Height, weight and body mass index percentiles of children aged 6-14 years living at moderate altitudes

Influence of ecoregional and lifestyle factors on growth and body composition of I ndian children and adolescents aged 9–18 years—A multicenter study

OBJECTIVES

Ecoregion comprises all the environmental factors such as climate, vegetation, geomorphology, and soil taken together. The objectives of this study were to (1) assess differences in growth and body composition (BC) in 9-18-year-old children and adolescents (CA), across six ecoregions of India, (2) evaluate and compare the magnitude of the effect of ecoregional and lifestyle factors (LSF) on growth and BC in urban (U) and rural (R) children and adolescents, and (3) reassess the applicability of Bergmann's Rule and Allen's Rule to humans.

SUBJECTS AND METHODS

Data on 1845 CA (925 boys; 920 girls) were collected (2016-2017) from urban and rural areas of six ecoregions of India. Anthropometric and BC parameters were measured; Z-scores were computed. Lifestyle Index score (LIS) based on LSF-(socioeconomic status [SES], diet, physical activity) was computed (categorized as low, medium, high-indicates better LSF). Univariate analysis was performed to estimate effect size.

RESULTS

Significant differences were observed in growth and BC across urban and rural ecoregions. CA with high LIS were taller and heavier than those with low LIS (p < .05). Ecoregion had greater effect on growth (Partial eta square (η² ) for R = 0.136 vs. U = 0.057) and BC (η² for R = 0.094 vs. U = 0.058) of rural CA than urban (p < .01). LSF had more effect on the BC of urban CA (η²  = 0.017) than rural (η²  = 0.002, p < .01).

CONCLUSION

Disparities among the six ecoregions were not large enough to fully support Bergmann's Rule and Allen's Rule. Ecoregion had greater effect on growth and BC of rural CA than urban, while lifestyle factors had more effect on the BC of urban CA.

Physical growth and body adiposity patterns in children and adolescents at high altitudes in Peru: Proposed percentiles for assessment

OBJECTIVES

This study's purpose was to compare physical growth (PG) patterns of children and adolescents living at high elevations with those of other geographic regions, relate body adiposity indicators, and develop percentile reference tables for assessing physical growth and body adiposity.

METHODS

The sample included 1536 children and adolescents ages 5.0 to 17.9 years from Puno (Peru) located between 3821 and 4349 m above sea level. Weight, height, arm and waist circumferences (WC), and three skinfolds measurements were recorded. Body mass index (BMI) and waist-height Index (WHI) were calculated.

RESULTS

PG patterns for children living at a high altitude reflected similar values for weight, height, and arm circumference (AC) to those of their counterparts living in Puno (Peru) and La Paz (Bolivia). When compared with children living at moderate altitudes in Peru, they showed slightly lower PG values. BMI explained between 41% and 64% of the variance in sum of the skinfolds, while WC explained between 47% and 66%. HWI was not a strong predictor of variation in sum of skinfolds. Percentiles were generated for WC and the sum of skinfolds.

CONCLUSION

Weight, height, and, arm and waist circumference patterns for children and adolescents living at high altitudes were similar to those of La Paz (Bolivia). WC and the sum of the skinfolds were better indicators for analyzing abdominal obesity compared to BMI and WHI. The percentiles proposed may be a useful tool for identifying high risk of developing overweight disorders in pediatric populations living at high altitudes.

Development of a New Growth Standard for Breastfed Chinese Infants: What Is the Difference from the WHO Growth Standards?

The objectives of this longitudinal study were to examine the trajectory of breastfed infants' growth in China to update growth standards for early childhood, and to compare these updated Chinese growth standards with the growth standards recommended by the World Health Organization (WHO) in 2006.This longitudinal cohort study enrolled 1,840 healthy breastfed infants living in an "optimal" environment favorable to growth and followed up until one year of age from 2007 to 2010. The study subjects were recruited from 60 communities in twelve cities in China. A participating infant's birth weight was measured within the first hour of the infant's life, and birth length and head circumference within 24 hours after birth. Repeated weekly and monthly anthropometric measurements were also taken. Multilevel (ML) modelling via MLwiN2.25 was fitted to estimate the growth curves of weight-for-age (WFA), length-for-age (LFA), and head circumference-for-age (HFA) for the study sample as a whole and by child sex, controlling for mode of delivery, the gravidity and parity of the mother, infant's physical measurements at birth, infant's daily food intaking frequency per day, infant's medical conditions, the season when the infant's physical measurement was taken, parents' ages, heights, and attained education, and family structure and income per month. During the first four weeks after birth, breastfed infants showed an increase in weight, length, and head circumference of 1110g, 4.9 cm, and 3.2 cm, respectively, among boys, and 980 g, 4.4 cm, and 2.8 cm, respectively, among girls. Throughout infancy, the total growth for these three was 6930 g, 26.4 cm, and 12.5 cm, respectively, among boys, and 6480 g, 25.5 cm, and 11.7 cm, respectively, among girls. As expected, there was a significant sex difference in growth during the first year. In comparison with the WHO growth standards, breastfed children in our study were heavier in weight, longer in length, and bigger in head circumference, with the exception of a few age points during the first two to four months on the upper two percentile curves.Our data suggested the growth curves for breastfed infants in China were significantly different in comparison with those based on the WHO standards. The adoption of the WHO infant growth standards among Chinese infants, as well as the methods used in the development of such growth standards in China, need careful and coordinated consideration.

Genetic and phenotypic differentiation of an Andean intermediate altitude population

Highland populations living permanently under hypobaric hypoxia have been subject of extensive research because of the relevance of their physiological adaptations for the understanding of human health and disease. In this context, what is considered high altitude is a matter of interpretation and while the adaptive processes at high altitude (above 3000 m) are well documented, the effects of moderate altitude (below 3000 m) on the phenotype are less well established. In this study, we compare physiological and anthropometric characteristics as well as genetic variations in two Andean populations: the Calchaquíes (2300 m) and neighboring Collas (3500 m). We compare their phenotype and genotype to the sea-level Wichí population. We measured physiological (heart rate, oxygen saturation, respiration rate, and lung function) as well as anthropometric traits (height, sitting height, weight, forearm, and tibia length). We conducted genome-wide genotyping on a subset of the sample (n = 74) and performed various scans for positive selection. At the phenotypic level (n = 179), increased lung capacity stood out in both Andean groups, whereas a growth reduction in distal limbs was only observed at high altitude. At the genome level, Calchaquíes revealed strong signals around PRKG1, suggesting that the nitric oxide pathway may be a target of selection. PRKG1 was highlighted by one of four selection tests among the top five genes using the population branch statistic. Selection tests results of Collas were reported previously. Overall, our study shows that some phenotypic and genetic differentiation occurs at intermediate altitude in response to moderate lifelong selection pressures.

Anthropometric studies on the Turkish population--a historical review

A historical review of anthropometric studies conducted on Turkish children and adults is presented. In view of observed differences in growth status between children of different societies, the need for local reference standards and the methodology to be used for such studies have been stressed. The importance of local studies in reflecting the state of health and nutrition both in children and adults has also been mentioned. While a number of studies in children cited in this paper are designed to compare the growth of children from different socioeconomic levels, other studies aim to establish local reference data for Turkish children. While the historical studies in adults aim to define racial characteristics, the more recent studies aim to bring out nutritional characteristics with emphasis on increasing frequency of obesity.