Genetic Determinants of Prepubertal and Pubertal Growth and Development

Which Factors Influence Running Gait in Children and Adolescents? A Narrative Review

In recent years, running has dramatically increased in children and adolescents, creating a need for a better understanding of running gait in this population; however, research on this topic is still limited. During childhood and adolescence multiple factors exist that likely influence and shape a child's running mechanics and contribute to the high variability in running patterns. The aim of this narrative review was to gather together and assess the current evidence on the different factors that influence running gait throughout youth development. Factors were classified as organismic, environmental, or task-related. Age, body mass and composition, and leg length were the most researched factors, and all evidence was in favour of an impact on running gait. Sex, training, and footwear were also extensively researched; however, whereas the findings concerning footwear were all in support of an impact on running gait, those concerning sex and training were inconsistent. The remaining factors were moderately researched with the exception of strength, perceived exertion, and running history for which evidence was particularly limited. Nevertheless, all were in support of an impact on running gait. Running gait is multifactorial and many of the factors discussed are likely interdependent. Caution should therefore be taken when interpreting the effects of different factors in isolation.

Regional variation in growth status. The Peruvian health and optimist growth study

OBJECTIVE

This study aims to (1) investigate differences in weight, body mass index (BMI), and waist circumference (WC) among Peruvian children and adolescents living in three areas located at different altitudes; (2) compare age- and sex-specific height, weight, and BMI within each site with US reference data.

METHODS

We sampled 8753 subjects (4130 boys), aged 4 to 17 years from sea level, rainforest, and high-altitude. Height, weight, and WC were measured and BMI was calculated. Analysis of variance was used to compare variables across geographic regions, and the Hoff and Blackburn procedure was used to compare the Peruvian results with US reference data.

RESULTS

Participants living at sea level were taller, heavier, had greater BMI and WC relative to those living at high-altitude and in the rainforest. Peruvian schoolchildren of both sexes from the three geographical areas were shorter and lighter than their American peers. Boys and girls living in the rainforest and at high-altitude had lower BMI, whereas WC values of American schoolchildren are higher than those of the Peruvian children by age and gender.

CONCLUSIONS

Peruvians living at different altitudes differ in their growth indicators (height, weight, BMI, and WC), with significant differences between those living at sea level relative to their peers from other regions. Further, Peruvian schoolchildren of both sexes from the three geographical areas significantly differ from their US counterparts.

Are the Growth Standards of the World Health Organization Valid for Spanish Children? The SONEV Study

Background: The use of different growth tables to assess the population's nutritional status has given rise to a series of limitations arising from the lack of consensus and uniform methodological criteria. This leads to a disparity of results that prevent an accurate and reliable diagnosis of whether a child is overweight or obese. Objective: The purpose of this study was to develop growth references for weight, height, and body mass index for Eastern-Spanish children from 6 to 16 years of age. Methods: The final sample used to fit the growth curves was made up of 1,102 observations. The 2007 WHO curves are currently used for Child Health Service Cards. Therefore, to make the comparison of the internal values obtained as realistic as possible, the same construction method has been used for the internal curves, modeling age as a continuous variable and simultaneously adjusting the curves, smoothing them using cubic splines and further smoothing the edge effects by means of data extending above or below the upper and lower age limits. Results: Growth curves for percentiles were constructed for both sexes and higher values were noticeably found to set as growth-standard compared to WHO-standards. Conclusion: Our analysis shows that the WHO 2007 standard references are not suitable for Eastern-Spanish children. The standards shown in this study are much more realistic and current, and we believe that their use will help healthcare professionals more effectively combat the current epidemic of overweight and obesity.

Genetic Polymorphisms Associated with Idiopathic Short Stature and First-Year Response to Growth Hormone Treatment

BACKGROUND/AIMS

The term idiopathic short stature (ISS) describes short stature of unknown, but likely polygenic, etiology. This study aimed to identify genetic polymorphisms associated with the ISS phenotype, and with growth response to supplemental GH.

METHODS

Using a case-control analysis we compared the prevalence of "tall" versus "short" alleles at 52 polymorphic loci (17 in growth-related candidate genes, 35 identified in prior genome-wide association studies of adult height) in 94 children with ISS followed in the Genetics and Neuroendocrinology of Short Stature International Study, versus 143 controls from the Fels Longitudinal Study.

RESULTS

Four variants were nominally associated with ISS using a genotypic model, confirmed by a simultaneous confident inference approach: compared with controls children with ISS had lower odds of "tall" alleles (odds ratio, 95% CI) for GHR (0.52, 0.29-0.96); rs2234693/ESR1 (0.50, 0.25-0.98); rs967417/BMP2 (0.39, 0.17-0.93), and rs4743034/ZNF462 (0.40, 0.18-0.89). Children with ISS also had lower odds of the "tall" allele (A) at the IGFBP3 -202 promoter polymorphism (rs2855744; 0.40, 0.20-0.80) in the simultaneous confident inference analysis. A significant association with 1st-year height SD score increase during GH treatment was observed with rs11205277, located near 4 known genes: MTMR11, SV2A, HIST2H2AA3, and SF3B4; the latter, in which heterozygous mutations occur in Nager acrofacial dysostosis, appears the most relevant gene.

CONCLUSIONS

In children with ISS we identified associations with "short" alleles at a number of height-related loci. In addition, a polymorphic variant located near SF3B4 was associated with the GH treatment response in our cohort. The findings in our small study warrant further investigation.

Low Habitual Dietary Calcium and Linear Growth from Adolescence to Young Adulthood: results from the China Health and Nutrition Survey

Evidences from clinical trials and meta-analyses of calcium supplementation in linear growth have given conflicting results, and few longitudinal studies have investigated the long-term associations between dietary calcium and linear growth, especially in the population with low-calcium plant-based diets. We investigated the prospective associations of low habitual dietary calcium with adult height and height-for-age z-score (HAZ) from adolescence to adulthood among 2019 adolescents from the China Health and Nutrition Survey (CHNS). The average dietary calcium intakes were 426(standard deviation: 158) mg/d in boys and 355(134) mg/d in girls during adolescence. During a median follow-up of 7.0 (interquartile range: 5.9–9.0) years, boys reached an average of 169.0(6.7) cm and girls reached 158.4(5.8) cm in adulthood. After adjusting for other potential confounders, non-linear regression found that boys with dietary calcium intakes below 327 mg/d had shorter adult stature, and those taking over 566 mg/d had faster height growth whether adjusting for physical exercises level or not. No significant associations were found in girls. Our study suggests that in boys with plant-based diets, higher dietary calcium intake during adolescence is associated with faster height growth, but not with adult height; calcium intake below 300 mg/d may result in shorter adult stature.

Indicators of Biological Maturation and Secular Changes in Biological Maturation

Commonly used indicators of biological maturation are discussed, including sexual, skeletal, morphological, and dental maturity, and the hypothalamus–pituitary–end organ axes that regulate the growth and maturation processes. Interrelationships among indicators and the tempo, timing, and sequence of maturational events are also considered. Environmental factors that influence the level of maturity at a given point in time and the process of maturation are also discussed: undernutrition, obesity, ethnic/racial background, social class, familial characteristics, climate, and altitude. Recommendations for the design of studies of maturational events are made, and an overview of secular changes before and after 1970 is provided. The review concludes with specific recommendations for the inclusion of a maturity indicator or maturity indicators in the construction of an international growth standard for preadolescent and adolescent children

Early Childhood Father Absence and Depressive Symptoms in Adolescent Girls from a UK Cohort: The Mediating Role of Early Menarche

Absence of the biological father in early childhood has been linked to depressive symptoms in mid-adolescent girls. Earlier studies have linked father absence to early timing of menarche, and early menarche is a risk factor for increased depressive symptoms in adolescence. No studies, however, have examined whether the association between father absence and depressive symptoms may be explained by the early onset of menarche. This study investigated whether age at menarche mediates the association between father absence in early childhood (birth to 5 years) and depressive symptoms in adolescent girls aged 14 years. The study sample comprised 7056 girls from a large UK birth cohort (Avon Longitudinal Study of Parents and Children) who provided data on age at onset of menarche and depressive symptoms assessed using the Short Mood and Feelings Questionnaire at 14 years. Mothers provided data on father absence from the birth of the study child up to 10 years. Using structural equation modelling, we found that 15 % of the total estimated association between father absence in early childhood and depressive symptoms at 14 years was explained by early age at menarche. In addition to the mediated effect, father absence was linked to an 11 % increase in depressive symptoms in adolescence. The findings suggest that early age at menarche is one of the pathways linking early childhood father absence and depressive symptoms in mid-adolescent girls. Preventive strategies could be targeting young girls at risk for depressive symptoms as a function of stressful family factors (e.g., biological father absence) and earlier menarche.

Centile curves and reference values for height, body mass, body mass index and waist circumference of Peruvian children and adolescents

This study aimed to provide height, body mass, BMI and waist circumference (WC) growth centile charts for school-children, aged 4-17 years, from central Peru, and to compare Peruvian data with North-American and Argentinean references. The sample consisted of 8753 children and adolescents (4130 boys and 4623 girls) aged 4 to 17 years, from four Peruvian cities: Barranco, La Merced, San Ramón and Junín. Height, body mass and WC were measured according to standardized techniques. Centile curves for height, body mass, BMI and WC were obtained separately for boys and girls using the LMS method. Student t-tests were used to compare mean values. Overall boys have higher median heights than girls, and the 50th percentile for body mass increases curvilinearly from 4 years of age onwards. In boys, the BMI and WC 50th percentiles increase linearly and in girls, the increase presents a curvilinear pattern. Peruvian children are shorter, lighter and have higher BMI than their counterparts in the U.S. and Argentina; in contrast, age and sex-specific WC values are lower. Height, body mass and WC of Peruvian children increased with age and variability was higher at older ages. The growth patterns for height, body mass, BMI and WC among Peruvian children were similar to those observed in North-American and Argentinean peers.

Weight and height centiles of Argentinian children and adolescents: a comparison with WHO and national growth references

BACKGROUND

Studies in several countries comparing the performance of WHO references and their own national growth standards reported differences that could affect screening and growth monitoring.

AIM

To estimate weight and height centiles on a sample of Argentinian children and adolescents and compare selected centiles with WHO and national growth references.

SUBJECTS AND METHODS

A cross-sectional school survey was conducted on 6239 boys and girls aged 5-18. Data were collected between 2005-2009 in Santa Rosa, Argentina. Smoothed weight and height centiles were estimated by the LMS method and compared with WHO 2007 and Argentinian (ARG) growth references.

RESULTS

Weight centiles were higher than those of WHO and ARG. Height centiles were above the ARG and below the WHO ones. The greatest differences with ARG were seen before puberty and then declined up to age 18. In contrast, differences with WHO increased from puberty onwards.

CONCLUSION

Compared with the ARG reference, linear growth of these schoolchildren shows a secular acceleration without substantial improvements in the adult height. In relation to WHO, the results suggest that around the adolescent growth spurt differences in linear growth between populations became larger, limiting the clinical usefulness of international growth references in adolescents.

Evaluation of nutritional status in Turkish adolescents as related to gender and socioeconomic status

OBJECTIVE

To evaluate the nutritional status of Turkish high school adolescents using anthropometric indicators and to determine the relationship of nutritional status with gender and socioeconomic status (SES) in adolescents.

METHODS

Six hundred eighty adolescent students (n=284 males, 396 females) aged 14-18 years were selected from 6 high schools of different regions. Nutritional status was evaluated according to the anthropometric indicators, which were based on the WHO criteria. Adolescents were grouped into three SES categories.

RESULTS

The rates of being stunted, underweight, and overweight/obesity were 4.4%, 5.0% and 16.8%, respectively. Height and weight standard deviation scores (SDS) were significantly lower in adolescents with low SES (p<0.05). The frequency of stunting was significantly higher in adolescents with low SES (p=0.012). Frequency of underweight, overweight and obesity did not differ significantly between socioeconomic groups and genders (p>0.05).

CONCLUSION

Adolescents of low SES were shorter and thinner than those of other SES categories. Undernutrition needs to be addressed in low SES. Among all Turkish adolescents, the major nutritional problems were overweight and obesity. There were no SES and gender differences in prevalence of overweight and obesity among the Turkish school adolescents living in urban areas. Prevalence of obesity is rising, regardless of differences in SES and gender, in developing countries too.

Genetic determinants of height growth assessed longitudinally from infancy to adulthood in the northern Finland birth cohort 1966

Recent genome-wide association (GWA) studies have identified dozens of common variants associated with adult height. However, it is unknown how these variants influence height growth during childhood. We derived peak height velocity in infancy (PHV1) and puberty (PHV2) and timing of pubertal height growth spurt from parametric growth curves fitted to longitudinal height growth data to test their association with known height variants. The study consisted of N = 3,538 singletons from the prospective Northern Finland Birth Cohort 1966 with genotype data and frequent height measurements (on average 20 measurements per person) from 0–20 years. Twenty-six of the 48 variants tested associated with adult height (p<0.05, adjusted for sex and principal components) in this sample, all in the same direction as in previous GWA scans. Seven SNPs in or near the genes HHIP, DLEU7, UQCC, SF3B4/SV2A, LCORL, and HIST1H1D associated with PHV1 and five SNPs in or near SOCS2, SF3B4/SV2A, C17orf67, CABLES1, and DOT1L with PHV2 (p<0.05). We formally tested variants for interaction with age (infancy versus puberty) and found biologically meaningful evidence for an age-dependent effect for the SNP in SOCS2 (p = 0.0030) and for the SNP in HHIP (p = 0.045). We did not have similar prior evidence for the association between height variants and timing of pubertal height growth spurt as we had for PHVs, and none of the associations were statistically significant after correction for multiple testing. The fact that in this sample, less than half of the variants associated with adult height had a measurable effect on PHV1 or PHV2 is likely to reflect limited power to detect these associations in this dataset. Our study is the first genetic association analysis on longitudinal height growth in a prospective cohort from birth to adulthood and gives grounding for future research on the genetic regulation of human height during different periods of growth.

Family studies have shown that adult height is largely genetically determined. Identification of common genetic factors has been expedited with recent advances in genotyping techniques. However, factors regulating childhood height growth remain unclear. We investigated genetic variants of adult height for associations with peak height velocity in infancy (PHV1) and puberty (PHV2) and timing of pubertal growth spurt in a population based sample of 3,538 Finns born in 1966. Most variants studied associated with adult height in this sample. Of the 48 genetic variants tested, seven of them associated with PHV1 and five with PHV2. However, only one of these associated with both, and we found suggestive evidence for differential effects at different stages of growth for some of the variants. In this sample, less than half of the variants associated with adult height had a measurable effect on PHV1 or PHV2. However, these differences may reflect lower statistical power to detect associations with height velocities compared to adult height. This study provides a foundation for further biological investigation into the genes acting at each stage of height growth.

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.