Algorithms for converting estimates of child malnutrition based on the NCHS reference into estimates based on the WHO Child Growth Standards

<p>Abstract</p> <p>Background</p> <p>The child growth standards released by the World Health Organization (WHO) in 2006 have several technical advantages over the previous 1977 National Center for Health Statistics (NCHS)/WHO reference and are recommended for international comparisons and secular trend analysis of child malnutrition. To obtain comparable data over time, earlier surveys should be reanalyzed using the WHO standards; however, reanalysis is impossible for older surveys since the raw data are not available. This paper provides algorithms for converting estimates of child malnutrition based on the NCHS reference into estimates based on the WHO standards.</p> <p>Methods</p> <p>Sixty-eight surveys from the WHO Global Database on Child Growth and Malnutrition were analyzed using the WHO standards to derive estimates of underweight, stunting, wasting and overweight. The prevalences based on the NCHS reference were taken directly from the database. National/regional estimates with a minimum sample size of 400 children were used to develop the algorithms. For each indicator, a simple linear regression model was fitted, using the logit of WHO and NCHS estimates as, respectively, dependent and independent variables. The resulting algorithms were validated using a different set of surveys, on the basis of which the point estimate and 95% confidence interval (CI) of the predicted WHO prevalence were compared to the observed prevalence.</p> <p>Results</p> <p>In total, 271 data points were used to develop the algorithms. The correlation coefficients (R²) were all greater than 0.90, indicating that most of the variability of the dependent variable is explained by the fitted model. The average difference between the predicted WHO estimate and the observed value was <0.5% for stunting, wasting and overweight. For underweight, the mean difference was 0.8%. The proportion of the 95% CI of the predicted estimate containing the observed prevalence was above 90% for all four indicators. The algorithms performed equally well for surveys without the entire age coverage 0 to 60 months.</p> <p>Conclusion</p> <p>To obtain comparable data concerning child malnutrition, individual survey data should be analyzed using the WHO standards. When the raw data are not available, the algorithms presented here provide a highly accurate tool for converting existing NCHS estimates into WHO estimates.</p

Timing of Menarche in Girls Adopted from China: a Cohort Study

Background: Girls adopted internationally from some states have been found to have high rates of early puberty, including early menarche. Explanations for the link between international adoption and early puberty include post-adoption catch-up growth triggering puberty, and under-recorded age. Methods: We compared menarcheal age in a cohort of 814 girls adopted from China into North America against menarcheal ages in girls in China. Adoptive parents provided survey data on their daughters’ weight in 2005 and on menarcheal status and age at menarche in 2011. Results: Estimated median age at menarche for adopted Chinese girls is 12.37y (95% CI: 11.84-13.00y). Estimated prevalence of menarcheal age ≤10.00y for adopted girls is 3%. These findings are similar to published findings on non-adopted Chinese girls. The distribution of menarche of adopted girls and non-adopted girls at the estimated incidence rates P3-P97 are also similar. Among the 609 girls whose parents reported on their weight shortly after adoption, 148 (24.3%) were –2SD or more below the median weight in the WHO weight-for-age tables. The proportion of these girls who had attained menarche was not statistically different from other girls. Conclusions: For girls adopted from China, the age of menarche, the percentage of girls attaining menarche <10y and the distribution of menarcheal age are all similar to Chinese girls growing up in China

Fetal, neonatal, infant, and child international growth standards: an unprecedented opportunity for an integrated approach to assess growth and development.

The recent publication of fetal growth and gestational age-specific growth standards by the International Fetal and Newborn Growth Consortium for the 21st Century Project and the previous publication by the WHO of infant and young child growth standards based on the WHO Multicentre Growth Reference Study enable evaluations of growth from ∼9 wk gestation to 5 y. The most important features of these projects are the prescriptive approach used for subject selection and the rigorous testing of the assertion that growth is very similar among geographically and ethnically diverse nonisolated populations when health, nutrition, and other care needs are met and the environment imposes minimal constraints on growth. Both studies documented that with adequate controls, the principal source of variability in growth during gestation and early childhood resides among individuals. Study sites contributed much less to observed variability. The agreement between anthropometric measurements common to both studies also is noteworthy. Jointly, these studies provide for the first time, to my knowledge, a conceptually consistent basis for worldwide and localized assessments and comparisons of growth performance in early life. This is an important contribution to improving the health care of children across key periods of growth and development, especially given the appropriate interest in pursuing optimal health in the first 1000 d, i.e., the period covering fertilization/implantation, gestation, and postnatal life to 2 y of age

Age- and size-related reference ranges: A case study of spirometry through childhood and adulthood

Age-related reference ranges are useful for assessing growth in children. The LMS method is a popular technique for constructing growth charts that model the age-changing distribution of the measurement in terms of the median, coefficient of variation and skewness. Here the methodology is extended to references that depend on body size as well as age, by exploiting the flexibility of the generalised additive models for location, scale and shape (GAMLSS) technique. GAMLSS offers general linear predictors for each moment parameter and a choice of error distributions, which can handle kurtosis as well as skewness. A key question with such references is the nature of the age-size adjustment, additive or multiplicative, which is explored by comparing the identity link and log link for the median predictor

A prospective study on the link between weight‐related self‐stigma and binge eating: role of food addiction and psychological distress

Objectives: This prospective study investigated the link between weight‐related self‐stigma and binge eating by (a) examining the temporal association between weight‐related self‐stigma and binge eating; (b) investigating the mediating role of food addiction in the association between weight‐related self‐stigma and binge eating; and (c) examining the mediating role of psychological distress in the association between weight‐related self‐stigma and binge eating. Method: Participants comprised 1,497 adolescents (mean = 15.1 years; SD = 6.0). Body mass index and weight bias were assessed at baseline; psychological distress (i.e., depression, anxiety, and stress) assessed and food addiction at 3 months; and binge eating at 6 months. The mediation model was analyzed using Model 4 in the PROCESS macro for SPSS with 10,000 bootstrapping resamples. Results: There was no significant direct association between weight‐related self‐stigma and binge eating. However, food addiction and psychological distress significantly mediated the association between weight‐related self‐stigma and binge eating. Discussion: These findings highlight the indirect association between weight‐related self‐stigma and binge eating via food addiction and psychological distress. Consequently, intervention programs targeting food addiction and psychological distress among adolescents may have significant positive effects on outcomes for weight‐related self‐stigma and binge eating. The findings will be beneficial to researchers and healthcare professionals working with adolescents during this critical developmental period

The test characteristics of head circumference measurements for pathology associated with head enlargement: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>The test characteristics of head circumference (HC) measurement percentile criteria for the identification of previously undetected pathology associated with head enlargement in primary care are unknown.</p> <p>Methods</p> <p>Electronic patient records were reviewed to identify children age 3 days to 3 years with new diagnoses of intracranial expansive conditions (IEC) and metabolic and genetic conditions associated with macrocephaly (MGCM). We tested the following HC percentile threshold criteria: ever above the 95^th, 97^th, or 99.6^thpercentile and ever crossing 2, 4, or 6 increasing major percentile lines. The Centers for Disease Control and World Health Organization growth curves were used, as well as the primary care network (PCN) curves previously derived from this cohort.</p> <p>Results</p> <p>Among 74,428 subjects, 85 (0.11%) had a new diagnosis of IEC (n = 56) or MGCM (n = 29), and between these 2 groups, 24 received intervention. The 99.6^thpercentile of the PCN curve was the only threshold with a PPV over 1% (PPV 1.8%); the sensitivity of this threshold was only 15%. Test characteristics for the 95th percentiles were: sensitivity (CDC: 46%; WHO: 55%; PCN: 40%), positive predictive value (PPV: CDC: 0.3%; WHO: 0.3%; PCN: 0.4%), and likelihood ratios positive (LR+: CDC: 2.8; WHO: 2.2; PCN: 3.9). Test characteristics for the 97th percentiles were: sensitivity (CDC: 40%; WHO: 48%; PCN: 34%), PPV (CDC: 0.4%; WHO: 0.3%; PCN: 0.6%), and LR+ (CDC: 3.6; WHO: 2.7; PCN: 5.6). Test characteristics for crossing 2 increasing major percentile lines were: sensitivity (CDC: 60%; WHO: 40%; PCN: 31%), PPV (CDC: 0.2%; WHO: 0.1%; PCN: 0.2%), and LR+ (CDC: 1.3; WHO: 1.1; PCN: 1.5).</p> <p>Conclusions</p> <p>Commonly used HC percentile thresholds had low sensitivity and low positive predictive value for diagnosing new pathology associated with head enlargement in children in a primary care network.</p

Use of the new World Health Organization child growth standards to describe longitudinal growth of breastfed rural Bangladeshi infants and young children.

BACKGROUND: Although the National Center for Health Statistics (NCHS) reference has been widely used, in 2006 the World Health Organization (WHO) released new standards for assessing growth of infants and children worldwide. OBJECTIVE: To assess and compare the growth of breastfed rural Bangladeshi infants and young children based on the new WHO child growth standards and the NCHS reference. METHODS: We followed 1343 children in the Maternal and Infant Nutrition Intervention in Matlab (MINIMat) study from birth to 24 months of age. Weights and lengths of the children were measured monthly during infancy and quarterly in the second year of life. Anthropometric indices were calculated using both WHO standards and the NCHS reference. The growth pattern and estimates of undernutrition based on the WHO standards and the NCHS reference were compared. RESULTS: The mean birthweight was 2697 +/- 401 g, with 30% weighing <2500 g. The growth pattern of the MINIMat children more closely tracked the WHO standards than it did the NCHS reference. The rates of stunting based on the WHO standards were higher than the rates based on the NCHS reference throughout the first 24 months. The rates of underweight and wasting based on the WHO standards were significantly different from those based on the NCHS reference. CONCLUSIONS: This comparison confirms that use of the NCHS reference misidentifies undernutrition and the timing of growth faltering in infants and young children, which was a key rationale for constructing the new WHO standards. The new WHO child growth standards provide a benchmark for assessing the growth of breastfed infants and children