Validation of growth standards and growth references: A review of literature

Disparities with global standards about growth references of mid-upper arm circumference-for-age for Pakistani children aged 6-60 months

AIM

Growth reference values about mid-upper arm circumference (MUAC) are vital for assessing children's nutritional status. However, Pakistan lacks these reference values and growth charts. This study aims to develop these for children aged 6-60 months and compare them with global standards.

METHODS

The data were acquired from the 2018 National Nutrition Survey of Pakistan, which was conducted by the United Nations Children's Fund (UNICEF) during 2018-2019. The final study cohort comprised 57 285 children, with 51% being boys. Percentile values and charts for MUAC-for-age were developed using generalised additive models for location, scale and shape with the Box-Cox power exponential distribution.

RESULTS

The mean MUAC was 14.21 cm (±2.07 cm) and 14.13 cm (±2.12 cm) for the boys and girls, respectively. At 60 months of age, the P3 and P97 percentiles for girls were slightly higher than those for boys. The median percentiles of Pakistani children were smaller than the World Health Organisation 2007 standards and with international references.

CONCLUSION

We observed disparities in MUAC-for-age growth references among Pakistani children compared to global standards, highlighting regional, age and gender variations. This underscores the need for developing countries like Pakistan to establish their growth references.

Evaluating the Validity of International Standards of Height, Weight, and Body Mass Index on Jordanian Children and Adolescents

BACKGROUND

the variations in a child's overall body shape and figure among different countries are attributable to differences in genetics, environmental factors, and the interaction between these elements. This study aims to evaluate the validity, reliability, and appropriateness of applying international growth standards to Jordanian children and adolescents aged 2-19 years old.

METHODS

65,828 Jordanian children and adolescents (43% males; 57% females) aged 2-19 years old were selected from the Hakeem Program database and various private schools across Jordan. Height-for-age, weight-for-age, and body mass index (BMI)-for-age were analyzed comparatively for Jordanian children and adolescents against international growth standards. The z-score for each record was computed based on international equations.

RESULTS

Mean z-scores for height-for-age, weight-for-age, and BMI-for-age for both genders showed significant deviation from international standards across most age intervals. It was found that in most age groups, Jordanian children and adolescents were shorter and lighter than CDC and WHO standards, except for females at ages ≥ 16 years, who were heavier with higher BMI-for-age values than CDC standards based on weight-for-age and BMI-for-age equations. Moreover, Jordanian males at ages ≥ 12 years had lower BMI-for-age values than CDC standards.

CONCLUSIONS

Jordanian children and adolescents showed significant deviations in their measurements from international standards and growth reference values. The development of a population-specific growth chart is highly recommended to enhance the accuracy of evaluating children's and adolescents' wellness.

Evaluation of the safety and efficacy of biosimilar recombinant growth hormone in children with growth hormone deficiency: non-inferiority, randomized, parallel, multicentric and Phase III trial

OBJECTIVES

This study is designed in order to compare the efficacy and safety of recombinant human growth hormone (rhGH) with the reference brand.

METHODS

According to the inclusion criteria, 85 people in 13 Iranian centers were randomly selected to receive biosimilar Somatropin (Somatin®) (44 people) and reference Somatropin (Norditropin®) (41 people) at a dose of 35 µg/kg/d, seven days/week for 12 months. The primary outcomes included height velocity (HV) was measured during 12 months of treatment.

RESULTS

The two intervention groups' Height changes were similar. The mean HV was 10.96 cm/year in the biosimilar group and 10.05 cm/year in the reference groups after 12 months. Estimates of the lower bounds of 95% CI for mean height differences in the biosimilar intervention group compared to the reference intervention group did not exceed the 2 cm margin. Therefore, the non-inferiority of biosimilar intervention compared to the brand product is verified. Common ADRs in both groups were nausea in two patients (2.4%), diarrhea in two patients (2.4%), increased body temperature in one patient (1.2%), and headache in one patient (1.2%).

CONCLUSIONS

The finding of this study indicated that Somatin® and Norditropin® have comparable efficacy and safety profiles.

CLINICAL TRIAL REGISTRATION

www.IRCT.irIRCT20171122037571N1.

Global relevance of MGRS growth standards: the case of India

The most common measures of childhood undernutrition are based on anthropometric measures such as height-for-age (stunting/chronic undernutrition) and weight-for-height (wasting/acute undernutrition). It is well recognised that the determinants of undernutrition are multiple, including food intake, dietary diversity, health, sanitation and women's status. Currently, most countries across the world including India use the globally accepted WHO-Multicentre Growth Reference Study (MGRS) growth standards (2006) for the purposes of measurement as well as for evaluating progress on these metrics. However, there is some discussion on the universal relevance of these standards, and in the Indian context, whether these standards overestimate the prevalence of stunting, considering differences in genetic potential for growth. This is especially relevant in the context of increasing burden of obesity and non-communicable diseases in India. Based on a detailed review of literature, policy documents and expert inputs, this review paper discusses the relevance of the WHO growth standards for height/stunting, in the context of India. Issues discussed related to the MGRS methodology include pooling of data and intersite and intrasite variability, opting for standards as opposed to references, and external validity. Other issues related to plasticity of stunting and the influence of maternal heights are also discussed, in the context of analysing the appropriateness of using universal growth standards. Based on the review, it is recommended that the current standards may continue to be used until a newer global standard is established through a similar study.

Development of a Zimbabwean child growth curve and its comparison with the World Health Organization child growth standards

Background

There is limited research that describes the growth trajectories of African children. The development of World Health Organization (WHO) growth standards considered a sample of children who lived in environments optimum for human growth.

Aim

This study aimed to develop weight-for-age and height-for-age growth curves from the Zimbabwean 2018 National Nutrition Survey and compare them with the WHO growth standards.

Setting

Study participants were recruited from all districts in Zimbabwe.

Methods

Height-for-age and weight-for-age data collected from 32 248 children were used to develop the Zimbabwean references. Smooth growth curves (height, weight and body mass index [BMI]-for-age) were estimated with the Lambda Mu Sigma (LMS) method and compared with the WHO growth standards.

Results

Zimbabwean children were shorter and weighed less in comparison with the WHO growth standards. The –2 standard deviation (s.d.) Z-score curves (height-for-age) for Zimbabwean children (boys and girls) were below the –1 s.d. Z-score curves of the WHO growth standards. The Zimbabwean Z-scores (BMI-for-age) values above –1 s.d. were significantly higher in comparison with the corresponding WHO growth standards.

Conclusion

Utilising the WHO growth standards would diagnose a higher proportion of Zimbabwean children as stunted whilst underestimating the proportion at risk of obesity. The WHO growth standards lack a consideration of the geographical, economic, political and environmental constraints existing between countries.