Assessment of sex differences and heterogeneity in motor milestone attainment among populations in the WHO Multicentre Growth Reference Study

Aim: To assess the heterogeneity of gross motor milestone achievement ages between the sexes and among study sites participating in the WHO Multicentre Growth Reference Study (MGRS). Methods: Six gross motor milestones (sitting without support, hands-and-knees crawling, standing with assistance, walking with assistance, standing alone, and walking alone) were assessed longitudinally in five of the six MGRS sites, namely Ghana, India, Norway, Oman and the USA. Testing was started at 4 mo of age and performed monthly until 12 mo, and bimonthly thereafter until all milestones were achieved or the child reached 24 mo of age. Four approaches were used to assess heterogeneity of the ages of milestone achievement on the basis of sex or study site. Results: No significant, consistent differences in milestone achievement ages were detected between boys and girls, nor were any site–sex interactions noted. However, some differences among sites were observed. The contribution of inter-site heterogeneity to the total variance was <5% for those milestones with the least heterogeneous ages of achievement (hands-and-knees crawling, standing alone, and walking alone) and nearly 15% for those with the most heterogeneous ages of achievement (sitting without support, standing with assistance, and walking with assistance).

Conclusion: Inter-site differences, most likely due to culture-specific care behaviours, reflect normal development among healthy populations across the wide range of cultures and environments included in the MGRS. These analyses support the appropriateness of pooling data from all sites and for both sexes for the purpose of developing an international standard for gross motor development.     

Assessment of differences in linear growth among populations in the WHO Multicentre Growth Reference Study

Aim: To assess differences in length/height among populations in the WHO Multicentre Growth Reference Study (MGRS) and to evaluate the appropriateness of pooling data for the purpose of constructing a single international growth standard. Methods: The MGRS collected growth data and related information from 8440 affluent children from widely differing ethnic backgrounds and cultural settings (Brazil, Ghana, India, Norway, Oman and the USA). Eligibility criteria included breastfeeding, no maternal smoking and environments supportive of unconstrained growth. The study combined longitudinal (birth to 24 mo) and cross-sectional (18–71 mo) components. For the longitudinal component, mother–infant pairs were enrolled at delivery and visited 21 times over the next 2 y. Rigorous methods of data collection and standardized procedures were applied across study sites. We evaluate the total variability of length attributable to sites and individuals, differences in length/height among sites, and the impact of excluding single sites on the percentiles of the remaining pooled sample. Results: Proportions of total variability attributable to sites and individuals within sites were 3% and 70%, respectively. Differences in length and height ranged from −0.33 to +0.49 and −0.41 to +0.46 standard deviation units (SDs), respectively, most values being below 0.2 SDs. Differences in length on exclusion of single sites ranged from −0.10 to +0.07, −0.07 to +0.13, and −0.25 to +0.09 SDs, for the 50th, 3rd and 97th percentiles, respectively. Corresponding values for height ranged from −0.09 to +0.08, −0.12 to +0.13, and −0.15 to +0.07 SDs.
Conclusion: The striking similarity in linear growth among children in the six sites justifies pooling the data and constructing a single international standard from birth to 5 y of age.     

WHO Child Growth Standards based on length/height, weight and age

Aim: To describe the methods used to construct the WHO Child Growth Standards based on length/height, weight and age, and to present resulting growth charts. Methods: The WHO Child Growth Standards were derived from an international sample of healthy breastfed infants and young children raised in environments that do not constrain growth. Rigorous methods of data collection and standardized procedures across study sites yielded very high-quality data. The generation of the standards followed methodical, state-of-the-art statistical methodologies. The Box-Cox power exponential (BCPE) method, with curve smoothing by cubic splines, was used to construct the curves. The BCPE accommodates various kinds of distributions, from normal to skewed or kurtotic, as necessary. A set of diagnostic tools was used to detect possible biases in estimated percentiles or z-score curves. Results: There was wide variability in the degrees of freedom required for the cubic splines to achieve the best model. Except for length/height-for-age, which followed a normal distribution, all other standards needed to model skewness but not kurtosis. Length-for-age and height-for-age standards were constructed by fitting a unique model that reflected the 0.7-cm average difference between these two measurements. The concordance between smoothed percentile curves and empirical percentiles was excellent and free of bias. Percentiles and z-score curves for boys and girls aged 0–60 mo were generated for weight-for-age, length/height-for-age, weight-for-length/height (45 to 110 cm and 65 to 120 cm, respectively) and body mass index-for-age.
Conclusion: The WHO Child Growth Standards depict normal growth under optimal environmental conditions and can be used to assess children everywhere, regardless of ethnicity, socio-economic status and type of feeding.     

Reliability of motor development data in the WHO Multicentre Growth Reference Study

Aim: To describe the methods used to standardize the assessment of motor milestones in the WHO Multicentre Growth Reference Study (MGRS) and to present estimates of the reliability of the assessments.
Methods: As part of the MGRS, longitudinal data were collected on the acquisition of six motor milestones by children aged 4 to 24 mo in Ghana, India, Norway, Oman and the USA. To ensure standardized data collection, the sites conducted regular standardization sessions during which fieldworkers took turns to examine and score about 10 children for the six milestones. Assessments of the children were videotaped, and later the other fieldworkers in the same site watched the videotaped sessions and independently rated performances. The assessments were also viewed and rated by the study coordinator. The coordinator's ratings were considered the reference (true) scores. In addition, one cross-site standardization exercise took place using videotapes of 288 motor assessments. The degree of concordance between fieldworkers and the coordinator was analysed using the Kappa coefficient and the percentage of agreement.
Results: Overall, high percentages of agreement (81–100%) between fieldworkers and the coordinator and "substantial" (0.61–0.80) to "almost perfect" (>0.80) Kappa coefficients were obtained for all fieldworkers, milestones and sites. Homogeneity tests confirm that the Kappas are homogeneous across sites, across milestones, and across fieldworkers. Concordance was slightly higher in the cross-site session than in the site standardization sessions. There were no systematic differences in assessing children by direct examination or through videotapes.
Conclusion: These results show that the criteria used to define performance of the milestones were similar and applied with equally high levels of reliability among fieldworkers within a site, among milestones within a site, and among sites across milestones.     

Breastfeeding in the WHO Multicentre Growth Reference Study

Aim: To document how children in the WHO Multicentre Growth Reference Study (MGRS) complied with feeding criteria and describe the breastfeeding practices of the compliant group.
Methods: The MGRS longitudinal component followed 1743 mother–infant pairs from birth to 24 mo in six countries (Brazil, Ghana, India, Norway, Oman and the USA). The study included three criteria for compliance with recommended feeding practices that were monitored at each follow-up visit through food frequency reports and 24-h dietary recalls. Trained lactation counsellors visited participating mothers frequently in the first months after delivery to help with breastfeeding initiation and prevent and resolve lactation problems.
Results: Of the 1743 enrolled newborns, 903 (51.8%) completed the follow-up and complied with the three feeding criteria. Three quarters (74.7%) of the infants were exclusively/predominantly breastfed for at least 4 mo, 99.5% were started on complementary foods by 6 mo of age, and 68.3% were partially breastfed until at least age 12 mo. Compliance varied across sites (lowest in Brazil and highest in Ghana) based on their initial baseline breastfeeding levels and sociocultural characteristics. Median breastfeeding frequency among compliant infants was 10, 9, 7 and 5 feeds per day at 3, 6, 9 and 12 mo, respectively. Compliant mothers were less likely to be employed, more likely to have had a vaginal delivery, and fewer of them were primiparous. Pacifier use was more prevalent in the non-compliant group.
Conclusion: The MGRS lactation support teams were successful in enhancing breastfeeding practices and achieving high rates of compliance with the feeding criteria required for the construction of the new growth standards.     

儿童运动协调能力与生长发育水平的关联性研究

目的 初步探讨儿童运动协调能力与生长发育水平的关联性,为明确两者的因果关系,有效促进儿童的生长发育水平提供线索.方法 在上海市虹口、普陀、浦东3个区整群抽取10所幼儿园进行调查,共1099名儿童纳入分析,采用发育性协调障碍问卷(DCDQ)对儿童的运动协调能力进行评测.采用结构方程模型对运动协调能力与儿童生长发育水平之间的关联性进行分析,采用多组结构方程模型对不同性别、年龄和是否超重儿童的关联模型差别进行分析.结果 1099名研究对象中,男童561人(51％),女童538人(49％),3岁～组354人(32.2％),4岁～组441人(40.1％),5岁～组276人(25.2％),6～7岁组28人(2.5％).结构方程模型分析结果显示在儿童运动协调的功能表现中,精细运动、粗大运动和一般协调性均与生长发育水平呈正相关,具有统计学意义(标准化系数分别为0.36,0.40,0.37,P均＜0.001);多组结构方程模型分析结果显示不同性别和年龄的结构方程模型未发现明显差异(P均＞0.05),但超重和正常组的结构模型存在差异,其中仅粗大运动与儿童生长发育水平的结构系数存在组间差异(t值=1.697,P＜0.05).结论 儿童运动协调能力与生长发育水平存在一定关联性,并且超重和正常组儿童的粗大运动与生长发育水平的关联程度存在差异,为深入开展儿童生长发育水平影响因素的研究奠定了基础.     

Child development at 5 years of age predicted mathematics ability and schooling outcomes in Malawian adolescents

Aim: This study aimed to examine the association between child development at 5 years of age and mathematics ability and schooling outcomes at 12 years of age in Malawian children. Methods: A prospective cohort study looking at 609 rural Malawian children. Outcome measures were percentage of correctly answered mathematics questions, highest school grade completed and number of times repeating school grades at 12 years of age. A child development summary score obtained at 5 years of age was the main exposure variable. Regression analyses were used to estimate the association and adjust for confounders. Sensitivity analysis was performed by handling losses to follow‐up with multiple imputation (MI) method. Results: The summary score was positively associated with percentage of correctly answered mathematics questions (p = 0.057; p = 0.031 MI) and with highest school grade completed (p = 0.096; p = 0.070 MI), and negatively associated with number of times repeating school grades (p = 0.834; p = 0.339 MI). Fine motor score at 5 years was independently associated with the mathematic score (p = 0.032; p = 0.011 MI). The association between child development and mathematics ability did not depend on school attendance. Conclusion: Child development at 5 years of age showed signs of positive association with mathematics ability and possibly with highest school grade completed at 12 years of age.     

Role of micronutrients for physical growth and mental development

Due to control of florid and severe cases of protein-energy malnutrition, deficiencies of micronutrients in children have assumed public health importance. According to National Nutrition Monitoring Bureau of India, over 50% of apparently healthy looking children have subclinical or biochemical deficiencies of vitamin A, vitamins B₂, B₆, folate and vitamin C. Over two-third of children have clinical evidences of iron deficiency while deficiency of trace minerals like iodine and zinc is quite common in certain populations. Children have food preferences and they are quite fussy to take green leafy vegetables and fruits thus compromising their intake of micronutrients from dietary sources. The full genetic potential of the child for physical growth and mental development may be compromised due to subclinical deficiencies of micronutrients which are commonly referred to as “hidden hunger”. Micronutrients are required for the integrity and optimal functioning of immune system. Children with subclinical deficiency of micronutrients are more vulnerable to develop frequent and more severe common day-to-day infections thus triggering a vicious cycle of undernutrition and recurrent infections. A number of micronutrients are required for optimal physical growth and neuromotor development. Isolated deficiencies of micronutrients are rare in clinical practice and usually deficiencies of multiple micronutrients co-exist. The first 3 years of life are most crucial and vulnerable to the hazards of undernutrition. All efforts should be made so that preschool children are given a balanced and nutritious home-based diet. However, it has been shown that it is not possible to meet 100% requirements of recommended dietary allowances (RDA’s) of micronutrients from dietary sources alone and most preschool children need administration of nutritional supplements to optimize their genetic potential for physical growth and mental development.     

Relationship between fundamental motor skills and physical fitness in children with global developmental delay

Importance::Understanding the significance of motor skills in promoting physical fitness (PF) can offer valuable insights for devising comprehensive intervention and clinical rehabilitation programs for children with global developmental delay (GDD). However, it remains unclear whether fundamental motor skills (FMS) can improve the PF of children with GDD.Objective::To investigate the correlation between FMS and PF in children with GDD.Methods::A total of 180 children with GDD and 180 typically developing (TD) children aged 3-5 years were selected. All participants completed the Gesell Developmental Schedule, FMS, and PF tests at Beijing Children’s Hospital between September 2022 and August 2023. Partial correlation and regression analyses were performed to examine the relationship between FMS and PF.Results::Children with GDD had significantly lower FMS and PF scores compared to TD children ( P < 0.05). No significant differences were found between males and females with GDD in FMS and PF score ( P > 0.05). A more severe developmental delay was associated with lower FMS and PF scores. The correlation coefficients between individual FMS items and individual PF items, as well as the total PF score, ranged from 0.20 to 0.56. Regression analysis indicated that manual dexterity ( β = 0.241, P = 0.029) and body balance ( β = 0.399, P = 0.001) significantly predicted the total PF score. Interpretation::In children with GDD, both FMS and PF are underdeveloped. Focusing on motor skills development is vital for promoting their PF.     

Enrolment and baseline characteristics in the WHO Multicentre Growth Reference Study

Aim: To describe the WHO Multicentre Growth Reference Study (MGRS) sample with regard to screening, recruitment, compliance, sample retention and baseline characteristics.
Methods: A multi-country community-based study combining a longitudinal follow-up from birth to 24 mo with a cross-sectional survey of children aged 18 to 71 mo. Study subpopulations had to have socio-economic conditions favourable to growth, low mobility and ≥ 20% of mothers practising breastfeeding. Individual inclusion criteria were no known environmental constraints on growth, adherence to MGRS feeding recommendations, no maternal smoking, single term birth and no significant morbidity. For the longitudinal sample, mothers and newborns were screened and enrolled at birth and visited 21 times at home until age 24 mo.
Results: About 83% of 13 741 subjects screened for the longitudinal component were ineligible and 5% refused to participate. Low socio-economic status was the predominant reason for ineligibility in Brazil, Ghana, India and Oman, while parental refusal was the main reason for non-participation in Norway and USA. Overall, 88.5% of enrolled subjects completed the 24-mo follow-up, and 51% (888) complied with the MGRS feeding and no-smoking criteria. For the cross-sectional component, 69% of 21 510 subjects screened were excluded for similar reasons as for the longitudinal component. Although low birthweight was not an exclusion criterion, its prevalence was low (2.1% and 3.2% in the longitudinal and cross-sectional samples, respectively). Parental education was high, between 14 and 15 y of education on average.
Conclusion: The MGRS criteria were effective in selecting healthy children with comparable affluent backgrounds across sites and similar characteristics between longitudinal and cross-sectional samples within sites.     

An Approach to the Estimation of Growth Standards: The Univariate Case

ABSTRACT. This paper shows how reference values can be determined when the underlying characteristic (say, weight) follows a distribution that is not too distant from the Gaussian. Application of the normalizing Box-Cox power transformation is the basis of our approach. This transformation is monotonic and hence invertible, so offering the choice of two scales of measurement on which to work—the original and the Gaussian. Modified versions of the procedure are provided allowing use of the basic transformation in the presence of certain deficiencies in the data, principally measurement error and misclassification. It is shown that application of Box-Cox to a cohort at several points in time can be quite revealing. When the data are already symmetrical the Box-Cox transformation has no effect: in this case the John-Draper modulus transformation and modifications of it are shown to be helpful. All of this is illustrated by using data from the Swedish Longitudinal Growth Study.     

Association between sleep position and early motor development

OBJECTIVE: To compare motor performance in infants sleeping in prone versus supine positions. STUDY DESIGN: Healthy 4-month-olds (supine: n = 71, prone: n = 12) and 6-month olds (supine: n = 50, prone: n = 22) were evaluated with the Alberta Infant Motor Scale (AIMS) and Peabody Developmental Motor Scale (PDMS), and parents completed a positioning diary. Infants were reassessed at 15 months. RESULTS: At 4 months, motor scores were lower in the supine group and were less likely to achieve prone extension (P < .05). At 6 months, there were wide discrepancies on the AIMS (supine: 44.5 +/- 21.6, prone: 60.0 +/- 18.8, P = .005) and the gross motor PDMS (supine: 85.7 +/- 7.6, prone: 90.2 +/- 9.5, P = .03). Motor delays were documented in 22% of babies sleeping supine. Prone sleep-positioned infants were more likely to sit and roll. Daily exposure to awake prone positioning was predictive of motor performance in infants sleeping supine. At 15 months, sleep position continued to predict motor performance. CONCLUSIONS: Infants sleeping supine may exhibit early motor lags, associated with less time in prone while awake. This has implications for accurate interpretation of assessment of infants at risk and prevention of inappropriate referrals. Rate of infant motor development appears influenced by extrinsic factors such as positioning practices.     

Cerebral palsy in Victoria: motor types, topography and gross motor function

Objectives:   To study the relationships between motor type, topographical distribution and gross motor function in a large, population-based cohort of children with cerebral palsy (CP), from the State of Victoria, and compare this cohort to similar cohorts from other countries.
Methods:   An inception cohort was generated from the Victorian Cerebral Palsy Register (VCPR) for the birth years 1990–1992. Demographic information, motor types and topographical distribution were obtained from the register and supplemented by grading gross motor function according to the Gross Motor Function Classification System (GMFCS).
Results:   Complete data were obtained on 323 (86%) of 374 children in the cohort. Gross motor function varied from GMFCS level I (35%) to GMFCS level V (18%) and was similar in distribution to a contemporaneous Swedish cohort. There was a fairly even distribution across the topographical distributions of hemiplegia (35%), diplegia (28%) and quadriplegia (37%) with a large majority of young people having the spastic motor type (86%).
Conclusions:   The VCPR is ideal for population-based studies of gross motor function in children with CP. Gross motor function is similar in populations of children with CP in developed countries but the comparison of motor types and topographical distribution is difficult because of lack of consensus with classification systems. Use of the GMFCS provides a valid and reproducible method for clinicians to describe gross motor function in children with CP using a universal language.     

Relationships between physical growth, mental development and nutritional supplementation in stunted children: the Jamaican study

The relationship between physical growth and change in mental development on the Griffiths mental development scales was investigated in 127 stunted Jamaican children over a 2-year period. The role of nutritional supplementation in this relationship was examined. There were no consistent associations between changes in weight-for-height or head circumference and developmental change. Height gain over 2 years was significantly associated with change in mental age, and locomotor and hearing and speech subscale scores. Height gain in the first year predicted change in mental age, and hearing and speech in the second year. Some of the effect of supplementation on development was shared with linear growth. Therefore, nutrition probably explains part of the relationship between growth and development. However, supplementation also had effects on development independent of growth. The benefits of supplementation on development and the extent to which they were shared with growth varied among the subscales.     

不同类型小于胎龄儿的生长发育比较

各国报道的小于胎龄儿发生率约为3％。小于胎龄儿是导致围生期患儿发病和死亡的重要原因之一,且预后与成年期多种疾病相关。仅通过出生体重来判断小于胎龄儿的生长受限不够全面,因为未考虑到小于胎龄儿的身体比例。根据孕期影响因子的来源、作用于胎儿的时间和作用严重程度的不同,会产生两类小于胎龄儿：匀称型小于胎龄儿和非匀称型小于胎龄儿。二者出生后的体格和神经发育情况可能存在差异。该文通过比较各分类指标,并在各分类指标下探讨匀称型小于胎龄儿和非匀称型小于胎龄儿的体格神经发育差异。     

过敏性紫癜患儿尿清蛋白与血管内皮生长因子的相关性

目的探讨过敏性紫癜(HSP)、过敏性紫癜性肾炎(HSPN)患儿尿清蛋白与血管内皮生长因子(VEGF)的相关性。方法选择2004-2006年本院儿科、皮肤科就诊的29例HSP患儿为研究对象,并选取同期本院体检健康的21例儿童作为对照,采用磺柳酸比浊法测定各组尿清蛋白排泄率(UAER),并根据UAER将HSP患儿分为紫癜无肾损害组(HSP组)及HSPN组。酶联免疫吸附试验测定各组血清VEGF水平,并采用SPSS10.0软件比较UAER和VEGF在HSP与HSPN的水平变化以及HSPN治疗前后的水平变化。结果HSP组24h尿清蛋白[(0.05±0.02)g/d]与健康对照组[(0.04±0.02)g/d]比较无显著性差异(P>0.05),HSPN组24h尿清蛋白[(3.01±1.52)g/d]与健康对照组、HSP组比较均有显著性差异(Pa<0.01);HSP组血清VEGF水平[(98.2±48.3)ng/L]与健康对照组[(69.5±19.1)ng/L]比较有显著性差异(P<0.05),HSPN组血清VEGF水平[(179.2±69.3)ng/L]与健康对照组、HSP组比较均有非常显著性差异(Pa<0.01);治疗后24h尿清蛋白[(0.53±0.31)g/d]和VEGF[(81.4±59.6)ng/L]均降低,较治疗前有非常显著性差异(Pa<0.01);24h尿清蛋白与血清VEGF水平呈正相关(r=0.519P<0.05)。结论VEGF参与HSP、HSPN的发病,并与尿清蛋白的发生、发展有关。     

早产小于胎龄儿和适于胎龄儿生长发育状况随访分析

目的观察早产小于胎龄儿(SGA)和适于胎龄儿(AGA)出院后体格生长及智能发育状况。方法选择2009年2月至2012年12月出院的早产儿220例,根据出生时状况分为SGA组和AGA组,在矫正月龄7个月内定期测量身长、体质量、身长,头围,并由专职人员进行发育商测试,比较两组间差异。结果纠正1~6月龄SGA组体质量Z值均小于AGA组,差异有统计学意义(P0.05);纠正7月龄差异无统计学意义(P0.05);纠正1~5月龄SGA组身长Z值均小于AGA组,差异有统计学意义(P0.05),纠正6月龄之后差异消失;纠正1~7月龄SGA组头围Z值均小于AGA组,差异有统计学意义(P0.05)。SGA组及AGA组在纠正5~7月龄发育商分别为96.7±9.2及102.9±9.9,差异有统计学意义(P0.05);SGA组大运动、认知及语言能区得分均低于AGA组,差异有统计学意义(P0.05)。结论 SGA早产儿在纠正7月龄内体质量追赶性生长较好,但身长追赶性生长则相对较差,头围追赶最差;SGA早产儿纠正5~7月龄智能发育水平总体落后于AGA早产儿,尤以大运动、认知和语言能区落后较明显。     

Hypertension during pregnancy, with and without specific hypotensive treatment. II. The growth and development of the infant in the first year of life

The growth and development of three groups of infants were prospectively assessed from birth to 12 mth. In two groups the mothers had been hypertensive before the 28th wk of gestation; one group was randomly allocated to specific hypotensive therapy, the other group was allocated to no specific treatment. The third group was a sample of the hospital population. General health, and the incidence of sight and hearing problems did not differ. Infants in the treated hypertensive group had had more perinatal problems, and there was an excess of infants with relatively small heads for their gestational age at birth. At 6 mth their heads were still smaller than the hospital sample, but by the age of 1 yr the difference was no longer present. The neurological status of infants in the untreated hypertensive group was less favourable in the neonatal period, and there was still an excess of infants in this group rated questionable on neurological assessment at the age of 12 mth. In both hypertensive groups there was an excess of infants with delayed fine-motor function at 6 mth, and in the untreated group there was an excess with delayed gross-motor function at 12 mth compared with the hospital sample. Our varied findings draw attention to the dangers of assessing the effects of different pregnancy conditions in terms of neonatal mortality and morbidity alone. Our date indicate that follow-up should extend for longer than 12 mth when the effects of adverse pregnancy factors and their management are under consideration. Further evaluation will be made when these children are 4 yr old.