Head circumference may be the best proxy for neurodevelopmental risk in children in low-resource settings

Kindergarten dust heavy metal(loid) exposure associates with growth retardation in children

Heavy metal contamination from electronic waste recycling sites is present in dust found in indoor kindergartens located in e-waste recycling areas, and its potential impact on child health is a significant concern. The association between heavy metal(loid)s and the child developmental indicators is still unclear. In 2019 and 2020, we enrolled 325 and 319 children in an e-waste recycling town, respectively. Corresponding 61 and 121 dust samples were collected from roads, houses, and kindergartens in the two years. The median concentrations of metals, including Cr, Ni, Cu, Zn, and Pb exceeded the allowable limits. The highest amount of cumulative enrichment (cEF) was observed in indoor kindergarten dust (cEF = 112.3400), followed by house dust (cEF = 76.6950) and road dust (cEF = 39.7700). Children residing in the e-waste town had below-average height and weight compared to their Chinese peers. Based on linear regression analysis, the daily intake of Cd, V, Mn, and Pb in indoor kindergarten dust was found to be negatively associated with head circumference (HeC) (P < 0.05). Similarly, the daily intake of As, Cd, and Ba in indoor kindergarten dust was found to be negatively associated with chest circumference (ChC) (P < 0.05). In addition, the daily intake of As, Cd, and Ba in indoor kindergarten dust was negatively correlated with body mass index (BMI), as per the results of the study (P < 0.05). Cross-product term analysis revealed a negative correlation between daily intake of heavy metal(loid)s and HeC, ChC, and BMI, with age and sex serving as influencing factors. In conclusion, exposure to heavy metal(loid)s in indoor kindergarten dust increases the risk of growth retardation and developmental delay in children.

Cumulative Febrile, Respiratory, and Gastrointestinal Illness Among Infants in Rural Guatemala and Association With Neurodevelopmental and Growth Outcomes

BACKGROUND

Infectious disease exposures in early life are increasingly recognized as a risk factor for poor subsequent growth and neurodevelopment. We aimed to evaluate the association between cumulative illness with neurodevelopment and growth outcomes in a birth cohort of Guatemalan infants.

METHODS

From June 2017 to July 2018, infants 0-3 months of age living in a resource-limited region of rural southwest Guatemala were enrolled and underwent weekly at-home surveillance for caregiver-reported cough, fever, and vomiting/diarrhea. They also underwent anthropometric assessments and neurodevelopmental testing with the Mullen Scales of Early Learning (MSEL) at enrollment, 6 months, and 1 year.

RESULTS

Of 499 enrolled infants, 430 (86.2%) completed all study procedures and were included in the analysis. At 12-15 months of age, 140 (32.6%) infants had stunting (length-for-age Z [LAZ] score < -2 SD) and 72 (16.7%) had microcephaly (occipital-frontal circumference [OFC] < -2 SD). In multivariable analysis, greater cumulative instances of reported cough illness (beta = -0.08/illness-week, P = 0.06) and febrile illness (beta = -0.36/illness-week, P < 0.001) were marginally or significantly associated with lower MSEL Early Learning Composite (ELC) Score at 12-15 months, respectively; there was no association with any illness (cough, fever, and/or vomiting/diarrhea; P = 0.27) or with cumulative instances of diarrheal/vomiting illness alone ( P = 0.66). No association was shown between cumulative instances of illness and stunting or microcephaly at 12-15 months.

CONCLUSIONS

These findings highlight the negative cumulative consequences of frequent febrile and respiratory illness on neurodevelopment during infancy. Future studies should explore pathogen-specific illnesses, host response associated with these syndromic illnesses, and their association with neurodevelopment.

Anthropometric proxies for child neurodevelopment in low-resource settings: length- or height-for-age, head circumference or both?

Stunting (<-2 SD of length- or height-for-age on WHO growth curves) is the most used predictor of child neurodevelopmental (ND) risk. Occipitofrontal head circumference (OFC) may be an equally feasible, but more direct and robust predictor. We explored association of the two measurements with ND outcome, separately and combined, and examined if cutoffs are more efficacious than continuous measures in predicting ND risk. Infants and young children in rural Guatemala (n = 642; age range = 0.1-35.9 months) were enrolled in a prospective natural history study, and their ND was tested using the Mullen Scales of Early Learning (MSEL) longitudinally. Length- or height-for-age and OFC-for-age were calculated. We performed age-adjusted multivariable regression analyses to explore the association between 1) length or height and ND, 2) OFC and ND, and 3) both length or height and OFC combined, with ND; concurrently, predictively, and longitudinally, as continuous variables and using WHO z-score cutoffs. Continuous length- or height-for-age and OFC z-scores were more strongly associated with MSEL than the traditional -2 SD WHO cutoff. The combination of height-for-age z-score and OFC z-score was consistently, strongly associated with the MSEL Early Learning Composite concurrently (p-values 0.0004-0.11), predictively (p-value 0.001-0.07), with the exception of the 18-24 months age group which had very few records, and in the longitudinal model (p-value <0.0001-0.004). The combination of continuous length- or height-for-age and OFC shows additional utility in estimating ND risk in infants and young children. Measurement of OFC may improve precision of prediction of ND risk in infants and young children.

Head circumference as an epigenetic risk factor for maternal nutrition

Nutrition indicators for malnutrition can be screened by many signs such as stunting, underweight or obesity, muscle wasting, and low caloric and nutrients intake. Those deficiencies are also associated with low socioeconomic status. Anthropometry can assess nutritional status by maternal weight measurements during pregnancy. However, most studies have focused primarily on identifying changes in weight or Body Mass Index (BMI), and their effects on neonatal measures at present time. Whereas head circumference (HC) has been associated with nutrition in the past. When the mother was exposed to poor nutrition and unfavorable social conditions during fetal life, it was hypothesized that the intergenerational cycle was potentially mediated by epigenetic mechanisms. To investigate this theory, maternal head circumference (MHC) was associated with neonatal head circumference (NHC) in pregnant women without preexisting chronic conditions, differentiated by sociodemographic characteristics. A multiple linear regression model showed that each 1 cm-increase in MHC correlated with a 0.11 cm increase in NHC (β95% CI 0.07 to 0.15). Notwithstanding, associations between maternal and neonatal anthropometrics according to gestational age at birth have been extensively explained. Path analysis showed the influence of social status and the latent variable was socioeconomic status. A model of maternal height and head circumference was tested with effects on neonatal HC. The social variable lacked significance to predict neonatal HC in the total sample (p = 0.212) and in the South/Southeast (p = 0.095), in contrast to the Northeast (p = 0.047). This study highlights the potential intergenerational influence of maternal nutrition on HC, suggesting that maternal nutrition may be more relevant in families with major social vulnerability.