Assessment of Vitamin D status and association with inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project.

BACKGROUND: It is unclear whether 25(OH)D concentrations in children and female adults may be influenced by inflammation and thus require adjustment when estimating the population prevalence of vitamin D deficiency. OBJECTIVES: We examined correlations between inflammation biomarkers, CRP or alpha-1-acid glycoprotein (AGP), and serum 25(OH)D concentrations among preschool children (PSC; 6-59 mo) and nonpregnant females of reproductive age (FRA; 15-49 y). METHODS: We analyzed cross-sectional data from 6 nationally representative nutrition surveys (Afghanistan, Cambodia, Pakistan, UK, USA, and Vietnam) conducted among PSC (n = 9880) and FRA (n = 14,749) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia project. Rank correlations between CRP or AGP and 25(OH)D concentrations were examined while taking into account complex survey design effects. RESULTS: Among both PSC and FRA, correlations between inflammation and vitamin D biomarkers were weak and inconsistent across surveys. For PSC, correlation coefficients between CRP and 25(OH)D concentrations ranged from -0.04 to 0.08, and correlations between AGP and 25(OH)D ranged from 0.01 to 0.05. Correlation coefficients between CRP and 25(OH)D for FRA ranged from -0.11 to 0.14, and correlations between AGP and 25(OH)D concentrations ranged from -0.05 to 0.01. CONCLUSIONS: Based on the weak and inconsistent correlations between CRP or AGP and 25(OH)D, there is no rationale to adjust for these inflammation biomarkers when estimating population prevalence of vitamin D deficiency in PSC or FRA.

Calcium status assessment at the population level: Candidate approaches and challenges.

Inadequate dietary calcium intake is a global public health problem that disproportionately affects low- and middle-income countries. However, the calcium status of a population is challenging to measure, and there are no standard methods to identify high-risk communities even in settings with an elevated prevalence of a disease caused or exacerbated by low calcium intake (e.g., rickets). The calcium status of a population depends on numerous factors, including intake of calcium-rich foods; the bioavailability of the types of calcium consumed in foods and supplements; and population characteristics, including age, sex, vitamin D status, and genetic attributes that influence calcium retention and absorption. The aim of this narrative review was to assess candidate indicators of population-level calcium status based on a range of biomarkers and measurement methods, including dietary assessment, calcium balance studies, hormonal factors related to calcium, and health outcomes associated with low calcium status. Several promising approaches were identified, but there was insufficient evidence of the suitability of any single indicator to assess population calcium status. Further research is required to develop and validate specific indicators of calcium status that could be derived from the analysis of data or samples that are feasibly collected in population-based surveys.

Physical Activity and the Home Environment of Pre-School-Aged Children in Urban Bangladesh.

Physical activity (PA) is a key determinant of health and development, yet few studies have examined PA levels and risk factors for low PA among young children in low- and middle-income countries. This study aimed to describe the PA and sedentary (SED) behavior levels of preschool-aged children in Dhaka, Bangladesh, and to estimate the associations between potential risk factors in the home built environment and moderate to vigorous PA (MVPA). In a sample of preschool-aged children (n = 65) in Dhaka, PA and SED behavior were measured for 7 days using ActiGraph GT3X-BT accelerometers. Characteristics of the home built environment, socioeconomic factors, and anthropometry were also measured. Linear mixed-effects models were used to estimate multivariable-adjusted associations between characteristics of the home environment and MVPA. Preschool-aged children spent a mean (±standard deviation) 421 ± 48 and 82 ± 23 min per day sedentary and in MVPA, respectively. There were no statistically significant associations between factors in the home built environment (indoor area, presence of an open stairwell, and presence of gross motor activity facilitating items) and MVPA. These findings suggest that the studied characteristics of the home built environment may not significantly influence the MVPA observed among preschool-aged children in Dhaka. Future research should focus on other structural and behavioral factors that facilitate PA among young children in dense urban settings.

A novel development indicator based on population-average height trajectories of children aged 0-5 years modelled using 145 surveys in 64 countries, 2000-2018.

INTRODUCTION: Children's growth status is an important measure commonly used as a proxy indicator of advancements in a country's health, human capital and economic development. We aimed to assess the feasibility of using Super-Imposition by Translation And Rotation (SITAR) models for summarising population-based cross-sectional height-by-age data of children under 5 years across 64 countries. METHODS: Using 145 publicly available Demographic and Health Surveys of children under 5 years across 64 low-income and middle-income countries from 2000 to 2018, we created a multicountry pseudo-longitudinal dataset of children's heights. RESULTS: SITAR models including two parameters (size and intensity) explained 81% of the between-survey variation in mean boys' height and 80% in mean girls' height. Size parameters for boys and girls (relative to the WHO child growth standards) were distributed non-normally around a mean of -5.2 cm for boys (range: -7.9 cm to -1.6 cm) and -4.9 cm for girls (range: -7.7 cm to -1.2 cm). Boys exhibited 10% slower linear growth compared with the WHO (range: 19.7% slower to 1.6% faster) and girls 11% slower linear growth compared with the WHO (range: 21.4% slower to 1.0% faster). Variation in the SITAR size parameter was ≥90% explained by the combination of average length within the first 60 days of birth (as a proxy for fetal growth) and intensity, regardless of sex, with much greater contribution by postnatal intensity (r≥0.89 between size and intensity). CONCLUSIONS: SITAR models with two random effects can be used to model child linear growth using multicountry pseudo-longitudinal data, and thereby provide a feasible alternative approach to summarising early childhood height trajectories based on survey data. The SITAR intensity parameter may be a novel indicator for specifically tracking progress in the determinants of postnatal growth in low-income and middle-income countries.

Gaps and priorities in assessment of food environments for children and adolescents in low- and middle-income countries.

School-aged children and adolescents have complex interactions with their food environments-the point of engagement of individuals with the food system-and are influenced by a diversity of individual, household and organizational factors. Although a wide range of methods have been proposed to define, monitor and evaluate food environments, few are tailored to school-aged children and adolescents. Here, we interrogate published literature on food metrics and methodologies for the characterization of food environments for school-aged children and adolescents living in low- and middle-income counties. We identify key priority actions and potential indicators for better monitoring and evaluation to galvanize policymaking to improve the healthiness of these interactions, which are so crucial to future adult well-being.

Anthropometric data quality assessment in multisurvey studies of child growth.

BACKGROUND: Population-based surveys collect crucial data on anthropometric measures to track trends in stunting [height-for-age z score (HAZ) < -2SD] and wasting [weight-for-height z score (WHZ) < -2SD] prevalence among young children globally. However, the quality of the anthropometric data varies between surveys, which may affect population-based estimates of malnutrition. OBJECTIVES: We aimed to develop composite indices of anthropometric data quality for use in multisurvey analysis of child health and nutritional status. METHODS: We used anthropometric data for children 0-59 mo of age from all publicly available Demographic and Health Surveys (DHS) from 2000 onwards. We derived 6 indicators of anthropometric data quality at the survey level, including 1) date of birth completeness, 2) anthropometric measure completeness, 3) digit preference for height and age, 4) difference in mean HAZ by month of birth, 5) proportion of biologically implausible values, and 6) dispersion of HAZ and WHZ distribution. Principal component factor analysis was used to generate a composite index of anthropometric data quality for HAZ and WHZ separately. Surveys were ranked from the highest (best) to the lowest (worst) index values in anthropometric quality across countries and over time. RESULTS: Of the 145 DHS included, the majority (83 of 145; 57%) were conducted in Sub-Saharan Africa. Surveys were ranked from highest to lowest anthropometric data quality relative to other surveys using the composite index for HAZ. Although slightly higher values in recent DHS suggest potential improvements in anthropometric data quality over time, there continues to be substantial heterogeneity in the quality of anthropometric data across surveys. Results were similar for the WHZ data quality index. CONCLUSIONS: A composite index of anthropometric data quality using a parsimonious set of individual indicators can effectively discriminate among surveys with excellent and poor data quality. Such indices can be used to account for variations in anthropometric data quality in multisurvey epidemiologic analyses of child health.

Utility and feasibility of integrating pulse oximetry into the routine assessment of young infants at primary care clinics in Karachi, Pakistan: a cross-sectional study.

BACKGROUND: Hypoxemia may occur in young infants with severe acute illnesses or congenital cardiac anomalies, but is not reliably detected on physical exam. Pulse oximetry (PO) can be used to detect hypoxemia, but its application in low-income countries has been limited, and its feasibility in the routine assessment of young infants (aged 0-59 days) has not been previously studied. The aim of this study was to characterize the operational feasibility and parent/guardian acceptability of incorporating PO into the routine clinical assessment of young infants in a primary care setting in a low-income country. METHODS: This was a cross-sectional study of 862 visits by 529 infants at two primary care clinics in Karachi, Pakistan (March to June, 2013). After clinical assessment, oxygen saturation (Sp02) was measured by a handheld PO device (Rad-5v, Masimo Corporation) according to a standardized protocol. Performance time (PT) was the time between sensor placement and attainment of an acceptable PO reading (i.e., stable SpO2 + 1% for at least 10 s, heart rate displayed, and adequate signal indicators). PT included the time for one repeat attempt at a different anatomical site if the first attempt did not yield an acceptable reading within 1 min. Parent/guardian acceptability of PO was based on a questionnaire and unprompted comments about the procedure. All infants underwent physician assessment. RESULTS: Acceptable PO readings were obtained in ≤ 1 and ≤ 5 min at 94.4% and 99.8% of visits, respectively (n = 862). Median PT was 42 s (interquartile range 37; 50). Parents/guardians overwhelmingly accepted PO (99.6% overall satisfaction, n = 528 first visits). Of 10 infants with at least one visit with Sp02 <92% on a first PO attempt, 3 did not have a significant acute illness on physician assessment. There were no PO-related adverse events. DISCUSSION: Using a commercially available handheld pulse oximeter, acceptable Sp02 measurements were obtained in nearly all infants in under 1 minute. The procedure was readily integrated into existing assessment pathways and parents/guardians had positive views of the technology. CONCLUSIONS: When incorporated into routine clinical assessment of young infants at primary care clinics in a low-income country, PO was feasible and acceptable to parents/guardians. Future research is needed to determine if the introduction of routine PO screening of young infants will improve outcomes in low-resource settings.