[Article Review] White Matter Microstructure and Cognitive Performance: Insights from a Meta-Analysis in Schizophrenia

Reference

Holleran, L., Kelly, S., Alloza, C., Agartz, I., Andreassen, O. A., Arango, C., ... & Donohoe, G. (2020). The Relationship Between White Matter Microstructure and General Cognitive Ability in Patients With Schizophrenia and Healthy Participants in the ENIGMA Consortium. American Journal of Psychiatry, 177(6), 537-547. https://doi.org/10.1176/appi.ajp.2019.19030225

Review

Holleran et al. (2020) conducted a meta-analysis to explore the relationship between white matter microstructure and cognitive performance in patients with schizophrenia and healthy participants using data from the ENIGMA Consortium. The study included 760 patients with schizophrenia and 957 healthy participants from 11 sites. The authors used principal component analysis to calculate a global fractional anisotropy component and a fractional anisotropy component for six long association tracts. The results showed that higher fractional anisotropy was associated with higher cognitive ability. The study provides robust evidence that cognitive ability is associated with global structural connectivity, independent of diagnosis.

The authors noted that schizophrenia is associated with widespread white matter microstructural abnormalities, but the functional effects of these abnormalities remain unclear. This study contributes to the current understanding of the relationship between white matter microstructure and cognitive performance in patients with schizophrenia and healthy participants. The meta-analysis included a large sample size from multiple sites, and a common analysis pipeline was used, which enhances the validity of the results. The findings suggest that there is a more general, rather than disease-specific, pattern of association between fractional anisotropy and cognitive ability.

Overall, the study by Holleran et al. (2020) provides valuable insights into the relationship between white matter microstructure and cognitive performance in patients with schizophrenia and healthy participants. The findings suggest that cognitive ability is associated with global structural connectivity, and the association is independent of diagnosis. The study highlights the importance of investigating the functional effects of white matter microstructural abnormalities in schizophrenia to improve social and functional outcomes in patients.

[Article Review] The Burden of Early-life Chemical Exposure on Neurodevelopmental Disabilities in the US

Reference

Gaylord, A., Osborne, G., Ghassabian, A., Malits, J., Attina, T., & Trasande, L. (2020). Trends in neurodevelopmental disability burden due to early life chemical exposure in the USA from 2001 to 2016: A population-based disease burden and cost analysis. Molecular and Cellular Endocrinology, 502, 110666. https://doi.org/10.1016/j.mce.2019.110666

Review

The study by Gaylord et al. (2020) aimed to quantify the burden of neurodevelopmental disability and the economic costs associated with early-life exposure to endocrine-disrupting chemicals (EDCs) in the United States from 2001 to 2016. Using data from the National Health and Nutrition Examination Surveys, the authors estimated the intellectual disability (ID) burden attributable to in-utero exposure to polybrominated diphenyl ethers (PBDEs), organophosphates, methylmercury, and early-life exposure to lead. They also calculated the economic costs of the IQ point lost and cases of intellectual disability. The results showed that PBDE exposure was the most significant contributor to the ID burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability. Lead, organophosphates, and methylmercury were the other contributors. Although most of the trends showed improvement in children's neurodevelopmental health, they also indicated the use of potentially harmful chemical substitutions for those being phased out.

The findings of this study have significant implications for public health policies and regulations regarding the use and exposure of EDCs. The authors suggest that current regulations on EDCs should be strengthened to reduce the burden of neurodevelopmental disabilities and the associated economic costs. The study also highlights the need for continued monitoring of trends in early-life chemical exposure to ensure that the use of potentially harmful chemicals is adequately controlled. Limitations of the study include the use of cross-sectional data and the lack of information on exposure to other chemicals known to cause neurotoxicity. However, the study provides valuable insights into the burden of neurodevelopmental disabilities and the costs associated with exposure to EDCs in the US.

[Article Review] Maternal Obesity and Child Cognitive Outcomes: A Sex-Specific Relationship

Reference

Widen, E. M., Nichols, A. R., Kahn, L. G., Factor-Litvak, P., Insel, B. J., Hoepner, L., Dube, S. M., Rauh, V., Perera, F., & Rundle, A. (2019). Prepregnancy obesity is associated with cognitive outcomes in boys in a low-income, multiethnic birth cohort. BMC Pediatrics, 19, 507. https://doi.org/10.1186/s12887-019-1853-4

Article

Widen et al. (2019) conducted a study to investigate whether maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) are associated with cognitive outcomes in 7-year-old children from a low-income, multiethnic birth cohort. The authors hypothesized that maternal prepregnancy obesity and high GWG would have negative effects on child neurodevelopment, particularly among boys. Data from 368 African American and Dominican women and their children were analyzed using linear regression models. The results revealed that prepregnancy overweight and obesity were associated with lower full-scale IQ scores among boys but not girls. GWG was not associated with cognitive outcomes in either sex. These findings suggest that maternal prepregnancy obesity may have sex-specific effects on child neurodevelopment, which should be taken into consideration for public health interventions aimed at improving cognitive outcomes.

One strength of this study is its prospective design, which allowed for the measurement of maternal BMI and GWG during pregnancy and subsequent assessment of child neurodevelopment. Additionally, the study sample consisted of a diverse population of low-income women and their children, which increases the generalizability of the findings. However, the study also has some limitations. For instance, the authors did not examine the potential mechanisms underlying the association between maternal obesity and child neurodevelopment. Future studies should investigate potential biological and environmental pathways that may explain this relationship.

Overall, this study provides evidence for a sex-specific association between maternal prepregnancy obesity and child cognitive outcomes among low-income populations. These findings have important implications for public health interventions aimed at reducing the prevalence of maternal obesity and improving cognitive outcomes in children.