Prenatal and early childhood predictors of intelligence quotient (IQ) in 7-year-old Danish children from the Odense Child Cohort

Beck, Iben Have; Bilenberg, Niels; Davidsen, Kirstine Agnete; Rasmussen, Anne; Boye, Henriette; Jensen, Tina Kold

doi:10.1177/14034948221077463

Cited by 11 publications

(8 citation statements)

References 41 publications

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“…113 Another limitation was the inappropriate adjustment for mediator variables. The failure to consider a causal diagram in the analysis led some studies to inadvertently adjust for schooling 1,18,[29][30][31][32] or previous intelligence tests. 1,30 Since we are interested in the total effect of head circumference, this approach could cause bias toward the null.…”

Section: Discussionmentioning

confidence: 99%

Head circumference and intelligence, schooling, employment, and income: a systematic review

Freire

Slater

Silva

et al. 2023

Preprint

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Background No consensus exists about the role of head circumference in identifying children at risk of suboptimal development. The objective of this study was to evaluate the association between head circumference and intelligence, schooling, employment, and income. The review 1) summarizes the overall evidence and 2) restricts the evidence to a subset of articles that met minimum quality criteria. Methods PubMed, Web of Science, PsycINFO, LILACS, CINAHL, WHO Institutional Repository for Information Sharing and UNICEF Innocenti were searched to identify published studies. Cohort, case-control or cross-sectional studies which evaluated the associations of interest in the general population, premature babies, babies with low birth weight or small for gestational age were included. Two reviewers independently performed study selection, data extraction and quality assessments. Results Of 2521 records identified, 115 were included and 21 met the minimum quality criteria. We identidied large heterogeneity and inconsistency in the effect measures and data reported across studies. Despite the relatively large number of included articles, more than 80% presented serious limitations such as severe selection bias and lack of adjustment for confounding. Considering the subset of articles which met the minimum quality criteria, 12 of 16 articles showed positive association between head circumference and intelligence in the general population. However, in premature babies, 2 of 3 articles showed no clear effect. Head circumference was positively associated with academic performance in all investigated samples (5 of 5 articles). No article which evaluated educational attainment and employment met the minimum quality criteria, but the association between head circumference and these outcomes seems to be positive. Conclusions Larger head circumferences in the first 1000 days is positively associated with higher levels of intelligence and academic performance in the general population, but there is evidence of non-linearity in those associations. Identifying a group of children in higher risk for worse outcomes by a simple and inexpensive tool could provide an opportunity to mitigate these negative effects. Further research is needed for a deeper understanding of the whole distribution of head circumference and its effect in premature babies. Authors should consider the non-linearity of the association in the data analysis. Systematic Review Registration: Association between head circumference and intelligence, educational attainment, employment, and income: A systematic review, CRD42021289998, https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021289998

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Section: Discussionmentioning

confidence: 99%

Head circumference and intelligence, schooling, employment, and income: a systematic review

Freire

Slater

Silva

et al. 2023

Preprint

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“…Due to study design limitations, we did not include a term-born control group. However, in the 'Odense Child Cohort' [31], children had a mean IQ score at 7 years of 99.1 (SD 11.9) on the WISC-V [32], and even though our study cohort was defined by the absence of major neonatal morbidities, we expected IQ scores to be below average due to prematurity [1]. As our entire cohort was examined by one psychologist, we expect the comparison between the groups to be unaffected by the rather high mean score on the WISC-IV.…”

Section: Discussionmentioning

confidence: 99%

IQ Was Not Improved by Post-Discharge Fortification of Breastmilk in Very Preterm Infants

et al. 2022

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(1) Very preterm infants are at increased risk of cognitive deficits, motor impairments, and behavioural problems. Studies have tied insufficient nutrition and growth to an increased risk of neurodevelopmental impairment; (2) Methods: Follow-up study on cognitive and neuropsychological development at 6 years corrected age (CA) in 214 very preterm infants, including 141 breastfed infants randomised to mother’s own milk (MOM) with (F-MOM) or without (U-MOM) fortification and 73 infants fed a preterm formula (PF-group), from shortly before discharge to 4 months CA. Infants with serious congenital anomalies or major neonatal morbidities were excluded prior to intervention. The Wechsler Intelligence Scale for Children IV was used for cognitive testing, and the children’s parents completed the Five to Fifteen Questionnaire (FTF); (3) Results: Post-discharge fortification of MOM did not improve either full-scale intelligence quotient (FSIQ) with a median of 104 vs. 105.5 (p = 0.29), subdomain scores, or any domain score on the FTF questionnaire. Compared to the PF group, the MOM group had significantly better verbal comprehension score with a median of 110 vs. 106 (p = 0.03) and significantly better motor skills scores on the FTF questionnaire (p = 0.01); (4) Conclusions: The study supports breastfeeding without fortification as post-discharge nutrition in very preterm infants, and it seems superior to preterm formula.

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“…The present research is based on individual data concerning the assessment of child neurodevelopment and the measurement of OPFR exposure in the urine of the Odense Child Cohort (OCC) in Denmark (Odense University Hospital in Denmark) [49,50] and the PCB cohort in Slovakia (Department of Environmental Medicine, Faculty of Public Health, Slovak Medical University) [51,52], which have participated in the HBM4EU Aligned Studies. A detailed description of the sampling methods for inclusion of participants and data harmonization in the HBM4EU Aligned Studies is reported in [45].…”

Section: Data Sourcementioning

confidence: 99%

Cognitive Performance and Exposure to Organophosphate Flame Retardants in Children: Evidence from a Cross-Sectional Analysis of Two European Mother–Child Cohorts

Rosolen,

Giordani,

Mariuz

et al. 2023

Toxics

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The knowledge of the effects of organophosphate flame retardants on children’s neurodevelopment is limited. The purpose of the present research is to evaluate the association between exposure to organophosphate flame retardants and children’s neurodevelopment in two European cohorts involved in the Human Biomonitoring Initiative Aligned Studies. The participants were school-aged children belonging to the Odense Child Cohort (Denmark) and the PCB cohort (Slovakia). In each cohort, the children’s neurodevelopment was assessed through the Full-Scale Intelligence Quotient score of the Wechsler Intelligence Scale for Children, using two different editions. The children’s urine samples, collected at one point in time, were analyzed for several metabolites of organophosphate flame retardants. The association between neurodevelopment and each organophosphate flame retardant metabolite was explored by applying separate multiple linear regressions based on the approach of MM-estimation in each cohort. In the Danish cohort, the mean ± standard deviation for the neurodevelopment score was 98 ± 12; the geometric mean (95% confidence interval (95% CI)) of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) standardized by creatinine (crt) was 0.52 µg/g crt (95% CI = 0.49; 0.60), while that of diphenyl phosphate (DPHP) standardized by crt was 1.44 µg/g crt (95% CI = 1.31; 1.58). The neurodevelopment score showed a small, negative, statistically imprecise trend with BDCIPP standardized by crt (β = −1.30; 95%CI = −2.72; 0.11; p-value = 0.07) and no clear association with DPHP standardized by crt (β = −0.98; 95%CI = −2.96; 0.99; p-value = 0.33). The neurodevelopment score showed a negative trend with BDCIPP (β = −1.42; 95% CI = −2.70; −0.06; p-value = 0.04) and no clear association with DPHP (β = −1.09; 95% CI = −2.87; 0.68; p-value = 0.23). In the Slovakian cohort, the mean ± standard deviation for the neurodevelopment score was 81 ± 15; the geometric mean of BDCIPP standardized by crt was 0.18 µg/g crt (95% CI = 0.16; 0.20), while that of DPHP standardized by crt was 2.24 µg/g crt (95% CI = 2.00; 3.52). The association of the neurodevelopment score with BDCIPP standardized by crt was −0.49 (95%CI = −1.85; 0.87; p-value = 0.48), and with DPHP standardized by crt it was −0.35 (95%CI = −1.90; 1.20; p-value = 0.66). No clear associations were observed between the neurodevelopment score and BDCIPP/DPHP concentrations that were not standardized by crt. No clear associations were observed with bis(1-chloro-2-propyl) phosphate (BCIPP) in either cohort, due to the low detection frequency of this compound. In conclusion, this study provides only limited evidence of an inverse association between neurodevelopment and exposure to BDCIPP and DPHP. The timing of exposure and effect modification of other organophosphate flame retardant metabolites and other substances should be the subject of further investigations that address this scientific hypothesis.

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Prenatal and early childhood predictors of intelligence quotient (IQ) in 7-year-old Danish children from the Odense Child Cohort

Cited by 11 publications

References 41 publications

Head circumference and intelligence, schooling, employment, and income: a systematic review

Head circumference and intelligence, schooling, employment, and income: a systematic review

IQ Was Not Improved by Post-Discharge Fortification of Breastmilk in Very Preterm Infants

Cognitive Performance and Exposure to Organophosphate Flame Retardants in Children: Evidence from a Cross-Sectional Analysis of Two European Mother–Child Cohorts

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