Association between prenatal or early postnatal exposure to perfluoroalkyl substances and language development in 18 to 36-month-old children from the Odense Child Cohort.

BACKGROUND: Perfluoroalkyl substances (PFAS) are persistent chemicals used in everyday consumer products leading to ubiquitous human exposure. Findings of impaired neurodevelopment after prenatal exposure to PFAS are contradictory and few studies have assessed the impact of postnatal PFAS exposure. Language development is a good early marker of neurodevelopment but only few studies have investigated this outcome separately. We therefore investigated the association between prenatal and early postnatal PFAS exposure and delayed language development in 18 to 36-month-old Danish children. METHODS: The Odense Child Cohort is a large prospective cohort. From 2010 to 2012 all newly pregnant women residing in the Municipality of Odense, Denmark was invited to participate. Concentration of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were assessed in maternal serum collected in the 1st trimester of pregnancy and in child serum at 18 months. Parents responded to the Danish adaption of the MacArthur-Bates Communicative Development Inventories (MB-CDI) when their child was between 18 and 36 months. Language scores were converted into sex and age specific percentile scores and dichotomized to represent language scores above or below the 15th percentile. We applied Multiple Imputation by Chained Equation and conducted logistic regressions investigating the association between prenatal and early postnatal PFAS exposure and language development adjusting for maternal age, pre-pregnancy BMI, education and respectively fish intake in pregnancy or childhood and duration of breastfeeding in early postnatal PFAS exposure models. RESULTS: We found no significant associations between neither prenatal nor early postnatal PFAS exposure and language development among 999 mother-child pairs. CONCLUSION: In this low-exposed cohort the finding of no association between early postnatal PFAS exposure and language development should be interpreted with caution as we were unable to separate the potential adverse effect of PFAS exposure from the well documented positive effect of breastfeeding on neurodevelopment. We, therefore, recommend assessment of child serum PFAS at an older age as development of the brain proceeds through childhood and even a small impact of PFAS on neurodevelopment would be of public health concern at population level due to the ubiquitous human exposure.

Danish 20-month-olds' recognition of familiar words with and without consonant and vowel mispronunciations.

Although several studies initially supported the proposal by Nespor et al. (Nespor, Marina, Marcela Peña & Jacques Mehler. 2003. On the different roles of vowels and consonants in speech processing and language acquisition. Lingue e Linguaggio 2. 221-247) that consonants are more informative than vowels in lexical processing, a more complex picture has emerged from recent research. Current evidence suggests that infants initially show a vowel bias in lexical processing and later transition to a consonant bias, possibly depending on the characteristics of the ambient language. Danish infants have shown a vowel bias in word learning at 20 months-an age at which infants learning French or Italian no longer show a vowel bias but rather a consonant bias, and infants learning English show no bias. The present study tested whether Danish 20-month-olds also have a vowel bias when recognizing familiar words. Specifically, using the Intermodal Preferential Looking paradigm, we tested whether Danish infants were more likely to ignore or accept consonant than vowel mispronunciations when matching familiar words with pictures. The infants successfully matched correctly pronounced familiar words with pictures but showed no vowel or consonant bias when matching mispronounced words with pictures. The lack of a bias for Danish vowels or consonants in familiar word recognition adds to evidence that lexical processing biases are language-specific and may additionally depend on developmental age and perhaps task difficulty.

Prenatal bisphenol A exposure is associated with language development but not with ADHD-related behavior in toddlers from the Odense Child Cohort.

Bisphenol A (BPA) is a non-persistent chemical with endocrine disrupting abilities widely used in a variety of consumer products. The fetal brain is particularly sensitive to chemical exposures due to its rapid growth and complexity. Some studies have reported associationbetween maternal BPA exposure and behavior but few have assessed impact on cognitive development, and to our knowledge no studies have specifically assessed the impact on language development. We therefore assessed whether maternal urinary BPA concentration during pregnancy was associated with language development and attention-deficit and hyperactivity disorder (ADHD) symptoms in offspring aged 18-36 months in the prospective Odense Child Cohort. BPA was analyzed in 3rd trimester maternal fasting urine spot samples. Language development was addressed among 535 children using the Danish adaptation of the MacArthur-Bates Communicative Development Inventories at median age 21 months; ADHD traits were assessed by parents of 658 children using the Child Behavior Checklist for ages 1½-5 years at mean age 2.7 years. Associations were assessed using logistic regression models comparing children below the 15th percentile score for language and above the 85 percentiles score for ADHD with the other children while stratifying by sex and adjusting for maternal education, duration of breastfeeding and maternal urine phthalates. BPA was detected in 85.3% of the urine samples (median 1.2 ng/ml). Boys of mothers with BPA exposure in the highest tertile had an odds ratio of 3.70 (95% CI 1.34-10.21) of being in the lowest 15th percentile of vocabulary score compared to boys of mothers within the lowest tertile of BPA exposure after adjustment, whereas no association was found in girls. No clear dose-response relationship between maternal BPA and ADHD scores above the 85th percentile was found for either sex. Since early language development is a predictor of future reading skills and educational success, more epidemiological studies assessing BPA exposure and language skills are needed to confirm our findings.

The Effectiveness of a Large-Scale Language and Preliteracy Intervention: The SPELL Randomized Controlled Trial in Denmark.

The present article reports results of a real-world effectiveness trial conducted in Denmark with six thousand four hundred eighty-three 3- to 6-year-olds designed to improve children's language and preliteracy skills. Children in 144 child cares were assigned to a control condition or one of three planned variations of a 20-week storybook-based intervention: a base intervention and two enhanced versions featuring extended professional development for educators or a home-based program for parents. Pre- to posttest comparisons revealed a significant impact of all three interventions for preliteracy skills (= .21-.27) but not language skills (d = .04-.16), with little differentiation among the three variations. Fidelity, indexed by number of lessons delivered, was a significant predictor of most outcomes. Implications for real-world research and practice are considered.

Does sound structure affect word learning? An eye-tracking study of Danish learning toddlers.

Previous research has shown that Danish-learning children lag behind in early lexical acquisition compared with children learning a number of other languages. This delay has been ascribed to the opaque phonetic structure of Danish, which appears to have fewer reliable segmentation cues than other closely related languages. In support of this hypothesis, recent work has shown that the phonetic properties of Danish negatively affect online language processing in young Danish children. In this study, we used eye-tracking to investigate whether the challenges associated with processing Danish also affect how Danish-learning children between 24 and 35 months of age establish and learn novel label-object mappings. The children were presented with a series of novel mappings, either ostensively (one novel object presented alone on the screen) or ambiguously (one novel object presented together with a familiar one), through carrier phrases with different phonetic structures (more vs less opaque). Our results showed two main trends. First, Danish-learning children performed poorly on the task of mapping novel labels onto novel objects. Second, when learning did occur, accuracy was affected by the phonetic opacity of the speech stimuli. We suggest that this finding results from the interplay of a perceptually challenging speech input and a slower onset of early vocabulary experience, which in turn may delay the onset of word learning skills in Danish-learning children.

Self-reported parental vocabulary input frequency for young children.

Vocabulary input frequency influences age of acquisition, and is also an essential control for investigating the influence of other factors. We propose a new method of frequency estimation, self-report. 918 Danish-speaking parents of 12-36-month-old children estimated their frequency of use of 725 words. Self-report was substantially correlated with both language sample based frequencies (0.67) and frequencies of a large written corpus of Danish (0.58). Correlations within vocabulary categories between frequency and age of acquisition, restricted to words occurring in the language samples, were comparable for the two estimates. Overall, self-report based frequency estimates appear to have a promising degree of validity, which reflects their greatest strength, independence of the situation.

Thyroid autoimmunity in euthyroid pregnant women is associated with slower productive language acquisition: the Odense child cohort study.

Objective: Maternal thyroid autoimmunity and thyroid function in early pregnancy may impact fetal neurodevelopment. We aimed to investigate how thyroid autoimmunity and thyroid function in early pregnancy were associated with language acquisition in offspring at 12-36 months of age. Methods: This study was embedded in the prospective Odense child cohort. Mother-child dyads were excluded in case of maternal intake of thyroid medication during pregnancy. The parents completed MacArthur-Bates Communicative Development Inventories (MB-CDI) every third month to assess their offspring's productive vocabulary. All completed reports for each child were included in the analyses. Logistic growth curve models evaluated associations between MB-CDI scores and levels of maternal thyroid peroxidase antibodies (TPOAb), free thyroxine (FT4), and thyrotropin, respectively, measured in early pregnancy (median gestational week 12). All models were stratified by offspring sex and adjusted for maternal age, education, pre-pregnancy body mass index, parity, breastfeeding, and offspring age. Results: The study included 735 mother-child dyads. Children born to mothers with TPOAb ≥11 kIU/L, opposed to TPOAb <11 kIU/L, had a lower probability of producing words at age 18-36 months for girls (OR = 0.78, P < 0.001) and 33-36 months for boys (OR = 0.83, P < 0.001). The probability of producing words was higher in girls at 30-36 months of age with low-normal maternal FT4 vs high-normal FT4 (OR = 0.60, P < 0.001), and a similar trend was seen in boys. Results were ambiguous for thyrotropin. Conclusion: In women without known thyroid disease, TPOAb positivity in early pregnancy was negatively associated with productive vocabulary acquisition in girls and boys. This association was not mediated by a decreased thyroid function, as low-normal maternal FT4, unexpectedly, indicated better vocabulary acquisition. Our results support that maternal thyroid autoimmunity per se may affect fetal neurodevelopment.

The use of the Internet in collecting CDI data--an example from Norway.

This article presents the methodology used in a population-based study of early communicative development in Norwegian children using an adaptation of the MacArthur-Bates communicative development inventories (CDI), comprising approximately 6500 children aged between 0.8 and 3.0. To our knowledge, this is the first CDI study collecting data via the Internet. After a short description of the procedures used in adapting the CDI to Norwegian and the selection of participants, we discuss the advantages and potential pitfalls of using web-based forms as a method of data collection. We found that use of web-based forms was far less time-consuming, and therefore also far less expensive than the traditional paper-based forms. The risk of coding errors was virtually eliminated with this method. We conclude that in a society with high access to the Internet, this is a method well worth pursuing.

Relative heritage language and majority language use before school start explains variance in 2nd grade majority language but not reading skills.

The present study examined whether parents' and bilingual children's own relative use of the heritage language vs. the majority language in the homes of bilingual children in Denmark before school start explains variance in 2nd grade majority language skills and reading skills. The study included two groups of children: the Mixed bilinguals group (defined by having a native Danish and a nonnative parent, N = 376) and the Heritage bilinguals group (defined by having parents who were both speakers of a Heritage language, N = 276). Four-stage hierarchical regression analyses showed that, after accounting for type of bilingualism, socioeconomic status (SES) and home literacy environment quality, relative use of the heritage vs. the majority language explained variance in 2nd grade Danish language comprehension scores, but did not explain variance in two reading scores, namely decoding and reading comprehension. In addition, a home literacy factor denoting book exposure (number of books, frequency of reading, library visits, and age of beginning shared book reading) was a significant predictor of both 2nd grade language and reading outcomes, whereas SES became a nonsignificant predictor when adding home literacy and language use predictors. We interpret the results to mean that parents' and the child's own relative use of the heritage language vs. the majority language before school start does not influence bilingual children's early reading skills, whereas a supportive early home literacy environment is a positive predictor of reading skills independently of SES and parental majority language use and skill.

Maternal cortisol levels in third trimester and early language development: A study of 1093 mother-child pairs from the Odense Child Cohort.

Language development during early childhood is considered an important marker of fetal neurodevelopment. Prenatal cortisol exposure plays a critical role in maturation of the fetal brain; however, the effect on offspring language development needs further investigation. In this prospective observational study we aimed to evaluate the association between maternal third trimester cortisol and early longitudinal offspring language development in the Odense Child Cohort (OCC) and to test whether there were sex differences in the association. The study cohort included 1093 mother-child dyads (570 boys and 523 girls). Fasting morning serum (s-) cortisol was collected from third trimester (gestational week 26-28) pregnant women and measured by liquid chromatography-tandem mass spectrometry. Offspring receptive and productive vocabulary assessments by MacArthur-Bates Communicative Development Inventories parent reports were completed every third month from children age 12-37 months. Levels of cortisol were higher in women carrying a girl (858 ± 214 nmol/L) than in women carrying a boy (820 ± 222 nmol/L). Higher third trimester maternal cortisol levels showed a positive association with development of productive vocabulary in boys at age 12-21 months (OR = 1.23, SE = 0.07, p = .005) and age 22-37 months (OR = 1.09, SE = 0.06, p = .967). Higher maternal cortisol levels in the third trimester were positively associated with receptive vocabulary in girls at 12-21 months of age (OR = 1.16, SE = 0.05, p = .002). Maternal third trimester s-cortisol levels were positively associated with early language development in children at age 12-37 months.

Direct and indirect effects from parenting self-efficacy and parenting practices to social-emotional adjustment in 3- to 5-year-old children.

Parenting self-efficacy has been tied to myriad child outcomes during middle childhood and adolescence, directly and indirectly through parenting practices. The present study examines contemporaneous associations between parenting self-efficacy, parenting practices, and child outcomes during the preschool years in a community sample of 1455 Danish parents (76.7 % mothers) of 3-5-year-old children (49 % girls). Parents (M = 39.2 years old) completed a survey describing parenting self-efficacy and three facets of parenting practices: inductive reasoning, psychological control, and instrumental reward. Parents also described child adjustment in four domains: prosocial behavior, hyperactivity, conduct problems, and emotional problems. Results revealed direct concurrent associations between parenting self-efficacy and each child outcome, with greater efficacy tied to more prosocial behavior and less hyperactivity, conduct problems, and emotional problems. Parent psychological control mediated associations from parenting self-efficacy to child hyperactivity, conduct problems, and emotional problems. Inductive reasoning mediated associations from parenting self-efficacy to child prosocial behavior. Consistent with previous findings from older children, parental use of psychological control had debilitating consequences for preschool children. Inductive reasoning, in contrast, appeared to promote positive development.

Estimating measurement error in child language assessments administered by daycare educators in large scale intervention studies.

Measurement error is a ubiquitous element of social science studies. In large-scale effectiveness intervention studies on child language, administration of the assessment of language and preliteracy outcomes by speech and language pathologists is costly in money and human resources. Alternatively, daycare educators can administer the assessment, which preserves considerable resources but may increase the measurement error. Using data from two nationwide child language intervention studies in Denmark, this article evaluates daycare educators' measurement error when administering a test of language and preliteracy skills of 3 to 5 year old children that in part is used in a national screening program. Since children were randomly assigned to educators, hierarchical linear models can estimate the amount of additional measurement error caused by educators' language assessments. The result shows that the amount of additional measurement error varied between different language subscales, ranging from 4% to 19%, which can be compensated for by increasing the sample size by the latter percentage. The benefits and risks of having daycare educators administer language assessments are discussed.

Sustained effects of an early childhood language and literacy intervention through second grade: Longitudinal findings of the SPELL trial in Denmark.

Predictive relations between language and literacy skills during the preschool years and children's future reading achievement are well-documented, leading to development and evaluation of preschool interventions targeting early skill development. Although educational researchers have developed and found some positive short- and mid-term effects of language and literacy intervention supplements implemented in early childhood education (ECE) settings, fade-out is a concern. Most studies have targeted children experiencing risk, rather than a more representative sample. Additionally, there are very few studies of long-term intervention effects, and heterogeneity of long-term effects has not been well described. In the present study, we build on initial reports of one of the largest studies of a language and literacy intervention supplement, the SPELL randomized controlled trial implemented as part of the universal ECE system in Denmark. SPELL was delivered to an unselected sample of children at 3-5 years of age (n = 7,076). Results of the base intervention (SPELL) and two enhanced versions featuring extended professional development for teachers (SPELL+PD) or an add-on home-based program for parents (SPELL+HOME) showed short-term effects for literacy outcomes for all children for all SPELL conditions compared to business as usual (BAU). In this follow-up study, we utilized follow-up assessments of 2,700 SPELL 4-5-year-old participants with national reading tests in second grade. The main analyses based on the whole sample showed no significant differences in reading scores in second grade for those in any of the three SPELL conditions relative to the BAU condition. However, moderation analyses demonstrated heterogeneity in intervention effects with children whose mothers had low-mid education showing sustained and mostly large-sized effects. Other risk factors, including income and immigrant background, and condition interacted with at least one outcome variables. These findings suggest that at-risk children in some cases derive long-term benefits from early language and literacy intervention enhancing learning opportunities in ECE settings.

Prenatal exposure to pyrethroid and organophosphate insecticides and language development at age 20-36 months among children in the Odense Child Cohort.

BACKGROUND: Prenatal exposure to organophosphate and pyrethroid insecticides has been associated with impaired neurodevelopment. Few longitudinal studies have investigated associations with early language development in populations with mainly low dietary exposure. OBJECTIVE: To investigate associations between biomarkers of maternal gestational exposure to organophosphate and pyrethroid insecticides and the child's language development at age 20-36 months in the prospective Odense Child Cohort. METHODS: Metabolites of organophosphate and pyrethroid insecticides were measured in maternal urine samples collected at gestational week 28. Language development was assessed among 755 singletons at age 20-36 months using the Vocabulary and Complexity scores of the MacArthur-Bates Communicative Development Inventories, standardized into age and sex specific percentile scores according to a Danish reference study. Multiple logistic regression models were used to estimate the odds of scoring below the 15th percentile scores in relation to maternal urinary insecticide metabolite concentrations after adjustment for confounders. RESULTS: The generic pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA) and the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCPY) were detectable in more than 90% of the urine samples analyzed. Likewise, 82.2% had detectable concentrations of diethyl phosphates (DE) and 58.4% of dimethyl phosphates (DM), both of which are common metabolites of organophosphate insecticides. None of the metabolites was associated with higher odds of delayed results below the 15th percentile language scores. In contrast, reduced probability for scoring below the 15th percentile Vocabulary score was seen for the highest tertile of 3-PBA in boys and for the upper tertile of TCPY and DE in girls. CONCLUSION: In this prospective cohort, with predominantly dietary insecticide exposure, we found no evidence that gestational exposure to organophosphate or pyrethroid insecticides adversely affected early language development in the children. The observed indication of a positive effect of insecticides on language development may be explained by residual and unmeasured confounding from socioeconomic factors and dietary habits. Follow-up of these children should include assessment of more complex cognitive functions in later childhood, as well as associations with their own postnatal insecticide exposure.

CLEX: a cross-linguistic lexical norms database*.

Parent report has proven a valid and cost-effective means of evaluating early child language. Norming datasets for these instruments, which provide the basis for standardized comparisons of individual children to a population, can also be used to derive norms for the acquisition of individual words in production and comprehension and also early gestures and symbolic actions. These lexical norms have a wide range of uses in basic research, assessment and intervention. In addition, cross-linguistic comparisons of lexical development are greatly facilitated by the availability of norms from diverse languages. This report describes the development of CLEX, a new web-based cross-linguistic database for lexical data from adaptations of the MacArthur-Bates Communicative Development Inventories. CLEX provides tools for a range of analyses within and across languages. It is designed to incorporate additional language datasets easily, and to permit users to define mappings between lexical items in pairs of languages for more specific cross-linguistic comparisons.

Construction of a Danish CDI short form for language screening at the age of 36 months: methodological considerations and results.

Several research groups have previously constructed short forms of the MacArthur-Bates Communicative Development Inventories (CDI) for different languages. We consider the specific aim of constructing such a short form to be used for language screening in a specific age group. We present a novel strategy for the construction, which is applicable if results from a population-based study using the CDI long form are available for this age group. The basic approach is to select items in a manner implying a left-skewed distribution of the summary score and hence a reliable discrimination among children in the lower end of the distribution despite the measurement error of the instrument. We report on the application of the strategy in constructing a Danish CDI short form and present some results illustrating the validity of the short form. Finally we discuss the choice of the most appropriate age for language screening based on a vocabulary score.

Infants' and Toddlers' Language, Math and Socio-Emotional Development: Evidence for Reciprocal Relations and Differential Gender and Age Effects.

Toddlerhood is characterized by rapid development in several domains, such as language, socio-emotional behavior and emerging math skills all of which are important precursors of school readiness. However, little is known about how these skills develop over time and how they may be interrelated. The current study investigates young children's development at two time points, with about 7 months in between, assessing their language, socio-emotional and math language and numeracy skills with teacher ratings. The sample includes 577 children from 18 until 36 months of age of 86 childcare classrooms. The results of the autoregressive path analyses showed moderate to strong stability of language, socio-emotional and math language and numeracy skills, although the magnitude of associations was smaller for the latter. The cross-lagged path analyses highlighted the importance of language and socio-emotional skills for development in the other domains. Differential relations were found for the autoregressive and cross-lagged paths depending on gender and age. Language skills appeared a stronger predictor of boys' socio-emotional and math language and numeracy skill development compared to girls. Girls' socio-emotional skills predicted growth in math. For boys, socio-emotional and math language and numeracy skills appeared to be unrelated. Language skills showed stronger relations with the development of math language and numeracy skills for younger children as compared to older children. Also, for older children math language and numeracy skills negatively predicted growth in their socio-emotional skills. The findings provide more insights in how language, math language and numeracy skills and socio-emotional skills co-develop in the early years and as such have important implications for interventions aimed to support children's development.

Parents' Growth Mindsets and Home-Learning Activities: A Cross-Cultural Comparison of Danish and US Parents.

Mindset is a term commonly used to represent an individual's beliefs about the role of ability and effort in learning. In this study, we assessed parental mindset-ability mindset and effort mindset-for 497 parents in two countries (United States and Denmark), all of whom had at least one child between 3 and 5 years of age. Of primary interest was assessing the relations between parental mindset and home-learning activities of four types: family learning activities, learning extensions, parental time investment, and parental school involvement. Findings showed that parents in the United States and Denmark held similar ability and effort mindsets, but differed significantly in home-learning activities, with US parents providing significantly more family learning activities, learning extensions, and parental time investment than Danish parents, although the latter had significantly higher levels of school investment. Furthermore, findings showed that parents' effort mindset was a significant predictor of family learning activities and parental time investment and that country moderated the relations between effort mindset and parental time investment. For US parents, higher levels of effort mindset were associated with higher levels of parental time investment, but this was not the case for Danish parents. We call for experimental work to determine the causal relations between parental mindset and home-learning activities, and rigorous cross-cultural research to explore the universality of parental mindset in distinctive cultural settings.

When Too Many Vowels Impede Language Processing: An Eye-Tracking Study of Danish-Learning Children.

Research has suggested that Danish-learning children lag behind in early language acquisition. The phenomenon has been attributed to the opaque phonetic structure of Danish, which features an unusually large number of non-consonantal sounds (i.e., vowels and semivowels/glides). The large number of vocalic sounds in speech is thought to provide fewer cues to word segmentation and to make language processing harder, thus hindering the acquisition process. In this study, we explored whether the presence of vocalic sounds at word boundaries impedes real-time speech processing in 24-month-old Danish-learning children, compared to word boundaries that are marked by consonantal sounds. Using eye-tracking, we tested children's real-time comprehension of known consonant-initial and vowel-initial words when presented in either a consonant-final carrier phrase or in a vowel-final carrier phrase, thus resulting in the four boundary types C#C, C#V, V#C, and V#V. Our results showed that the presence of vocalic sounds around a word boundary-especially before-impedes processing of Danish child-directed sentences.

Evaluation of methods used to assess language development of 3-4-year-old Danish children.

This paper targets assessment instruments used by speech-language therapists in Denmark for monolingual 3-4-year-old children. The paper is based on two studies. In the first study 29 assessment instruments were compared with respect to language constructs that were covered by the instruments. In the second study 26 assessment instruments were evaluated based on international guide-lines. The main finding from the first study revealed a lack of appropriate assessment instruments targeting relevant language constructs in assessment instruments for this age-group. The most important result from the second study revealed a massive lack of information and documentation, which probably in many cases points to a lack of use of established, scientific principles.