Decomposing the social gradient in children's vocabulary skills at 3 years of age: A mediation analysis using data from a large representative cohort study

Genetic outcomes in children with developmental language disorder: a systematic review

Introduction

Developmental language disorder (DLD) is a common childhood condition negatively influencing communication and psychosocial development. An increasing number of pathogenic variants or chromosomal anomalies possibly related to DLD have been identified. To provide a base for accurate clinical genetic diagnostic work-up for DLD patients, understanding the specific genetic background is crucial. This study aims to give a systematic literature overview of pathogenic variants or chromosomal anomalies causative for DLD in children.

Methods

We conducted a systematic search in PubMed and Embase on available literature related to the genetic background of diagnosed DLD in children. Included papers were critically appraised before data extraction. An additional search in OMIM was performed to see if the described DLD genes are associated with a broader clinical spectrum.

Results

The search resulted in 15,842 papers. After assessing eligibility, 47 studies remained, of which 25 studies related to sex chromosome aneuploidies and 15 papers concerned other chromosomal anomalies (SCAs) and/or Copy Number Variants (CNVs), including del15q13.1-13.3 and del16p11.2. The remaining 7 studies displayed a variety of gene variants. 45 (candidate) genes related to language development, including FOXP2, GRIN2A, ERC1, and ATP2C2. After an additional search in the OMIM database, 22 of these genes were associated with a genetic disorder with a broader clinical spectrum, including intellectual disability, epilepsy, and/or autism.

Conclusion

Our study illustrates that DLD can be related to SCAs and specific CNV's. The reported (candidate) genes (n = 45) in the latter category reflect the genetic heterogeneity and support DLD without any comorbidities and syndromic language disorder have an overlapping genetic etiology.

Relationships between maternal body mass index and child cognitive outcomes at 3 years of age are buffered by specific early environments in a prospective Canadian birth cohort

Fetal and child development are shaped by early life exposures, including maternal health states, nutrition and educational and home environments. We aimed to determine if suboptimal pre-pregnancy maternal body mass index (BMI; underweight, overweight, obese) would associate with poorer cognitive outcomes in children, and whether early life nutritional, educational and home environments modify these relationships. Self-reported data were obtained from mother-infant dyads from the pan-Canadian prospective Maternal-Infant Research on Environmental Chemicals cohort. Relationships between potential risk factors (pre-pregnancy maternal BMI, breastfeeding practices and Home Observation Measurement of the Environment [HOME] score) and child cognitive development at age three (Weschler's Preschool and Primary Scale of Intelligence, Third Edition scale and its subcategories) were each evaluated using analysis of variance, multivariable regression models and moderating analyses. Amongst the 528 mother-child dyads, increasing maternal pre-pregnancy BMI was negatively associated with scores for child full-scale IQ (β [95% CI]; -2.01 [-3.43, -0.59], p = 0.006), verbal composite (-1.93 [-3.33, -0.53], p = 0.007), and information scale (-0.41 [-0.70, -0.14], p = 0.003) scores. Higher maternal education level or HOME score attenuated the negative association between maternal pre-pregnancy BMI and child cognitive outcome by 30%-41% and 7%-22%, respectively, and accounted for approximately 5%-10% greater variation in male children's cognitive scores compared to females. Maternal education and higher quality home environment buffer the negative effect of elevated maternal pre-pregnancy BMI on child cognitive outcomes. Findings suggest that relationships between maternal, social and environmental factors must be considered to reveal pathways that shape risk for, and resiliency against, suboptimal cognitive outcomes in early life.

Explaining gaps by parental education in children’s early language and social outcomes at age 3–4 years: evidence from harmonised data from three countries

Child outcomes vary by family’s socioeconomic status (SES). Research on explanatory factors underlying early SES-related disparities has mainly focused on specific child outcomes (e.g., language skills) and selected influencing factors in single countries often with a focus on individual differences but not explicitly on early SES-related gaps. This study uses harmonised data from longitudinal large-scale studies conducted in the United Kingdom, United States, and Germany to examine parental education-related gaps in early child language and social skills. Twelve theoretically proposed family-, child-, and childcare-related factors were systematically evaluated as explanatory factors. In all countries, parental education-related gaps were particularly pronounced for early child language compared to social skills. In the decomposition analyses, the home learning environment was the only measure that significantly explained gaps in all child outcomes across all countries. Early centre-based care attendance, family income, and maternal age at childbirth contributed to gaps in child outcomes with the specific pattern of results varying across outcomes and countries. Maternal depressive feelings significantly contributed only to explaining gaps in children’s social skills. Thus, while some mechanisms found to underpin early parental education-related gaps can be generalized from single-country, single-domain studies, others are outcome- and context-specific.

Sociocultural Factors Affecting Vocabulary Development in Young South African Children

Sociocultural influences on the development of child language skills have been widely studied, but the majority of the research findings were generated in Northern contexts. The current crosslinguistic, multisite study is the first of its kind in South Africa, considering the influence of a range of individual and sociocultural factors on expressive vocabulary size of young children. Caregivers of toddlers aged 16 to 32 months acquiring Afrikaans (n = 110), isiXhosa (n = 115), South African English (n = 105), or Xitsonga (n = 98) as home language completed a family background questionnaire and the MacArthur-Bates Communicative Development Inventory (CDI) about their children. Based on a revised version of Bronfenbrenner’s (1977) ecological systems theory, information was obtained from the family background questionnaire on individual factors (the child’s age and sex), microsystem-related factors (the number of other children and number of adults in the child’s household, maternal level of education, and SES), and exosystem-related factors (home language and geographic area, namely rural or urban). All sociocultural and individual factors combined explained 25% of the variance in expressive vocabulary size. Partial correlations between these sociocultural factors and the toddlers’ expressive vocabulary scores on 10 semantic domains yielded important insights into the impact of geographic area on the nature and size of children’s expressive vocabulary. Unlike in previous studies, maternal level of education and SES did not play a significant role in predicting children’s expressive vocabulary scores. These results indicate that there exists an interplay of sociocultural and individual influences on vocabulary development that requires a more complex ecological model of language development to understand the interaction between various sociocultural factors in diverse contexts.

Maternal education and language development at 2 years corrected age in children born very preterm: results from a European population-based cohort study

BACKGROUND

Socioeconomic factors influence language development in the general population, but the association remains poorly documented in children born very preterm (VPT). We assessed the impact of maternal education on language development in children born VPT and effect modification by perinatal risk.

METHODS

Data were from the Effective Perinatal Intensive Care in Europe (EPICE) population-based cohort of children born <32 weeks' gestational age (GA) in 2011/2012. Regions from six countries (Estonia, France, Germany, Italy, Sweden and UK) used a validated short form MacArthur Developmental Communicative Inventories Checklist to assess language at 2 years corrected age. Perinatal variables were collected from clinical records. We assessed expressive language delay (ELD), defined as (a) not combining words; and (b) expressive vocabulary <10th percentile of norms for age and sex. Perinatal risk (low, moderate and high) was determined using GA, small for GA and neonatal morbidities. We estimated adjusted risk ratios (aRR) of ELD by maternal education with inverse weighting to account for non-response bias.

RESULTS

Of 2741 children, 24.6% were not combining words and 39.7% had a low expressive vocabulary. Low maternal education (lower secondary or less compared with a bachelor's degree or more) increased risks of ELD: not combining words: aRR=1.52 (95% CI 1.36 to 1.69); low expressive vocabulary: aRR=1.25 (1.04 to 1.51). For children with low perinatal risk, the aRR were 1.88 (1.26 to 2.80) and 1.44 (1.06 to 1.95), respectively, compared with those with high perinatal risks: 1.36 (1.10 to 1.67) and 1.11 (0.97 to 1.27), respectively.

CONCLUSION

Low maternal education affects ELD for children born VPT, although the association appears attenuated among those with highest perinatal risk.