[Article Review] Hidden Harm: Prenatal Phthalate Exposure and Its Impact on Young Brains

Reference

Ghassabian, A., van den Dries, M., Trasande, L., Lamballais, S., Spaan, S., Martinez-Moral, M-P., ... Guxens, M. (2023). Prenatal exposure to common plasticizers: a longitudinal study on phthalates, brain volumetric measures, and IQ in youth. Molecular Psychiatry. https://doi.org/10.1038/s41380-023-02225-6

Review

The paper by Ghassabian et al. (2023) explores the under-researched area of prenatal phthalate exposure, specifically its associations with brain volumetric differences and cognitive development in youth. Drawing from a cohort of 775 mother-child pairs from the Generation R study, the authors leveraged both prenatal maternal urine phthalate levels and subsequent T1-weighted MRI scans of the children at age 10. They aimed to establish correlations between prenatal phthalate exposure and brain volume and to explore if these brain measures mediated an association with IQ levels at age 14.

Findings reveal that higher maternal concentrations of monoethyl phthalate (mEP) during pregnancy were linked to smaller total gray matter volumes in 10-year-old offspring. Notably, these volume differences partially mediated the connection between higher mEP levels and lower child IQ, accounting for 18% of the effect. Gender-specific effects were also reported; in girls, there was an association of higher monoisobutyl phthalate (mIBP) with decreased cerebral white matter volumes, which mediated the link between increased mIBP and reduced IQ. These results underscore the potential neurotoxic effects of phthalates on developing brains, signaling alarm for their ubiquitous presence in consumer products.

While this research paves the way for understanding the neurodevelopmental implications of phthalates, there are aspects to consider for future studies. Primarily, the question arises on potential confounding variables, such as socio-economic status or other environmental factors, that might influence the observed associations. Furthermore, exploring potential mechanisms behind these observed changes would provide deeper insight. Notwithstanding, Ghassabian et al.'s study shines a light on the pressing need to re-evaluate and potentially regulate the use of phthalates in consumer products.

[Article Review] Maternal Milk Feeding in Preterm Infants: The Key to Better Neurodevelopmental Outcomes?

Reference

Belfort, M. B., Knight, E., Chandarana, S., Ikem, E., Gould, J. F., Collins, C. T., Makrides, M., Gibson, R. A., Anderson, P. J., Simmer, K., Tiemeier, H., & Rumbold, A. (2022). Associations of Maternal Milk Feeding With Neurodevelopmental Outcomes at 7 Years of Age in Former Preterm Infants. JAMA Network Open, 5(7), e2221608. https://doi.org/10.1001/jamanetworkopen.2022.21608

Review

The study by Belfort et al. (2022) examined the association between maternal milk feeding and neurodevelopmental outcomes at 7 years of age in preterm infants born at less than 33 weeks of gestation. The prospective cohort study involved 586 infants from five Australian perinatal centers who were enrolled in the Docosahexaenoic Acid for Improvement of Neurodevelopmental Outcomes study between January 1, 2001, and December 31, 2005.

The researchers measured maternal milk intake, including mean volume (milliliters per kilogram per day) during neonatal hospitalization and total duration (in months), as well as neurodevelopmental outcomes at 7 years of age. The outcomes assessed were IQ, academic achievement, ADHD symptoms, executive function, and behavior.

The results showed that higher maternal milk intake during neonatal hospitalization was associated with better performance IQ, reading, and math scores, and fewer ADHD symptoms. Longer duration of maternal milk intake was associated with higher reading, spelling, and math scores. Interestingly, the study found that maternal milk feeding was not associated with improved full-scale IQ, verbal IQ, executive function, or behavior. Most associations were stronger among infants born at lower gestational ages, particularly less than 30 weeks.

In conclusion, the findings of Belfort et al. (2022) suggest that maternal milk feeding during neonatal hospitalization and after discharge might be associated with better school-age performance IQ and academic achievement, and with a reduction in ADHD symptoms, particularly among infants born at less than 30 weeks gestation.

[Article Review] The Gut-Brain Connection: Bacteroidetes-Dominant Microbiome Linked to Enhanced Neurodevelopment in Infancy

Reference

Tamana, S. K., Tun, H. M., Konya, T., Chari, R. S., Field, C. J., Guttman, D. S., Becker, A. B., Moraes, T. J., Turvey, S. E., Subbarao, P., Sears, M. R., Pei, J., Scott, J. A., Mandhane, P. J., & Kozyrskyj, A. L. (2021). Bacteroides-dominant gut microbiome of late infancy is associated with enhanced neurodevelopment. Gut Microbes, 13(1), 1930875. https://doi.org/10.1080/19490976.2021.1930875

Review

The article by Tamana et al. (2021) investigates the association between gut microbiota and early neurodevelopment in infants. The authors analyzed data from 405 infants from the Canadian Healthy Infant Longitudinal Development (CHILD) Cohort Study, using the Bayley Scale of Infant Development (BSID-III) to assess neurodevelopmental outcomes at 1 and 2 years of age. Fecal samples were collected at a mean age of 4 and 12 months for microbiota profiling using 16S rRNA gene sequencing.

The study identified three infant groups based on the relative abundance of gut microbiota at 12 months: Proteobacteria-dominant, Firmicutes-dominant, and Bacteroidetes-dominant clusters. The Bacteroidetes-dominant cluster demonstrated a significant positive association with cognitive, language, and motor development scores at age 2, particularly among male infants. The genus Bacteroides abundance in gut microbiota was positively correlated with cognitive and language scores at age 2. The study found no associations between 4-month microbiota clusters and BSID-II scores.

Tamana et al. (2021) suggest that Bacteroidetes-dominant gut microbiota in late infancy is associated with better neurodevelopment, particularly in males. Enhanced sphingolipid synthesis and metabolism, as well as antagonism or competition between Bacteroides and Streptococcus, were characteristic of Bacteroidetes-dominant gut microbiota. This study contributes valuable insights into the gut-brain connection and the potential impact of gut microbiota on early neurodevelopment.

[Article Review] Unlocking Potential: How Education Can Improve Intelligence

Reference

Ritchie, S. J., & Tucker-Drob, E. M. (2018). How Much Does Education Improve Intelligence? A Meta-Analysis. Psychological Science, 29(8), 1358-1369. https://doi.org/10.1177/0956797618774253

Review

In this article, Ritchie and Tucker-Drob (2018) explore the relationship between education and intelligence, specifically whether more education leads to increased intelligence. The authors conducted a meta-analysis of 142 effect sizes from 42 data sets, involving over 600,000 participants, using quasi-experimental methods including controlled associations, instrumental variables, and regression-discontinuity designs. The results reveal a consistent, positive effect of education on cognitive abilities, with an increase of 1 to 5 IQ points for each additional year of education.

The authors' robust analysis further highlights the durability of the observed effects, as they persist across various life stages and all broad categories of cognitive ability. This finding is significant, as it suggests that education is a consistent and reliable method for increasing intelligence. By using various research designs, Ritchie and Tucker-Drob (2018) strengthen the validity of their findings, making a compelling case for the importance of continued education in promoting cognitive development.

Overall, the study by Ritchie and Tucker-Drob (2018) offers valuable insight into the impact of education on intelligence, and its findings have important implications for policymakers and educators. The results underscore the significance of investing in education to promote cognitive growth, which can contribute to individual and societal success. This study lays a strong foundation for future research exploring the specific mechanisms through which education may enhance intelligence and cognitive abilities.