

Age- and sex-specific body composition of Chinese children

We examined age- and sex-specific body compositions of Chinese children by the bioelectrical impedance method. The subjects were a total of 587 children aged 6-14 y who had normal relative weight. In all ages, boys had larger fat-free mass and lower percent body fat (%BF) than girls did. Even in the subjects with BMI <20 kg/m2, more than one quarter of them had high %BF.

CONCLUSION

Chinese children may have higher %BF than that predicted by BMI.

Morphological growth and thorax dimensions among Tibetan compared to Han children, adolescents and young adults born and raised at high altitude

BACKGROUND

Studies comparing the growth of indigenous high-altitude Aymara children and children of low-altitude European descent who have been born and raised at high altitude in the Andes have provided evidence for genetically-determined differences in thorax growth, as well as for population differences in height, weight and other measures of overall size. Comparable studies now can be undertaken in Asia because of the growing number of Han Chinese who have been born and raised at high altitude on the Qinghai-Tibetan Plateau.

AIM

The study compares the growth of indigenous Tibetan children and children of Han descent who have been born and raised at the same high altitudes, and under similar socio-economic conditions.

SUBJECTS AND METHODS

Measurements of stature, sitting height, weight, triceps and subscapular skinfolds, upper arm muscle area, transverse chest diameter, anterio-posterior chest diameter, and chest circumference were taken on 1439 Tibetan and Han males and females between the ages of 6 and 29 years who were born and raised 3200 m, 3800 m or at 4300 m in the high altitude province of Qinghai in western China.

RESULTS

Han-Tibetan differences in body size do not occur systematically for any measurement, for any age group, or for either gender; nor is there a systematic pattern of body size differences between 3200 m and 4300 m. This indicates that there are no differences in general growth between the two groups at high altitude in Qinghai, although both groups grow more slowly than urban children at low altitude in China. On the other hand, Tibetan males possess significantly deeper chests than Han males, and Tibetan females possess significantly wider chests than Han females. Tibetans of both sexes possess significantly larger chest circumferences than Han males and females.

CONCLUSIONS

Although genetic similarities cannot be ruled out, comparable dietary stress is a likely explanation for the similar and slow morphological growth of Han and Tibetans at high altitude. However, Han-Tibetan differences in thorax dimensions are likely a consequence of population (genetic) differences in the response to hypoxia during growth.

Growth of Han migrants at high altitude in central Asia

Han Chinese of low-altitude descent have been living in Qinghai Province of Western China for at least two millennia. For most of this time they have lived at elevations under 2,500 m. However, during the last four decades an increasing number of Han have moved into high-altitude towns at elevations over 3,000 m, and some above 4,000 m. There are now sufficient numbers of Han descendants who have been born and raised at high altitude to allow a comparison of their morphological and physiological growth patterns with low-altitude Han to detect the effect of hypoxia. The field study reported here was conducted by collaborating Chinese and American researchers over a 6-year period, and included 1,227 Han living at high altitude in Qinghai and at low altitude near Beijing. This study demonstrates that Han born and raised at high altitude are smaller and lighter than those at low altitude-particularly as children and adolescents. Slower growth at high altitude may be a consequence of hypoxia, but it also corresponds to poorer economic conditions in rural Qinghai Province, and thus may reflect nutritional inadequacies. Differences in altitude and/or nutrition do not seem to affect thorax dimensions, since, relative to stature, chest dimensions are similar at both high and low altitudes. Nevertheless, lung volumes are higher among Han at high altitude, possibly reflecting the influence of hypoxia on alveolar growth. The hematological values of Han growing up at 3,200 m are not different from those at low altitude-an unusual finding relative to other low-altitude groups that may reflect population differences in response to hypoxia. At 3,800 m and 4,300 m, however, Han show elevated hemoglobin relative to Han at low altitude.

Height of young men

We analysed the height of young men in Belgium, using 613 257 records of medical examinations made prior to their conscription into the army (about 68% of the male population concerned). All analyses showed very significant associations. Height differed according to the region (-1.24cm in Wallonia, French-speaking and poorer) compared to Flanders (Dutch-speaking and richer), when "age-class" and year are taken into account. The smallest men lived in Hainaut (a deprived area), the tallest ones in Walloon Brabant (wealthy green suburbs of the capital). Height increased across time (+1.11cm, 1978-1990) and with "age-class" (+2.66cm, 18-26years), controlling for other factors. The increase in Brussels stops in 1983, probably due to other socio-demographic evolutions.

Body fat ratios in urban Chinese children

OBJECTIVE

As obesity has been increasing in China, the present study examined the body composition of children to assess their fatness.

STUDY DESIGN

A total of 532 healthy schoolchildren who lived in central Beijing were examined. Skinfold thicknesses, hip and waist circumferences, and body fat percentage were measured, as well as height and weight.

RESULTS

The prevalence of overweight (Body Mass Index (BMI) >or= 95% for age and sex of Chinese children) was 27.7% in boys and 14.2% in girls (chi-squared; P = 0.0001). The percentages of body fat (BF%), waist/hip ratios and skinfold thicknesses ratios (subscapular/triceps) in overweight children were significantly higher than those in non-overweight children (Mann-Whitney U-test). The BF% of non-overweight boys was significantly higher than that of non-overweight girls.

CONCLUSION

Urban Chinese overweight children have high BF% with adverse fat distribution. They may have high risk of atherogeniety. Boys in the non-overweight category may have higher fat accumulation than predicted by BMI. The establishment of an intervention program for childhood obesity is strongly recommended.

Simple method for developing percentile growth curves for height and weight

The present paper demonstrates the ease of use of method I by Preece and Baine ([1978] Ann Hum Biol 5:1-24) in generating smoothed growth curves for both height and weight. Using the National Center for Health Statistics (NCHS) growth curve data, smoothed curves were developed and compared to those produced using the least-squares-cubic-spline method. Based on the lower sum of squares and better fit of shape as indicated by residual examination, it was concluded that the method I curve fitting procedure by Preece and Baine ([1978] Ann Hum Biol 5:1-24) fit centile growth curves for height and weight in 2-18-year-old male and female children as well as, if not better than, the least-squares-cubic-spline method used in developing the 1979 NCHS growth curves. Further, as this paper demonstrates, smoothed curves can be generated on a desktop computer using readily available software (the SOLVER function within Microsoft EXCEL).

Morphological growth of Han boys and girls born and raised near sea level and at high altitude in western China

This study compares the morphological characteristics of Han children, adolescents, and young adults who were born at 250 m near Beijing and at three high altitudes in Qinghai Province, Peoples Republic of China (3,200 m, 3,800 m, and 4,300 m). From ages 6 through 15, Han children growing up at high altitudes are significantly shorter, lighter, have less fat, and are less muscular than Han children growing up at low altitude. However, older adolescents and young adults show no such altitude differences. Younger adolescents and children in this study were all born after the government economic reforms of 1978. These reforms had a greater impact on the growth of children in and around large cities than on those in more remote areas. Therefore, the altitude differences in size among Han children ages 15 and younger may be a consequence of regional variation in health and nutrition, rather than due to the influence of hypoxia. There are no altitude-related differences in thorax dimensions among Han children, adolescents, or young adults. This suggests that hypoxia does not affect the thorax growth of Han children. Am. J. Hum. Biol. 12:665-681, 2000. Copyright 2000 Wiley-Liss, Inc.