Biomedical subjects

Adelheid W Onyango

Publications and source records attributed to Adelheid W Onyango.

10 recordsLinked to original sources

PubMed2007

Comparison of the WHO child growth standards and the CDC 2000 growth charts.

The evaluation of child growth trajectories and the interventions designed to improve child health are highly dependent on the growth charts used. The U.S. CDC and the WHO, in May 2000 and April 2006, respectively, released new growth charts to replace the 1977 NCHS reference. The WHO charts are based for the first time on a prescriptive, prospective, international sample of infants selected to represent optimum growth. This article compares the WHO and CDC curves and evaluates the growth performance of healthy breast-fed infants according to both. As expected, there are important differences between the WHO and CDC charts that vary by age group, growth indicator, and specific Z-score curve. Differences are particularly important during infancy, which is likely due to differences in study design and characteristics of the sample, such as type of feeding. Overall, the CDC charts reflect a heavier, and somewhat shorter, sample than the WHO sample. This results in lower rates of undernutrition (except during the first 6 mo of life) and higher rates of overweight and obesity when based on the WHO standards. Healthy breast-fed infants track along the WHO standard's weight-for-age mean Z-score while appearing to falter on the CDC chart from 2 mo onwards. Shorter measurement intervals in the WHO standards result in a better tool for monitoring the rapid and changing rate of growth in early infancy. Their adoption would have important implications for the assessment of lactation performance and the adequacy of infant feeding and would bring coherence between the tools used to assess growth and U.S. national guidelines that recommend breast-feeding as the optimal source of nutrition during infancy.

Body Height↗

PubMed2007

Field-testing the WHO child growth standards in four countries.

In April 2006 the WHO released a set of growth standards for children from birth to the age of 5 y. Prior to their release, the standards were field-tested in 4 countries. The main objective was to compare children's length/height-for-age and weight-for-length/height based on the new standards with clinician assessments of the same children. The study sampled children <5-y-old attending well-child clinics in 2 affluent populations (Argentina and Italy) and 2 less-affluent ones (Maldives and Pakistan). Length/height and weight were measured by doctors and epidemiologists who also recorded a clinical assessment of each child's length/height in relation to age and weight relative to length/height. Anthropometric indicators of nutritional status were generated based on the WHO standards. As expected, Pakistan and the Maldives had higher rates of stunting, wasting, and underweight than Italy and Argentina, and the reverse was true for overweight and obesity. Where stunting was prevalent, the children classified as short were a mean <-2 SD for height-for-age. In all sites, the children classified as thin were indeed wasted (<-2 SD for weight-for-height) and a positive association in trend was evident between weight-for-height and the line-up of groups from thin to obese. The overall concordance between clinical assessments and the WHO standards-based indicators attested to the clinical soundness of the standards.

Argentina↗

PubMed2006

Comparison of the World Health Organization (WHO) Child Growth Standards and the National Center for Health Statistics/WHO international growth reference: implications for child health programmes.

OBJECTIVES: To compare growth patterns and estimates of malnutrition based on the World Health Organization (WHO) Child Growth Standards ('the WHO standards') and the National Center for Health Statistics (NCHS)/WHO international growth reference ('the NCHS reference'), and discuss implications for child health programmes. DESIGN: Secondary analysis of longitudinal data to compare growth patterns (birth to 12 months) and data from two cross-sectional surveys to compare estimates of malnutrition among under-fives. SETTINGS: Bangladesh, Dominican Republic and a pooled sample of infants from North America and Northern Europe. SUBJECTS: Respectively 4787, 10 381 and 226 infants and children. RESULTS: Healthy breast-fed infants tracked along the WHO standard's weight-for-age mean Z-score while appearing to falter on the NCHS reference from 2 months onwards. Underweight rates increased during the first six months and thereafter decreased when based on the WHO standards. For all age groups stunting rates were higher according to the WHO standards. Wasting and severe wasting were substantially higher during the first half of infancy. Thereafter, the prevalence of severe wasting continued to be 1.5 to 2.5 times that of the NCHS reference. The increase in overweight rates based on the WHO standards varied by age group, with an overall relative increase of 34%. CONCLUSIONS: The WHO standards provide a better tool to monitor the rapid and changing rate of growth in early infancy. Their adoption will have important implications for child health with respect to the assessment of lactation performance and the adequacy of infant feeding. Population estimates of malnutrition will vary by age, growth indicator and the nutritional status of index populations.

Breast Feeding↗

PubMed2004

Worldwide practices in child growth monitoring.

OBJECTIVE: To describe child growth monitoring practices worldwide in preparation for the construction and application of a new international growth reference. STUDY DESIGN: A questionnaire was sent to Ministries of Health in 202 countries requesting information on growth charts used in national programs, reference populations, classification systems, problems encountered, and actions taken against growth faltering. Countries also provided hard copies of charts in current use. This information was entered and analyzed in Microsoft Access. RESULTS: Responses were received from 178 (88%) countries, 154 of which included growth charts (n=806). Two thirds of the charts covered preschool age. All countries used weight-for-age, over half relying on this index alone. The reference most commonly used (68%) was the National Center for Health Statistics/World Health Organization population, with regional variations, where most European countries used local standards. Sixty-three percent of charts classified child growth on percentiles, whereas about one fifth used z scores. Problems reported were both conceptual (eg, interpreting growth trajectories) and practical (eg, lack of equipment). CONCLUSIONS: The survey demonstrates that growth charts are used universally in pediatric care. The information gathered on current use and interpretation of growth charts provides important guidance for constructing and applying the new reference.

Anthropometry↗

PubMed2004

The WHO Multicentre Growth Reference Study: planning, study design, and methodology.

The World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) is a community-based, multicountry project to develop new growth references for infants and young children. The design combines a longitudinal study from birth to 24 months with a cross-sectional study of children aged 18 to 71 months. The pooled sample from the six participating countries (Brazil, Ghana, India, Norway, Oman, and the United States) consists of about 8,500 children. The study subpopulations had socioeconomic conditions favorable to growth, and low mobility, with at least 20% of mothers following feeding recommendations and having access to breastfeeding support. The individual inclusion criteria were absence of health or environmental constraints on growth, adherence to MGRS feeding recommendations, absence of maternal smoking, single term birth, and absence of significant morbidity. In the longitudinal study, mothers and newborns were screened and enrolled at birth and visited at home 21 times: at weeks 1, 2, 4, and 6; monthly from 2 to 12 months; and every 2 months in their second year. In addition to the data collected on anthropometry and motor development, information was gathered on socioeconomic, demographic, and environmental characteristics, perinatal factors, morbidity, and feeding practices. The prescriptive approach taken is expected to provide a single international reference that represents the best description of physiological growth for all children under five years of age and to establish the breastfed infant as the normative model for growth and development.

Anthropometry↗

PubMed2004

Measurement and standardization protocols for anthropometry used in the construction of a new international growth reference.

Thorough training, continuous standardization, and close monitoring of the adherence to measurement procedures during data collection are essential for minimizing random error and bias in multicenter studies. Rigorous anthropometry and data collection protocols were used in the WHO Multicentre Growth Reference Study to ensure high data quality. After the initial training and standardization, study teams participated in standardization sessions every two months for a continuous assessment of the precision and accuracy of their measurements. Once a year the teams were restandardized against the WHO lead anthropometrist, who observed their measurement techniques and retrained any deviating observers. Robust and precise equipment was selected and adapted for field use. The anthropometrists worked in pairs, taking measurements independently, and repeating measurements that exceeded preset maximum allowable differences. Ongoing central and local monitoring identified anthropometrists deviating from standard procedures, and immediate corrective action was taken. The procedures described in this paper are a model for research settings.

Anthropometry↗

PubMed2004

Assessment of gross motor development in the WHO Multicentre Growth Reference Study.

The objective of the Motor Development Study was to describe the acquisition of selected gross motor milestones among affluent children growing up in different cultural settings. This study was conducted in Ghana, India, Norway, Oman, and the United States as part of the longitudinal component of the World Health Organization (WHO) Multicentre Growth Reference Study (MGRS). Infants were followed from the age of four months until they could walk independently. Six milestones that are fundamental to acquiring self-sufficient erect locomotion and are simple to evaluate were assessed: sitting without support, hands-and-knees crawling, standing with assistance, walking with assistance, standing alone, and walking alone. The information was collected by both the children's caregivers and trained MGRS fieldworkers. The caregivers assessed and recorded the dates when the milestones were achieved for the first time according to established criteria. Using standardized procedures, the fieldworkers independently assessed the motor performance of the children and checked parental recording at home visits. To ensure standardized data collection, the sites conducted regular standardization sessions. Data collection and data quality control took place simultaneously. Data verification and cleaning were performed until all queries had been satisfactorily resolved.

Brazil↗

PubMed2004

Managing data for a multicountry longitudinal study: experience from the WHO Multicentre Growth Reference Study.

The World Health Organization (WHO) Multicentre Growth Reference (MGRS) data management protocol was designed to create and manage a large data bank of information collected from multiple sites over a period of several years. Data collection and processing instruments were prepared centrally and used in a standardized fashion across sites. The data management system contained internal validation features for timely detection of data errors, and its standard operating procedures stipulated a method of master file updating and correction that maintained a clear trail for data auditing purposes. Each site was responsible for collecting, entering, verifying, and validating data, and for creating site-level master files. Data from the sites were sent to the MGRS Coordinating Centre every month for master file consolidation and more extensive quality control checking. All errors identified at the Coordinating Centre were communicated to the site for correction at source. The protocol imposed transparency on the sites' data management activities but also ensured access to technical help with operation and maintenance of the system. Through the rigorous implementation of what has been a highly demanding protocol, the MGRS has accumulated a large body of very high-quality data.

Child Development↗

PubMed2003

Dietary diversity, child nutrition and health in contemporary African communities.

Many infants in sub-Saharan Africa (SSA) begin to receive cereal-based supplemental feeds well before the age (6 months) recommended for the introduction of 'safe and nutritionally adequate' complementary foods, or in rarer instances, do not receive these until the second year. The diets offered are monotonous and bulky, and rarely cover the shortfall left by breast milk in providing the energy and nutrients required to support rapid growth, build nutrient stores and assure resistance to infection. The pattern of growth and prevalence of malnutrition observed from birth through the first 5 years in SSA are suggestive of the nutrient inadequacies of the diet and the experience of infection. However, it is difficult to link poor growth and specific nutrient deficiencies in epidemiological studies because multiple nutrients are required for growth and deficiencies usually involve several nutrients. Moreover, accurate measurement of nutrient intakes is no small challenge. In this regard, qualitative and easier-to-measure characteristics of diet which are associated with nutrient adequacy could serve as alternative determinant factors in studies looking at causes of malnutrition. Dietary diversity is proposed as a candidate indicator of food security and predictor of nutritional status, but there is need for further research to standardize definitions and methodology before it can be applied widely.

Africa South of the Sahara↗

PubMed2002

The contribution of breast milk to toddler diets in western Kenya.

OBJECTIVE: To understand the relative contributions of breast milk and the weaning diet to overall nutrient intake, with a view to designing and implementing appropriate programmes to improve complementary feeding in developing countries. METHODS: Complementary food intake was measured in a sample of 250 toddlers (mean baseline age: 13.9 +/- 2.4 months) using 24-h dietary recall interviews administered once every 3 weeks over a 6-month period. Breast-milk intake over a 24-h period was measured using the test-weighing method in a subsample of 50 children. Regression effects of age and sex on observed milk intakes were estimated and imputed to the whole sample to estimate mean intake over the observation period. Total energy and nutrient intakes were evaluated for adequacy with reference to published estimates of toddler requirements. FINDINGS: Total energy intake (1029 kcal/day) was adequate, with breast milk supplying an average of 328 kcal/day (32%), but vitamin A, riboflavin, calcium, iron and zinc intakes were below current estimates of required intakes. Observed limitations in nutrient intake were consistent with the finding that almost half of the toddlers were stunted. The prevalence of wasting was 6% at baseline and 4% at final assessment. Although food consumption increased when breastfeeding stopped, it could not fully compensate for the fat and vitamin A previously supplied by breast milk. CONCLUSIONS: The nutritional role of mother's milk in the second year is inversely related to the adequacy of the complementary diet. In this study, breast milk was an irreplaceable source of fat and vitamin A. When the weaning diet is inadequate for key nutrients because of low intake or poor bioavailability, breast milk assumes greater nutritional significance in the second year of life but does not guarantee adequate nutrient intakes.

Child Nutritional Physiological Phenomena↗