Psychomotor Developmental Scores Research Articles

Enteral Zinc Supplementation in Preterm or Low Birth Weight Infants: A Systematic Review and Meta-analysis.

Evidence on the effect of zinc supplementation on health outcomes in preterm or low birth weight (LBW) infants is unclear. We estimated the effect of enteral zinc versus no zinc supplementation in human milk fed preterm or LBW infants on mortality, growth, morbidities, and neurodevelopment. Data sources include PubMed, Cochrane Central and Embase databases through March 24, 2021. Study selection was randomized or quazi-experimental trials. Two reviewers independently screened, extracted data, and assessed quality. We reported pooled relative risks (RR) for categorical outcomes, and mean differences (MD) for continuous outcomes. Fourteen trials with 9940 preterm or LBW infants were included. Moderate to low certainty evidence showed that enteral zinc supplementation had little or no effect on mortality (risk ratio 0.73, 95% confidence interval [CI] 0.46 to 1.16), but increased weight (MD 378.57, 95% CI 275.26 to 481.88), length (MD 2.92, 95% CI 1.53 to 4.31), head growth (MD 0.56, 95% CI 0.23 to 0.90), and decreased diarrhea (RR 0.81; 95% CI 0.68 to 0.97). There was no effect on acute respiratory infections, bacterial sepsis, and psychomotor development scores. The effect of zinc supplementation on mental development scores is inconclusive. There was no evidence of serious adverse events. Eight trials had some concerns or high risk of bias, small-sized studies, and high heterogeneity between trials led to moderate to very low certainty of evidence. Zinc supplementation in preterm or LBW infants have benefits on growth and diarrhea prevention. Further research is needed to generate better quality evidence.

Sibling struggles: the impact of siblings upon child development in rural China

ABSTRACT The goal of the present study is to examine differences in cognitive, psychomotor, and social-emotional development scores between only children and children with siblings aged 6–30 months in rural China using data of 1802 children across 351 villages in 174 townships, disaggregating according to child gender. The results indicate that having a sibling is negatively associated with cognitive, psychomotor, and socioemotional development for girls, but not for boys. Despite this, girls appear to be developmentally advantaged compared to boys, even when they have a sibling. Our results, however, are not conclusive regarding why only-girls are affected while boys are not affected by the existence of siblings. Parenting behaviours (such as playing with children, reading to children, reading to children with books, and singing to children), appear to be unrelated to the developmental differences between only-girls and girls with siblings.

Adverse effects of prenatal mercury exposure on neurodevelopment during the first 3 years of life modified by early growth velocity and prenatal maternal folate level

Background and aimsPrevious studies have suggested that mercury exposure and folate levels during pregnancy may influence early childhood neurodevelopment. Rapid catch-up growth in children is associated with an increased risk of pathological nervous system development. We evaluated whether the association between prenatal folate and mercury-related neuropsychological dysfunction was modified by growth velocity during childhood. MethodsThe Mothers and Children's Environmental Health (MOCEH) birth cohort study began in 2006 and by 2010, 1751 women had been enrolled before the second trimester of their pregnancy along with their partners. Participants visited the research center at birth and 6, 12, 24, and 36 months. We measured mercury levels in maternal and cord blood and folate in maternal serum. Questionnaires to evaluate the environment and health of their child were administered and anthropometric factors including body weight and height were measured. Certified investigators used the Bayley test to measure neurobehavioral outcomes. We calculated postnatal growth change as the change in infant weight for-age z-score between birth and 3 years. Multiple linear regression and mixed models were used to examine the association between mercury exposure and children's neurodevelopment as well as the modifying effects of folate and growth velocity. ResultsA total of 30.6% of children experienced rapid growth during the first 3 years of life. Median values of mercury in the low folate group were significantly higher in rapid growers (3.41 μg/L in maternal blood and 5.63 μg/L in cord blood) than in average/slow growers (3.05 μg/L in maternal blood and 5.19 μg/L in cord blood). Rapid growers were also significantly associated with decreased psychomotor development scores during the first 3 years of life and with having mothers who had low prenatal folate levels, even after adjusting for potential confounders. ConclusionPrenatal mercury exposure adversely affects infant neurodevelopment and is associated with rapid growth during the first 3 years of life. This effect was limited to children whose mothers had low prenatal folate levels, suggesting a protective effect of folate against developmental neurotoxicity due to mercury exposure and rapid catch-up growth.

Childhood neurodevelopment after spontaneous versus indicated preterm birth

Preterm birth is the leading cause of neonatal morbidity and mortality. Individuals who survive preterm birth are at a higher risk for many long-term adverse effects, including neurodevelopmental deficits. There are many well-established risk factors for worse neurologic outcomes spanning the prenatal and postnatal periods; however, investigators have yet to assess whether the cause of preterm birth has an impact on neurodevelopment. Our objective was to assess whether neurologic outcomes differ by children born via indicated versus spontaneous preterm birth. We performed secondary analysis of a multicenter trial assessing magnesium for neuroprotection in women at risk for preterm delivery from 24 to 31 weeks. We included women with live, nonanomalous, singleton gestations who delivered preterm; we excluded women whose children were missing 2-year follow-up information for reasons other than perinatal demise. The primary exposure was type of preterm birth: (1) spontaneous if the child's mother presented with preterm labor or ruptured membranes, or (2) indicated if the child was delivered preterm iatrogenically. The primary outcome was death (including stillbirths, neonatal intensive care unit deaths, and deaths after discharge) or an abnormal Bayley II score by 2 years of age, defined as a Mental Developmental Index score or Psychomotor Developmental Index score 2 standard deviations below the mean. Secondary outcomes included death or Mental Developmental Index and Psychomotor Developmental Index scores 1 standard deviation or less, and neonatal morbidities associated with prematurity. Bivariate analyses of baseline characteristics by exposure were conducted. A logistic regression model was fitted to adjust for confounders. Of 1678 subjects, 1631 (97.2%) underwent spontaneous preterm birth and 47 (2.8%) underwent indicated preterm birth. Baseline maternal demographics and gestational age at delivery were similar between groups (29.6 weeks ± 7.8 versus 28.8 weeks ± 2.5, P= .07). A Psychomotor Developmental Index score 2 standard deviations or less below the mean or death occurred in 340 (20.9%) spontaneous preterm birth subjects and 17 (36.2%) indicated preterm birth subjects (P= .01). When adjusting for confounders, there remained an increased probability of a Psychomotor Developmental Index scores 2 standard deviations or less or death in indicated preterm birth subjects (P= .02). Although not statistically significant, indicated preterm birth was also associated with higher odds of Mental Developmental Index scores 2 standard deviations or less or death, Psychomotor Developmental scores 1 standard deviation or less or death, and Mental Developmental Index scores 1 standard deviation or less or death (1.76, 1.59, and 1.45, respectively). Limiting the analysis to small for gestational age infants, there was no difference in neurologic outcomes. The same was true for when we excluded small for gestational age infants from our analysis. However, after adjusting for small for gestational age, the odds of a Psychomotor Developmental Index score 2 standard deviations or less or death remained significant higher in the indicated preterm birth group (adjusted odds ratio, 1.98; 95% confidence interval, 1.01-3.88). In this cohort of pregnant women who delivered preterm, indicated deliveries were associated with worse psychomotor development than were spontaneous deliveries. Other outcomes appeared to be poor, but our numbers were limited. This finding should be confirmed in a larger cohort of women undergoing medically indicated preterm deliveries.

Prepregnancy obesity is associated with lower psychomotor development scores in boys at age 3 in a low-income, minority birth cohort.

Whether maternal obesity and gestational weight gain (GWG) are associated with early-childhood development in low-income, urban, minority populations, and whether effects differ by child sex remain unknown. This study examined the impact of prepregnancy BMI and GWG on early childhood neurodevelopment in the Columbia Center for Children's Environmental Health Mothers and Newborns study. Maternal prepregnancy weight was obtained by self-report, and GWG was assessed from participant medical charts. At child age 3 years, the Psychomotor Development Index (PDI) and Mental Development Index (MDI) of the Bayley Scales of Infant Intelligence were completed. Sex-stratified linear regression models assessed associations between prepregnancy BMI and pregnancy weight gain z-scores with child PDI and MDI scores, adjusting for covariates. Of 382 women, 48.2% were normal weight before pregnancy, 24.1% overweight, 23.0% obese, and 4.7% underweight. At 3 years, mean scores on the PDI and MDI were higher among girls compared to boys (PDI: 102.3 vs. 97.2, P = 0.0002; MDI: 92.8 vs. 88.3, P = 0.0001). In covariate-adjusted models, maternal obesity was markedly associated with lower PDI scores in boys [b = -7.81, 95% CI: (-13.08, -2.55), P = 0.004], but not girls. Maternal BMI was not associated with MDI in girls or boys, and GWG was not associated with PDI or MDI among either sex (all-P > 0.05). We found that prepregnancy obesity was associated with lower PDI scores at 3 years in boys, but not girls. The mechanisms underlying this sex-specific association remain unclear, but due to elevated obesity exposure in urban populations, further investigation is warranted.

Associations of plasma total phospholipid fatty acid patterns with feeding practices, growth, and psychomotor development in 6-month-old South African infants.

The objective of this study was to assess plasma fatty acid (FA) patterns of 6-month-old South African infants and to determine their association with feeding practices, growth, and psychomotor development. Plasma total phospholipid FA composition (% of total FAs) of 6-month-old infants (n=353) from a peri-urban township was analysed, and principal component and factor analysis were performed to identify plasma FA patterns. Feeding practices, anthropometric measurements, and psychomotor development scores were determined. Four major plasma phospholipid FA patterns were identified: A plant-based C18 FA, a high n-6 long-chain polyunsaturated fatty acids (LCPUFA), a C16:1 and long-chain saturated fatty acid (SFA), and a high n-3 and low n-6 LCPUFA pattern. Formula feeding was associated with higher, whereas breastfeeding was associated with lower scores for the plant-based C18 FA and C16:1 and long-chain SFA patterns. On the other hand, breastfeeding, the consumption of cow's milk, and the consumption of semisolid foods were associated with higher scores, whereas formula feeding was associated with lower scores for the high n-6 LCPUFA pattern. Breastfeeding and the consumption of semisolids were also associated with higher high n-3 and low n-6 LCPUFA pattern scores. The C16:1 and long-chain SFA and high n-3 and low n-6 LCPUFA patterns were positively associated with psychomotor development scores. In 6-month-old South African infants, we identified distinct plasma FA patterns that presumably represent the FA quality of their diet and that are associated with psychomotor development. Our results suggest that breast milk is an important source of n-6 LCPUFAs and formula-fed infants may be at risk of inadequate LCPUFA intake.

Major depressive disorder during pregnancy: Psychiatric medications have minimal effects on the fetus and infant yet development is compromised.

Psychotropic medication use and psychiatric symptoms during pregnancy each are associated with adverse neurodevelopmental outcomes in offspring. Commonly, studies considering medication effects do not adequately assess symptoms, nor evaluate children when the effects are believed to occur, the fetal period. This study examined maternal serotonin reuptake inhibitor and polypharmacy use in relation to serial assessments of five indices of fetal neurobehavior and Bayley Scales of Infant Development at 12 months in N = 161 socioeconomically advantaged, non-Hispanic White women with a shared risk phenotype, diagnosed major depressive disorder. On average fetuses showed the expected development over gestation. In contrast, infant average Bayley psychomotor and mental development scores were low (M = 84.10 and M = 89.92, range of normal limits 85-114) with rates of delay more than 2-3 times what would be expected based on this measure's normative data. Controlling for prenatal and postnatal depressive symptoms, prenatal medication effects on neurobehavioral development were largely undetected in the fetus and infant. Mental health care directed primarily at symptoms may not address the additional psychosocial needs of women parenting infants. Speculatively, prenatal serotonin reuptake inhibitor exposure may act as a plasticity rather than risk factor, potentially enhancing receptivity to a nonoptimal postnatal environment in some mother-infant dyads.

Infant Development at the Age of 6 Months in Relation to Feeding Practices, Iron Status, and Growth in a Peri-Urban Community of South Africa

Background: Evidence on the association between feeding practices, iron deficiency, anaemia, stunting, and impaired psychomotor development during infancy is limited. This study assessed the association between psychomotor development with early feeding practices, growth, iron status, and anaemia. Methods: This was cross-sectional baseline data of a randomised controlled trial which included 6-month-old infants and their mothers or primary caregivers (n = 750) in a peri-urban community in the North West province of South Africa. The Kilifi Developmental Inventory and a parent rating scale were used to assess psychomotor development. Feeding practices and anthropometric measurements were based on the World Health Organisation (WHO) guidelines. Anaemia and iron status were determined by blood sample analysis. Results: Prevalence of anaemia and stunting for the infants were 36.4% and 28.5%, respectively. Multiple regression analysis showed that birth weight was related to combined psychomotor scores (β = −3.427 (−4.603, 1.891), p < 0.001), as well as parent rating scores (β = −0.843 (−1.507, −0.180), p = 0.013). Length-for-age z-scores were associated with combined psychomotor scores (β = −1.419 (−2.466, 0.373), p = 0.008), as well as parent rating scores (β = −0.747 (−1.483, −0.010), p = 0.047). Conclusions: In this setting, with high prevalence of anaemia and stunting, important associations between lower psychomotor development scores and birthweight as well as length-for-age z-scores in 6-month-old infants were found. These findings warrant further investigation to develop a greater understanding of factors influencing the association between child growth and psychomotor development within the first 1000 days of life.

Selenium status during pregnancy: Influential factors and effects on neuropsychological development among Spanish infants

Selenium (Se) has been positively associated with neurodevelopment in early life. However, its margin of safety is rather narrow, and few prospective studies have evaluated its potential neurotoxic effects at intermediate levels. We aimed to explore the association between maternal Se concentrations and child neuropsychological development, including the genetic effect modification of the Se metabolizing gene INMT. Study subjects were 650 mother-child pairs from the Spanish Childhood and Environment Project (INMA, 2003–2005). Infant neuropsychological development was assessed around 12months of age by the Bayley Scales of Infant Development. Sociodemographic and dietary characteristics were collected by questionnaire at the first and third trimester of gestation. Se was measured in serum samples at the first trimester. The mean serum Se concentration was 79.7 (standard deviation=7.9) μg/L. In multivariate analysis, nonsignificant inverse linear associations were found between Se concentrations and standardized mental and psychomotor development scores (β (95% CI)=−0.13 (−0.29, 0.03) and β (95% CI)=−0.08 (−0.24, 0.07), respectively). Generalized additive models indicated inverted U-shaped relationships between Se concentrations and both scales. Using segmented regression, the turning point for the associations was estimated at 86μg/L for both scales. The association between Se and neuropsychological development was inverted U-shaped for children with the AG+AA genotype for rs6970396 INMT but a descending curve was suggested for the GG genotype. Further studies would be necessary in order to disentangle the complex equilibrium between the toxicity and benefits of Se exposure during the prenatal period.

Effects of Nutrient-Fortified Milk-Based Formula on the Nutritional Status and Psychomotor Skills of Preschool Children

This randomized, single-masked, controlled trial examined the effects of nutrient-fortified milk-based formula supplementation on nutritional status, nutrient intake, and psychomotor skills of selected preschool children with mean age of 4.10 ± 0.14 years. The study participants were divided equally into three major groups, normal, underweight, and severely underweight based on WHO-Child Growth Standards, and were further divided into two groups: fortified milk group who was given two glasses of fortified milk (50 g of powdered milk/serving) a day for twelve weeks in addition to their usual diet and the nonintervention group who was not given fortified milk and thus maintained their usual intake. Anthropometric measurements, dietary intake, and psychomotor developmental score were analyzed. Results showed that consumption of two servings of fortified milk a day for twelve weeks significantly increased the height of preschool children by 1.40 cm, weight by 1.35 kg, body mass index by 0.96 kg/m2, mid-upper arm circumference by 0.66 cm, and psychomotor scores by 13.74% more than those children who did not consume fortified milk (p < 0.0001). Hence, fortified milk-based supplement in the diet of preschool children improved overall nutritional status, nutrient intake, and performance in psychomotor scale. This study is registered in Philippine Health Research Registry: PHRR140923-000234.

Iodine status and associations with feeding practices and psychomotor milestone development in six-month-old South African infants.

Iodine is important for normal growth and psychomotor development. While infants below 6months of age receive iodine from breast milk or fortified infant formula, the introduction of complementary foods poses a serious risk for deteriorating iodine status. This cross-sectional analysis assessed the iodine status of six-month-old South African infants and explored its associations with feeding practices and psychomotor milestone development. Iodine concentrations were measured in infant (n=386) and maternal (n=371) urine (urinary iodine concentration [UIC]), and in breast milk (n=257 [breast milk iodine concentrations]). Feeding practices and psychomotor milestone development were assessed in all infants. The median (25th-75th percentile) UIC in infants was 345 (213-596) μg/L and was significantly lower in stunted (302 [195-504] μg/L) than non-stunted (366 [225-641] μg/L) infants. Only 6.7% of infants were deficient. Maternal UIC (128 [81-216] μg/L; rs =0.218, p<0.001) and breast milk iodine concentrations (170 [110-270] μg/kg; rs =0.447, p<0.0001) were associated with infant UIC. Most infants (72%) were breastfed and tended to have higher UIC than non-breastfed infants (p=0.074). Almost all infants (95%) consumed semi-solid or solid foods, with commercial infant cereals (60%) and jarred infant foods (20%) being the most common solid foods first introduced. Infants who reported to consume commercial infant cereals ≥4days weekly had significantly higher UIC (372 [225-637] μg/L) than those reported to consume commercial infant cereals seldom or never (308 [200-517] μg/L; p=0.023). No associations between infant UIC and psychomotor developmental scores were observed. Our results suggest that iodine intake in the studied six-month-old infants was adequate. Iodine in breast milk and commercial infant cereals potentially contributed to this adequate intake.

Moderately elevated maternal homocysteine at preconception is inversely associated with cognitive performance in children 4 months and 6 years after birth.

Prenatal methyl donor deficiency leads to homocysteine accumulation in the brain and impaired neurodevelopment in rats. We investigated the effect of moderately elevated preconception fasting total plasma homocysteine (tHcy) on child neurodevelopment in a prospective study of 67 and 76 mother-child pairs at 4 months and 6 years of age, respectively. Fasting blood samples at 2-10 weeks preconception, from the cord (nonfasting) and the mother and child 6 years after birth, were collected. Psychomotor and mental development were assessed at 4 months using the Bayley Scale of Infant Development (BSID) and cognitive development at 6 years using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI). Highest tertile preconception tHcy (≥9.04 µmol/L) was categorized as moderately elevated and low-mid tertile tHcy as normal. Children, born to mothers with moderately elevated compared to normal preconception tHcy, scored lower [mean (95% CI)] in the BSID psychomotor [115 (105, 124) vs. 126 (121, 130), p = 0.03] and mental [101 (93, 109) vs. 113 (107, 119), p = 0.03] development tests. Multiple logistic regression analysis showed that moderately elevated compared to normal preconception tHcy was associated with greater probability, OR (95%CI), of scoring in the lowest tertile for BSID psychomotor development (≤120): 4.0 (1.1, 14.3) and lowest tertiles for WPPSI full (≤111), verbal (≤104) and performance (≤111), intellectual quotient: 6.0 (1.5, 23.7), 3.5 (1.1, 11.2) and 4.1 (1.1, 15.7), respectively. We conclude that moderately elevated preconception tHcy is inversely associated with psychomotor and cognitive development scores in infants and children.

Developmental Scores at 1 Year With Increasing Gestational Age, 37–41 Weeks

To examine the relationship between gestational age and mental and psychomotor development scores in healthy infants born between 37 and 41 weeks. The cohort included 1562 participants enrolled during infancy in an iron deficiency anemia preventive trial in Santiago, Chile. All participants were healthy, full-term (37-41 weeks) infants who weighed 3 kg or more at birth. Development at 12 months was assessed using the Bayley Scales of Infant Development. Using generalized linear modeling, we analyzed the association between gestational age and 1-year-old developmental status, taking into account potential confounders including birth weight percentile, gender, socioeconomic status, the home environment, iron status, and iron supplementation. For each additional week of gestation, the Mental Development Index increased by 0.8 points (95% confidence interval = 0.2-1.4), and the Psychomotor Development Index increased by 1.4 points (95% confidence interval = 0.6-2.1) controlling for birth weight percentile, gender, socioeconomic status, and home environment. In a large sample of healthy full-term infants, developmental scores obtained using the Bayley Scales of Infant Development at 12 months increased with gestational age (37-41 weeks). There is increasing evidence that birth at 39 to 41 weeks provides developmental advantages compared with birth at 37 to 38 weeks. Because cesarean deliveries and early-term inductions have increased to 40% of all births, consideration of ongoing brain development during the full-term period is an important medical and policy issue.

Maternal pre-pregnancy overweight and obesity, and child neuropsychological development: two Southern European birth cohort studies

Maternal pre-pregnancy obesity may be associated with impaired infant neuropsychological development; however, there are few studies and it is unclear if reported associations are due to intrauterine mechanisms. We assessed whether maternal pre-pregnancy overweight and obesity were associated with cognitive and psychomotor development scores (mean 100 ± 15) of children aged 11-22 months in two birth cohorts: Environment and Childhood (INMA, Spain; n = 1967) and Mother-Child (RHEA, Greece: n = 412). Paternal body mass index (BMI) was used as a negative control exposure. The percentage of overweight and obese mothers was 18% and 8%, respectively, in INMA and 20% and 11% in RHEA, respectively. Maternal pre-pregnancy obesity was associated with reduced infant cognitive development scores in both INMA (score reduction: -2.72; 95% CI: -5.35, -0.10) and RHEA (score reduction: -3.71; 95% CI: -8.45, 1.02), after adjusting for socioeconomic variables and paternal BMI. There was evidence in both cohorts of a dose-response relationship with continuous maternal BMI. Paternal overweight/obesity was not associated with infant cognitive development. Associations with psychomotor scores were not consistent between cohorts, and were stronger for paternal than maternal BMI in RHEA. This study in two birth cohorts with moderately high obesity prevalence suggests that maternal pre-pregnancy obesity is associated with reduced child cognitive development at early ages. This association appears more likely to be due to maternal than shared family and social mechanisms, but further research is needed to disentangle a direct intrauterine effect from other maternal confounding factors.

Evaluating the neurotoxic effects of lactational exposure to persistent organic pollutants (POPs) in Spanish children

Although the brain continues developing in the postnatal period, epidemiological studies on the effects of postnatal exposure to neurotoxic POPs through breast-feeding remain mostly inconclusive. Failure to detect associations between postnatal exposure and health outcomes may stem from the limitations of commonly employed approaches to assess lactational exposure. The aim of the present study was to assess whether lactational exposure to polychlorinated biphenyl-153 (PCB-153), dichlorodiphenyldichloroethylene (DDE), or hexachlorobenzene (HCB) as estimated with a physiologically based pharmacokinetic (PBPK) model, is associated with decrements in mental and psychomotor development scores of the Bayley Scales of Infant Development (BSID) test in children aged around 14-months of a subsample (N=1175) of the Spanish INMA birth cohort, and to compare this with the effects of prenatal exposure. Although in the present study population PCB-153, DDE and HCB exposure increased within the first months of postnatal life, no associations were found between different periods of postnatal exposure to these compounds and mental or psychomotor scores. Increasing prenatal PCB-153 concentrations were associated with worse mental and psychomotor scores, although significance was only reached for psychomotor development (β [95%CI]=−1.36 [−2.61, −0.11]). Indeed, the association between exposure and effects observed during prenatal life weakened gradually across periods of postnatal life. Results of the present study suggest that, although breastfeeding increases children's blood persistent organic pollutants (POPs) levels during postnatal life, deleterious effects of PCB-153 on neuropsychological development are mainly attributable to prenatal exposure.

In-Utero Exposure to Dichlorodiphenyltrichloroethane and Cognitive Development Among Infants and School-aged Children

Dichlorodiphenyltrichloroethane (DDT) continues to be used for control of infectious diseases in several countries. In-utero exposure to DDT and dichlorodiphenyldichloroethylene (DDE) has been associated with developmental and cognitive impairment among children. We examined this association in an historical cohort in which the level of exposure was greater than in previous studies. The association of in-utero DDT and DDE exposure with infant and child neurodevelopment was examined in 1100 subjects in the Collaborative Perinatal Project, a prospective birth cohort enrolling pregnant women from 12 study centers in the United States from 1959 to 1965. Maternal DDT and DDE concentrations were measured in archived serum specimens. Infant mental and motor development was assessed at age 8 months using the Bayley Scales of Infant Development, and child cognitive development was assessed at age 7 years, using the Wechsler Intelligence Scale for Children. Although levels of DDT and DDE were relatively high in this population (median DDT concentration, 8.9 μg/L; DDE, 24.5 μg/L), neither were related to Mental or Psychomotor Development scores on the Bayley Scales nor to Full-Scale Intelligence Quotient at 7 years of age. Categorical analyses showed no evidence of dose- response for either maternal DDT or DDE, and estimates of the association between continuous measures of exposure and neurodevelopment were indistinguishable from 0. Adverse associations were not observed between maternal serum DDT and DDE concentrations and offspring neurodevelopment at 8 months or 7 years in this cohort.

Mixed Metals Toxicity: More than the Sum of Its Parts?

Most toxicologic studies focus on one chemical or toxicant at a time, although in the real world people are exposed to multiple substances at once. Metals, for example, are commonly found in combinations in air, water, and food. Now researchers have conducted a prospective epidemiologic study to examine neurodevelopmental effects of manganese–lead coexposure [EHP 120(1):126–131; Claus Henn et al.]. The study included 455 children enrolled at birth in a Mexico City longitudinal cohort study, who were followed until 36 months of age. The researchers measured blood levels of lead and manganese at 12 and 24 months of age. Cognitive, motor, and language development were assessed every 6 months from 12 to 36 months of age using the Bayley Scales of Infant Development–II. Both lead and manganese exert their toxic effects on child development primarily through the central nervous system. Exposure to manganese and lead simultaneously was associated with greater deficits in both mental and psychomotor development than expected based on the estimated effects of exposure to either metal alone; this is consistent with a synergistic effect on neurodevelopment. Associations were greatest at 12 months, where Mental Development Index scores were 2.16 points lower per 1-unit increase in blood lead among children with high manganese compared with children with midrange manganese. Psychomotor Development Index scores at 12 months were 0.97 points lower per 1-unit increase in blood lead among children with high manganese compared with children with midrange manganese. The authors suggest that the developmental period up to 12 months may be particularly sensitive to this interaction. The differences in mental and psychomotor development scores were small for individuals, but the authors write that these differences may have population-level consequences if they cause the entire distribution of neurodevelopment scores to shift. This would increase the number of children eligible for diagnosis with neurodevelopmental problems (who would then require treatment) as well as decrease the average IQ. The study’s strengths include a stable study population with little attrition as well as the repeated measurements of neurodevelopment between 12 and 36 months, which allowed the researchers to evaluate associations over time and offered greater statistical power than cross-sectional analyses. Weaknesses of the study included the lack of formal exposure assessment, which means the sources of metal exposure were unknown. In addition, the neurodevelopment test instruments used in the study were not normalized to the Mexican population, so the resulting scores are relatively low compared with the expected mean score of 100 in a U.S. population and cannot be generalized to other populations.

Examination of the cut-off scores determined by the Ages and Stages Questionnaire in a population-based sample of 6 month-old Norwegian infants

BackgroundFew population-based samples have previously published performance on the Ages and Stages Questionnaire (ASQ), a recommended screening tool to detect infant developmental delay. The aim of the study was to investigate performance on the ASQ in a population-based sample of 6-month-old infants.MethodsIn this population-based questionnaire study from Oslo, Norway, the 30 item ASQ 6 month Questionnaire (N = 1053) were included, however without the pictograms, and compared to the Norwegian reference sample (N.ref) (N = 169) and to US cut-off values. Exclusion criteria were maternal non-Scandinavian ethnicity, infant age < 5.0 or > 7.0 months (corrected age), twins, and birth weight < 2.5 kg. Cut-off = 2.5 percentile (equivalent to mean minus 2 standard deviations). Pearson's Chi square and Mann-Whitney U were used to compare items and areas, respectively, with N.ref.ResultsThe reported ASQ scores were lower on all but one of the 10 significantly different items, and in all areas except Personal social, compared to the N.ref sample. The estimated cut-off values for suspected developmental delay (Communication 25, Gross motor 15, Fine motor 18, Problem solving 25 and Personal social 20) were lower than the recommended American (US) values in all areas, and lower than the Norwegian values in two areas. Scores indicating need for further assessment were reached by 13.8% or 20.5% of the infants (missing items scored according to the US or the Norwegian manual), and by 33.8% or 30.3% of the infants using the recommended US or the Norwegian cut-off values, in this population-based sample. The Fine motor area demonstrated a large variability depending on the different cut-off and scoring possibilities. Both among the items excluding pictograms and the items that do not have pictograms, approximately every third item differed significantly compared to the N.ref sample.ConclusionThe psychomotor developmental scores were lower than in the reference samples in this study of ASQ 6 month Questionnaire; to our knowledge the first study to be both representative and comparatively large. Approximately every third child with birth weight above 2.5 kg, received scores suggesting further assessment using recommended ASQ cut-off scores.

Associations of Early Childhood Manganese and Lead Coexposure with Neurodevelopment

Background: Most toxicologic studies focus on a single agent, although this does not reflect real-world scenarios in which humans are exposed to multiple chemicals.Objectives: We prospectively studied manganese–lead interactions in early childhood to examine whether manganese–lead coexposure is associated with neurodevelopmental deficiencies that are more severe than expected based on effects of exposure to each metal alone.Methods: Four hundred fifty-five children were enrolled at birth in an longitudinal cohort study in Mexico City, provided blood samples, and were followed until 36 months of age. We measured lead and manganese at 12 and 24 months and assessed neurodevelopment at 6-month intervals from 12 to 36 months of age using Bayley Scales of Infant Development–II.Results: Mean (± SD) blood concentrations at 12 and 24 months were, respectively, 24.7 ± 5.9 μg/L and 21.5 ± 7.4 μg/L for manganese and 5.1 ± 2.6 μg/dL and 5.0 ± 2.9 μg/dL for lead. Mixed-effects models, including Bayley scores at five time points, showed a significant interaction over time: highest manganese quintile × continuous lead; mental development score, β = –1.27 [95% confidence interval (CI): –2.18, –0.37]; psychomotor development score, β = –0.92 (95% CI: –1.76, –0.09). Slopes for the estimated 12-month lead effect on 18-month mental development and 24- through 36-month psychomotor development scores were steeper for children with high manganese than for children with midrange manganese levels.Conclusions: We observed evidence of synergism between lead and manganese, whereby lead toxicity was increased among children with high manganese coexposure. Findings highlight the importance of understanding health effects of mixed exposures, particularly during potentially sensitive developmental stages such as early childhood.

The Impact of Nutritional Status and Longitudinal Recovery of Motor and Cognitive Milestones in Internationally Adopted Children

Internationally adopted children often arrive from institutional settings where they have experienced medical, nutritional and psychosocial deprivation. This study uses a validated research assessment tool to prospectively assess the impact of baseline (immediately post adoption) nutritional status on fifty-eight children as measured by weight-for-age, height-for-age, weight-for-height and head circumference-for-age z scores, as a determinant of cognitive (MDI) and psychomotor development (PDI) scores longitudinally. A statistical model was developed to allow for different ages at time of initial assessment as well as variable intervals between follow up visits. The study results show that both acute and chronic measures of malnutrition significantly affect baseline developmental status as well as the rate of improvement in both MDI and PDI scores. This study contributes to the body of literature with its prospective nature, unique statistical model for longitudinal evaluation, and use of a validated assessment tool to assess outcomes.