Not Race or Age but Their Interaction Predicts Pre-Adolescents' Inhibitory Control

Income Inequality, Gender Disparities, and Ethnic Differences: Investigating Allostatic Load in American Adults

AIM

To estimate the association between income inequality and allostatic load score (AL) in adults ages 20 years and older, with a particular focus on the differential impacts across racial and gender groups. By examining this association, the study seeks to inform targeted policy interventions to mitigate health disparities exacerbated by economic inequality.

METHODS

Utilizing data from the 1999-2016 National Health and Nutrition Examination Survey (NHANES), we assessed AL through eight biomarkers: systolic blood pressure (mm Hg), diastolic blood pressure (mm Hg), pulse rate (beats/min), body mass index (kg/m2), glycohemoglobin (%), direct HDL cholesterol (mg/dL), total cholesterol (mg/dL), and serum albumin (g/dL). Employing negative binomial regression (NBRG), we estimated incidence rate ratios (IRR) for a sample comprising 7367 men and 7814 women, adjusting for age, race/ethnicity, marital status, education, health insurance, comorbidity, and mental health professional utilization. Gini coefficients (GC) were calculated to assess income inequality among men and women.

RESULTS

Findings revealed that men exhibited a higher poverty-to-income ratio (PIR) compared to women (3.12 vs. 2.86, p < 0.01). Yet, women experienced higher rates of elevated AL (AL > 4) (31.8% vs. 29.0%) and were more adversely affected by income inequality (GC: 0.280 vs. 0.333). NBRG results indicated that high PIR individuals had a lower IRR (0.96; CI:0.92-0.95) compared to their low PIR counterparts, a trend observed in women but not men. High PIR was notably protective among White non-Hispanic (WNH) men and women. Additionally, vigorous and moderate physical activity engagement was associated with lower AL (IRR: 0.89, CI: 0.85-0.93).

CONCLUSION

The study emphasizes the importance of implementing policies that target AL in low-income populations across all racial groups, with a specific focus on Black non-Hispanic (BNH) and Hispanic communities. By prioritizing these groups, policies can more effectively target the nexus of income inequality, health disparities, and allostatic load, contributing to the reduction of health inequities.

Intersectional Effects of Race and Educational Attainment on Memory Function of Middle-Aged and Older Adults With Alzheimer's Disease

BACKGROUND

High educational attainment may protect individuals, particularly middle-aged and older adults, against a wide range of health risks, including memory decline with age; however, this protection is less clear in patients with Alzheimer's disease (AD). In addition, this effect may differ across racial groups. According to the Marginalized-Related Diminished Return (MDR) theory, for example, the protective effect of high educational attainment on mental and physical health shows a weaker protective effect for racial minority groups, particularly Black people compared to White individuals.

OBJECTIVES

This longitudinal study used data of middle-aged and older adults with AD with two aims: first, to test the association between educational attainment and memory, and second, to explore racial differences in this association in the USA.

METHODS

Data came from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study. The total sample was 1673 American middle-aged and older adults. The independent variable was educational attainment measured as years of education. The main outcome was memory operationalized as Rey Auditory Verbal Learning Test (RAVLT) Verbal Forgetting percentage (VF%). Age, gender, and follow-up duration were covariates. Race was the effect modifier. Linear regression model was utilized to analyze the data.

RESULTS

Of all participants, 68 (4.1%) were Black, and the remaining were White, with a mean age of 75 years old. In the pooled sample, educational attainment did not show a significant association with memory, independent of confounders. Educational attainment showed a significant interaction with race on memory, with higher educational attainment having a different effect on memory in White patients compared to Black patients.

CONCLUSION

The effect of higher educational attainment on memory differs for Black patients with AD compared to White patients. To prevent cognitive disparities by race, we need to go beyond racial inequality in access to resources (e.g., education) and minimize diminished returns of educational attainment for racial minorities. To tackle health inequalities, social policies should not be limited to equalizing socioeconomic status but also help minority groups leverage their available resources, such as educational attainment, and secure tangible outcomes.

Cross-Sectional and Longitudinal Relations Among Irritability, Attention-Deficit/Hyperactivity Disorder Symptoms, and Inhibitory Control

OBJECTIVE

Irritability and attention-deficit/hyperactivity disorder (ADHD) symptoms frequently co-occur in youth. Although ADHD has been associated with inhibitory control deficits, the literature on irritability and inhibitory control is mixed. Examining how irritability, ADHD symptoms, and inhibitory control interrelate both cross-sectionally and longitudinally across development could shed light on common and distinct mechanisms of youth psychopathology.

METHOD

We utilized a cross-lagged panel model with data from 2 time points (at ages 10 and 12 years) of the Adolescent Brain and Cognitive Development (ABCD) Study (N = 7,444, or ∼63% of the baseline sample with full data at each time point) to test cross-sectional and longitudinal associations among parent-reported irritability and ADHD symptoms and behaviorally assessed inhibitory control. This was performed separately across discovery and replication subsamples, each n = 3,722.

RESULTS

As expected, irritability and ADHD symptoms exhibited strong cross-sectional and reciprocal cross-lagged associations. Higher ADHD symptoms at age 10 years were associated concurrently with poorer inhibitory control and predicted poorer inhibitory control at age 12. Contrary to predictions, inhibitory control was not significantly associated with irritability cross-sectionally, nor was it predictive of later irritability or ADHD symptoms.

CONCLUSION

These findings highlight strong links between irritability and ADHD. Although inhibitory control deficits were linked to ADHD and predictive of its symptom course, inhibitory control had no significant associations with irritability. Future research should investigate other candidate mechanisms of the co-occurrence of irritability and ADHD symptoms and predictors of their developmental trajectories.

Editorial: Neuropsychological Correlates of Irritability Accompanying Symptoms of Attention-Deficit/Hyperactivity Disorder: Clues and Pitfalls

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders and is characterized by developmentally inappropriate, pervasive, and impairing symptoms of inattention and/or hyperactivity/impulsivity.1 Although not listed among the core symptoms, irritability, reduced tolerance to frustration, and labile mood are considered features associated with ADHD.1,2 Irritability refers to a tendency to get angry quickly and/or easily at a lower threshold of frustration and respond disproportionately to triggers.3 Almost two-thirds of youth with ADHD may display impairing irritability, while rates of ADHD may be elevated among youth with clinically significant irritability.2 Irritability and impulsivity are thought to share neurobiological mechanisms that may overlap with executive and self-regulatory functions such as inhibitory control.3-5 The nature and developmental stability of these associations are still debated. Areas of controversy include the role of emotion regulation problems in positive vs negative emotions for impairment6; relations between those problems and risk-taking behavior, hyperactive-impulsive symptoms, and disruptive behavior problems2-5; and the nature of emotion regulation problems (ie, as core symptoms, as a feature of a variant of ADHD, or as a characteristic of specific comorbidities such as depression).2.

Parental Educational Attainment, the Superior Temporal Cortical Surface Area, and Reading Ability among American Children: A Test of Marginalization-Related Diminished Returns

BACKGROUND

Recent studies have shown that parental educational attainment is associated with a larger superior temporal cortical surface area associated with higher reading ability in children. Simultaneously, the marginalization-related diminished returns (MDRs) framework suggests that, due to structural racism and social stratification, returns of parental education are smaller for black and other racial/ethnic minority children compared to their white counterparts.

PURPOSE

This study used a large national sample of 9-10-year-old American children to investigate associations between parental educational attainment, the right and left superior temporal cortical surface area, and reading ability across diverse racial/ethnic groups.

METHODS

This was a cross-sectional analysis that included 10,817 9-10-year-old children from the Adolescent Brain Cognitive Development (ABCD) study. Parental educational attainment was treated as a five-level categorical variable. Children's right and left superior temporal cortical surface area and reading ability were continuous variables. Race/ethnicity was the moderator. To adjust for the nested nature of the ABCD data, mixed-effects regression models were used to test the associations between parental education, superior temporal cortical surface area, and reading ability overall and by race/ethnicity.

RESULTS

Overall, high parental educational attainment was associated with greater superior temporal cortical surface area and reading ability in children. In the pooled sample, we found statistically significant interactions between race/ethnicity and parental educational attainment on children's right and left superior temporal cortical surface area, suggesting that high parental educational attainment has a smaller boosting effect on children's superior temporal cortical surface area for black than white children. We also found a significant interaction between race and the left superior temporal surface area on reading ability, indicating weaker associations for Alaskan Natives, Native Hawaiians, and Pacific Islanders (AIAN/NHPI) than white children. We also found interactions between race and parental educational attainment on reading ability, indicating more potent effects for black children than white children.

CONCLUSION

While parental educational attainment may improve children's superior temporal cortical surface area, promoting reading ability, this effect may be unequal across racial/ethnic groups. To minimize the racial/ethnic gap in children's brain development and school achievement, we need to address societal barriers that diminish parental educational attainment's marginal returns for middle-class minority families. Social and public policies need to go beyond equal access and address structural and societal barriers that hinder middle-class families of color and their children. Future research should test how racism, social stratification, segregation, and discrimination, which shape the daily lives of non-white individuals, take a toll on children's brains and academic development.

Resting-State Functional Connectivity between Putamen and Salience Network and Childhood Body Mass Index

Introduction: Although the putamen has a significant role in reward-seeking and motivated behaviors, including eating and food-seeking, minorities’ diminished returns (MDRs) suggest that individual-level risk and protective factors have weaker effects for Non-Hispanic Black than Non-Hispanic White individuals. However, limited research is available on the relevance of MDRs in terms of the role of putamen functional connectivity on body mass index (BMI). Purpose: Building on the MDRs framework and conceptualizing race and socioeconomic status (SES) indicators as social constructs, we explored racial and SES differences in the associations between putamen functional connectivity to the salience network and children’s BMI. Methods: For this cross-sectional study, we used functional magnetic resonance imaging (fMRI) data of 6473 9–10-year-old Non-Hispanic Black and Non-Hispanic White children from the Adolescent Brain Cognitive Development (ABCD) study. The primary independent variable was putamen functional connectivity to the salience network, measured by fMRI. The primary outcome was the children’s BMI. Age, sex, neighborhood income, and family structure were the covariates. Race, family structure, parental education, and household income were potential moderators. For data analysis, we used mixed-effect models in the overall sample and by race. Results: Higher right putamen functional connectivity to the salience network was associated with higher BMI in Non-Hispanic White children. The same association was missing for Non-Hispanic Black children. While there was no overall association in the pooled sample, a significant interaction was found, suggesting that the association between right putamen functional connectivity to the salience network and children’s BMI was modified by race. Compared to Non-Hispanic White children, Non-Hispanic Black children showed a weaker association between right putamen functional connectivity to the salience network and BMI. While parental education and household income did not moderate our association of interest, marital status altered the associations between putamen functional connectivity to the salience network and children’s BMI. These patterns were observed for right but not left putamen. Other/Mixed Race children also showed a pattern similar to Non-Hispanic Black children. Conclusions: The association between right putamen functional connectivity to the salience network and children’s BMI may depend on race and marital status but not parental education and household income. While right putamen functional connectivity to the salience network is associated with Non-Hispanic White children’s BMI, Non-Hispanic Black children’ BMI remains high regardless of their putamen functional connectivity to the salience network. This finding is in line with MDRs, which attributes diminished effects of individual-risk and protective factors for Non-Hispanic Black children to racism, stratification, and segregation.