Risk of dementia due to Co-exposure to air pollution and neighborhood disadvantage

BACKGROUND

Co-exposure to air pollution and neighborhood disadvantage may influence cognition decline. We tested these associations in the context of dementia risk.

METHODS

We leveraged a cohort of adults ≥65 years (n = 5397) enrolled from 2011 to 2018 in the National Health and Aging Trends Study (NHATS). Particulate matter (PM) ≤ 10 μm in diameter, PM ≤ 2.5 μm in diameter, carbon monoxide, nitric oxide, and nitrogen dioxide - and neighborhood disadvantage were tested for joint associations with dementia risk. Pollutant concentrations at the 2010 census tract level were assigned using the US Environmental Protection Agency's Community Multiscale Air Quality Modeling System. Neighborhood disadvantage was defined using the tract Social Deprivation Index (SDI). Dementia was determined through self- or proxy-report or scores indicative of "probable dementia" according to NHATS screening tools. Joint effects of air pollutants and SDI were tested using quantile g-computation Cox proportional hazards models. We also stratified joint air pollution effects across SDI tertiles. Analyses adjusted for age at enrollment, sex, education, partner status, urbanicity, income, race and ethnicity, years at residence, census segregation, and census region.

RESULTS

SDI score (aHR = 1.08; 95% CI 0.96, 1.22), joint air pollution (aHR = 1.03, 95% CI 0.92, 1.16) and joint SDI with air pollution (aHR = 1.04, 95% CI 0.89, 1.22) were not associated with dementia risk. After accounting for competing risk of death, joint SDI with air pollution was not associated with dementia risk (aHR = 1.06; 95% CI 0.87, 1.29). In stratified models, joint air pollution was associated with greater risk of dementia at high (aHR = 1.19; 95% CI 0.87, 1.63), but not at medium or low SDI.

CONCLUSION

Air pollution was associated with greater dementia risk in disadvantaged areas after accounting for competing risks. Air pollution associations with dementia incidence may be attenuated when other risk factors are more prominent in disadvantaged neighborhoods.

Dietary patterns and cognitive achievement among school children in socio-cultural context, a case of Montevideo, Uruguay

PURPOSE

The benefits of a healthy diet on children´s cognition have been described in several studies. However, many previous studies have analyzed the effect on general cognitive domains (e.g. intelligence), used measures based almost exclusively on local examinations, and rarely consider social context.

OBJECTIVE

The objective of the present study was to examine the relationship between two diet patterns and contextualized cognitive performance measures of children aged 6-8 years from low-average income neighborhoods in Montevideo, Uruguay.

METHODS

270 first-grade children with complete data participated in the study. Consumption of foods was determined via two averaged 24-h dietary recalls with the mother. Two dietary patterns were identified via principal component analysis: "processed (high calorie) foods" and "nutrient dense". Children´s cognitive performance, including general cognitive abilities, achievement in mathematics and reading, and discrepancy scores between predicted and actual achievement was assessed with the Woodcock-Muñoz Cognitive and Achievement scales. The association of dietary patterns and cognitive endpoints was analyzed in multilevel models, clustered by children´s school. Sociodemographic and biological variables were used as covariates.

RESULTS

The nutrient dense foods pattern, characterized by higher consumption of dark leafy and red-orange vegetables, eggs, beans & peas, potatoes, was associated with better performance in reading, with beta coefficient 3.28 (95% CI 0.02, 6.54). There was also an association between the nutrient dense foods factor and the Discrepancy in reading, 2.52 (0.17, 4.87). Processed (high calorie) foods pattern, characterized by higher consumption of breads, processed meats, fats and oils, sweetened beverages, and sweetened yogurt/dairy products; reduced intake of milk, pastries and pizza dinners was not associated with cognitive performance.

CONCLUSIONS

Nutrient dense food pattern was positively associated with children's reading achievement. A nutrient-rich diet may benefit written language acquisition at the beginning of schooling.

Environmental Exposure Disparities and Neurodevelopmental Risk: a Review

PURPOSE OF REVIEW

Neurotoxicant exposures are of particular concern in historically marginalized communities. Often a consequence of structural racism, low-income minoritized populations experience a disproportionate burden of hazardous exposures through proximity to industrial facilities, high traffic roads, and suboptimal housing. Here, we summarize reports on exposures and neurodevelopment focused on differences by education, income, race/ethnicity, or immigration status from 2015 to 2022, discuss the importance of such investigations in overburdened communities, and recommend areas for future research.

RECENT FINDINGS

We found 20 studies that investigated exposure disparities and neurodevelopment in children. Most were conducted in the USA, and many focused on air pollution, followed by metal exposures and water contamination. Although several studies showed differences in exposure-outcome associations by income and education, many examining differences by race/ethnicity did not report notable disparities between groups. However, measures of individual race and ethnicity are not reliable measures of discrimination experienced as a consequence of structural racism. Our review supports scientific evidence that the reduction of individual and widespread municipal exposures will improve child development and overall public health. Identified research gaps include the use of better indicators of economic status and structural racism, evaluations of effect modification and attributable fraction of outcomes by these factors, and considerations of multidimensional neighborhood factors that could be protective against environmental insults. Considering that vulnerable populations have disparities in access to and quality of care, greater burden of exposure, and fewer resources to incur associated expenses, such populations should be prioritized.

Reducing the complexity of high-dimensional environmental data: An analytical framework using LASSO with considerations of confounding for statistical inference

PURPOSE

Frameworks for selecting exposures in high-dimensional environmental datasets, while considering confounding, are lacking. We present a two-step approach for exposure selection with subsequent confounder adjustment for statistical inference.

METHODS

We measured cognitive ability in 338 children using the Woodcock-Muñoz General Intellectual Ability (GIA) score, and potential associated features across several environmental domains. Initially, 111 variables theoretically associated with GIA score were introduced into a Least Absolute Shrinkage and Selection Operator (LASSO) in a 50% feature selection subsample. Effect estimates for selected features were subsequently modeled in linear regressions in a 50% inference (hold out) subsample, first adjusting for sex and age and later for covariates selected via directed acyclic graphs (DAGs). All models were adjusted for clustering by school.

RESULTS

Of the 15 LASSO selected variables, eleven were not associated with GIA score following our inference modeling approach. Four variables were associated with GIA scores, including: serum ferritin adjusted for inflammation (inversely), mother's IQ (positively), father's education (positively), and hours per day the child works on homework (positively). Serum ferritin was not in the expected direction.

CONCLUSIONS

Our two-step approach moves high-dimensional feature selection a step further by incorporating DAG-based confounder adjustment for statistical inference.

Predicting Low-Level Childhood Lead Exposure in Metro Atlanta Using Ensemble Machine Learning of High-Resolution Raster Cells

Low-level lead exposure in children is a major public health issue. Higher-resolution spatial targeting would significantly improve county and state-wide policies and programs for lead exposure prevention that generally intervene across large geographic areas. We use stack-ensemble machine learning, including an elastic net generalized linear model, gradient-boosted machine, and deep neural network, to predict the number of children with venous blood lead levels (BLLs) ≥2 to <5 µg/dL and ≥5 µg/dL in ~1 km2 raster cells in the metro Atlanta region using a sample of 92,792 children ≤5 years old screened between 2010 and 2018. Permutation-based predictor importance and partial dependence plots were used for interpretation. Maps of predicted vs. observed values were generated to compare model performance. According to the EPA Toxic Release Inventory for air-based toxic release facility density, the percentage of the population below the poverty threshold, crime, and road network density was positively associated with the number of children with low-level lead exposure, whereas the percentage of the white population was inversely associated. While predictions generally matched observed values, cells with high counts of lead exposure were underestimated. High-resolution geographic prediction of lead-exposed children using ensemble machine learning is a promising approach to enhance lead prevention efforts.

Do Neighborhood Factors Modify the Effects of Lead Exposure on Child Behavior?

Lead exposure and neighborhoods can affect children’s behavior, but it is unclear if neighborhood characteristics modify the effects of lead on behavior. Understanding these modifications has important intervention implications. Blood lead levels (BLLs) in children (~7 years) from Montevideo, Uruguay, were categorized at 2 µg/dL. Teachers completed two behavior rating scales (n = 455). At one-year follow-up (n = 380), caregivers reported child tantrums and parenting conflicts. Multilevel generalized linear models tested associations between BLLs and behavior, with neighborhood disadvantage, normalized difference vegetation index (NDVI), and distance to nearest greenspace as effect modifiers. No effect modification was noted for neighborhood disadvantage or NDVI. Children living nearest to greenspace with BLLs < 2 µg/dL were lower on behavior problem scales compared to children with BLLs ≥ 2 µg/dL. When furthest from greenspace, children were similar on behavior problems regardless of BLL. The probability of daily tantrums and conflicts was ~20% among children with BLLs < 2 µg/dL compared to ~45% among children with BLLs ≥ 2 µg/dL when closest to greenspace. Furthest from greenspace, BLLs were not associated with tantrums and conflicts. Effect modification of BLL on child behavior by distance to greenspace suggests that interventions should consider both greenspace access and lead exposure prevention.

Prenatal predictors of postpartum depression trajectories from birth to 24 months amongst smoking women

AIMS AND OBJECTIVES

We aimed to identify postpartum depression (PPD) trajectories and examine relevant predictors amongst smoking women.

BACKGROUND

PPD can adversely affect families. Predictors of PPD trajectories amongst smoking women are understudied.

DESIGN

Longitudinal cohort study.

METHODS

A cohort of 49 U.S. women (current or ex-smoking) completed the Edinburgh Postnatal Depression Scale from birth to 24 months postpartum. Latent class growth modelling was used to identify PPD trajectories. Predictors of PPD trajectories were identified, adjusting for confounders. Effect modification by prenatal Patient Health Questionnaire (PHQ) depression score was also assessed. STROBE guidelines were followed in reporting results.

RESULTS

Three PPD trajectories were identified: non-PPD, transient PPD and chronic PPD. In multinomial logistic regression, social support was associated with lower odds of membership in the chronic PPD trajectory compared to non-PPD trajectory: being married or having a partner sharing resources (odds ratio OR = .14 [.02, .85], p-value = .03), greater partner support (OR = .87 [.77, .98], p-value = .02) and greater family/friends support (OR = .53 [.34, .82], p-value = .004). Transient PPD showed no differences with non-PPD on any predictors. In ordinal logistic regression models, social support was associated with lower odds of membership in a more severe PPD depression trajectory when prenatal PHQ depression score was in the low range (being married or having a partner sharing resources: p for effect modification = .06; partner support: p for effect modification = .05; and family/friends support: p for effect modification = .005).

RELEVANCE TO CLINICAL PRACTICE

Compared to the general population, chronic PPD trajectories were more common amongst smoking women. Social support was an important predictor of more severe PPD trajectories, especially when prenatal depression is low.

CONCLUSION

Our findings indicated that social support might decrease likelihood of severe PPD trajectories, especially when prenatal depression was low. Relevant predictors of transient PPD remained elusive.

Low-level exposure to lead, mercury, arsenic, and cadmium, and blood pressure among 8-17-year-old participants of the 2009-2016 National Health and Nutrition Examination Survey

BACKGROUND

Dysregulation of systolic, diastolic blood pressure (SBP, DBP), and pulse pressure (PP) in children may predict elevated blood pressure (BP) in adulthood. Toxicant exposure is widely studied as a risk factor for high BP in adults, but not in children. We assessed the joint associations between lead (Pb), mercury (Hg), arsenic (As), and cadmium (Cd) exposure and SBP, DBP, and PP among 8-17 year-old participants (n = 1642) of the 2009-2016 National Health and Nutrition Examination Survey (NHANES).

METHODS

Participants with at least two BP measures were included. Urinary As and Cd were adjusted for urinary creatinine concentrations. Blood Pb, Hg, and urinary As, Cd were natural log-transformed. Bayesian Kernel Machine Regression (BKMR) analyses were conducted to assess the associations between the toxicant mixture and BP measures. Multivariable regression models assessed the associations between individual toxicants, and the four toxicants simultaneously with each of the outcomes. Interactions with sodium intake were tested.

RESULTS

Exposure to all toxicants was low, with median (5%, 95%) level: Pb, 0.57 (0.26, 1.60) μg/dL; Hg, 0.37 (0.19, 2.12) μg/L; As, 5.61 (1.37, 33.2) μg/g creatinine, Cd, 0.06 (0.03, 0.23) μg/g creatinine. Toxicant mixture showed a statistically significant, inverse association with DBP, but not other BP measures. Linear regressions revealed no association between toxicants, individually or together, and BP measures. No evidence of interaction of sodium intake with any of the toxicants was observed.

CONCLUSIONS

In a nationally representative sample of 8-17 year-olds, we found suggestive inverse association of the mixture of low-level Pb, Hg, As, and Cd, with DBP. Longitudinal studies with multiple toxicants are needed to understand the interactive effects of toxicants on children's BP.

A mixed methods study examining neighborhood disadvantage and childhood behavior problems in Montevideo, Uruguay

BACKGROUND

Neighborhood disadvantage (ND) is a risk factor for child behavior problems (CBPs), but is understudied outside the United States and Europe. Our mixed methods study aims to (1) create a culturally meaningful measure of ND, (2) test cross-sectional associations between ND and CBPs and (3) qualitatively explore life in the neighborhoods of families participating in the Salud Ambiental Montevideo (SAM) study.

METHODS

The quantitative study (Study 1) comprised 272, ~7-year-old children with geolocation and complete data on twelve behavioral outcomes (Conner's Teachers Rating Scale - Revised Short Form: CTRS-R:S and Behavioral Rating Inventory of Executive Functioning: BRIEF). A ND factor was created at the census segment level (1,055 segments) with 19 potential indicators of ND downloaded from the Municipality of Montevideo Geographic Services. Children were assigned ND scores based on the location of their household within a census segment. Multilevel models tested associations between ND and all CBP scales, controlling for confounders at the individual level. The qualitative study (Study 2) comprised 10 SAM caregivers. Photovoice alongside semi-structured interviews in Spanish were used to foster conversations about neighborhood quality, activities, and raising children. Thematic analysis with inductive coding was used to summarize qualitative study findings.

RESULTS

The ND factor consisted of 12 census-based indicators related to education, employment, ethnicity, housing quality, and age characteristics, but unrelated to home ownership and some ethnicity variables. In multivariable models, ND was associated with greater conduct problems (β = 1.37, p < .05), poor shifting (β = 1.56, p < .01) and emotional control problems (β = 2.36, p < .001). Photovoice and semi-structured interviews yielded four themes: physical disorder, recreation, safety and crime, and community resources. Residents discussed improving waste management and transportation, updating playgrounds, and ensuring neighborhood safety.

CONCLUSIONS

ND in Montevideo comprised a unique set of census indicators. ND was primarily related to behavioral regulation problems. Hypothesized pathways whereby ND affects CBPs are discussed.

Internalizing symptoms and cannabis and alcohol use: Between- and within-person risk pathways with coping motives

OBJECTIVE

To test reciprocal associations among internalizing symptoms (depression and social anxiety), using alcohol and cannabis to cope, and use-related problems.

METHOD

The study utilized a community sample (N = 387, 55% female; majority non-Hispanic Caucasian (83.1%) or African American (9.1%) and a longitudinal design that spanned 17 to 20 years of age, and distinguished within- and between-person associations using latent curve models with structured residuals.

RESULTS

Reciprocal prospective within-person associations were supported for alcohol, such that elevated depression symptoms were associated with increased alcohol coping motivates 1 year later, which, in turn, was associated with subsequent increased depression symptoms. Bidirectional associations were not supported for social anxiety, although high levels of social anxiety were associated with elevated levels of coping drinking 1 year later. Cannabis coping motives were associated with exacerbation of depression, but not social anxiety symptoms, 1 year later. Between- and within-person contemporaneous associations suggested that depression and social anxiety were more strongly associated with coping than social/enhancement motives, and that coping motives were associated with use-related problems.

CONCLUSION

Findings suggest that alcohol coping motivates exacerbate rather than ameliorate depression symptoms, which, in turn, leads to greater reliance on alcohol to cope. There was more consistent support for associations with substance use-related problems for depression than for social anxiety. Both between- and within-person associations may be useful for identifying targets and timing of coping-oriented interventions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Latent subgroups of cognitive performance in lead- and manganese-exposed Uruguayan children: Examining behavioral signatures

OBJECTIVES

Lead (Pb) and manganese (Mn) are confirmed neurotoxins but it is unclear to what extent low-level exposure produces a unique behavioral signature. The objective of this study was to investigate latent cognitive profiles among children (6-8 years) from Montevideo, Uruguay co-exposed to these metals.

METHOD

Among 345 children, blood Pb and hair Mn were measured using atomic absorption spectroscopy and ICP-MS, respectively. Sixteen measures, reflecting multiple domains of cognitive functioning were gathered: (1) three tests from Cambridge Neuropsychological Test Automated Battery (CANTAB): Intra-Extra Dimensional Shift (IED), Spatial Span (SSP) and Stockings of Cambridge (SOC), (2) ten tasks from Woodcock-Muñoz Achievement Battery, Revised (WM): Visual-Motor Integration, Verbal Comprehension (Vocabulary, Synonyms, Antonyms, Analogies), Visual-Auditory Comprehension, Concept Formation, Visual Spatial Thinking, Number Inversion and Spatial Relations, (3) Bender Gestalt task, and (4) Weschler block design task. Scores were modeled using latent profile analysis (LPA). Association between blood Pb and hair Mn on performance profiles was assessed using ordinal regression, controlling for confounders. An interaction between Pb and Mn was tested.

RESULTS

Mean ± SD of blood Pb was 4.1 ± 2.1 μg/dL and 35% of children had blood Pb ≥ 5 μg/dL. Median [5%, 95%] hair Mn level was 0.8 [0.3, 4.1] ppb. Three latent cognitive performance profiles were identified: high (n = 46, 13%), average (n = 209, 61%) and low (n = 90, 26%). Each one-unit increase in blood Pb was associated with a 28% greater likelihood of belonging to a poorer-performing profile. The association was non-linear, with the effect of Pb on profile membership strongest at lower levels of exposure. There was no meaningful interaction between Pb and Mn.

CONCLUSIONS

A behavioral signature for low-level Pb & Mn exposure was not identified, but the likelihood of membership in low-performing profile was higher at lowest levels of blood Pb. There was no effect measure modification between Pb and Mn. Future research should address how complex environments created by chemical exposures and the social context relate to cognitive performance in young children.

Internalizing and Externalizing Problem Behavior: a Test of a Latent Variable Interaction Predicting a Two-Part Growth Model of Adolescent Substance Use

Externalizing symptoms robustly predict adolescent substance use (SU); however, findings regarding internalizing symptoms have been mixed, suggesting that there may be important moderators of the relationship between internalizing problems and SU. The present study used a longitudinal community sample (N = 387, 55% female, 83% White) to test whether externalizing symptoms moderated the relationship between internalizing symptoms and trajectories of alcohol and marijuana use from early (age 11-12 years old) to late (age 18-19 years old) adolescence. Two-part latent growth models were used to distinguish trajectories of probability of use from trajectories of amount of use among users. Results suggested that externalizing symptoms moderated the association between internalizing symptoms and probability of alcohol, but not marijuana use. The highest probability of alcohol use was observed at high levels of externalizing symptoms and low levels of internalizing symptoms. A negative protective effect of internalizing symptoms on probability of alcohol use was strongest in early adolescence for youth high on externalizing symptoms. Although moderation was not supported for amount of use among users, both domains of symptomology were associated with amount of alcohol and marijuana use as first-order effects. High levels of externalizing symptoms and low levels of internalizing symptoms were associated with high levels of amount of use among users. These findings suggest that developmental models of substance use that incorporate internalizing symptomology should consider the context of externalizing problems and distinguish probability and amount of use.

The Prospective Association Between Internalizing Symptoms and Adolescent Alcohol Involvement and the Moderating Role of Age and Externalizing Symptoms

BACKGROUND

As predicted by self-medication theories that drinking is motivated by a desire to ameliorate emotional distress, some studies find internalizing symptoms (e.g., anxiety, depression) increase risk of adolescent drinking; however, such a risk effect has not been supported consistently. Our prior work examined externalizing symptoms as a potential moderator of the association between internalizing symptoms and adolescent alcohol use to explain some of the inconsistencies in the literature. We found that internalizing symptoms were protective against early adolescent alcohol use particularly for youth elevated on externalizing symptoms (a 2-way interaction). Our sample has now been followed for several additional assessments that extend into young adulthood, and the current study tests whether the protective effect of internalizing symptoms may change as youth age into young adulthood, and whether this age-moderating effect varied across different clusters of internalizing symptoms (social anxiety, generalized anxiety, and depression). Internalizing symptoms were hypothesized to shift from a protective factor to a risk factor with age, particularly for youth elevated on externalizing symptoms.

METHODS

A community sample of 387 adolescents was followed for 9 annual assessments (mean age = 12.1 years at the first assessment and 55% female). Multilevel cross-lagged 2-part zero-inflated Poisson models were used to test hypotheses.

RESULTS

The most robust moderating effects were for levels of alcohol use, such that the protective effect of all internalizing symptom clusters was most evident in the context of moderate to high levels of externalizing problems. A risk effect of internalizing symptoms was evident at low levels of externalizing symptoms. With age, the risk and protective effects of internalizing symptoms were evident at less extreme levels of externalizing behavior. With respect to alcohol-related problems, findings did not support age moderation for generalized anxiety or depression, but it was supported for social anxiety.

CONCLUSIONS

Findings highlight the importance of considering the role of emotional distress from a developmental perspective and in the context of externalizing behavior problems.

Remote assessment of verbal memory in MS patients using the California Verbal Learning Test

We used the California Verbal Learning Test, Second Edition (CVLT-II), one component of the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS), to determine feasibility of a remote assessment protocol. We compared telephone-administered CVLT-II data from MS patients to data acquired in person from an independent sample of patients and healthy controls. Mixed factor analyses of variance (ANOVAs) showed no significant differences between patient groups, but between-group effects comparing patients and healthy controls were significant. In this study, CVLT-II assessment by conventional in-person and remote telephone assessment yielded indistinguishable results. The findings indicate that telephone-administered CVLT-II is feasible. Further validation studies are underway.

Differential effects of aging on motor and cognitive functioning in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) patients are impaired in motor and cognitive performance, but the extent to which these deficits are magnified by aging is unknown. In one prior study, differences in cognitive processing speed between MS patients and healthy individuals were of similar magnitude across the lifespan. Here, we have improved on this work by expanding assessment to multiple cognitive domains and motor functioning.

OBJECTIVE

To determine whether the degree of cognitive and motor dysfunction in MS is magnified with increasing age.

METHODS

In all, 698 MS patients (aged 29-71 years) and 226 healthy controls (HCs; aged 18-72 years) completed neuroperformance tests covering ambulation, upper extremity function, information processing speed, and memory.

RESULTS

Linear regression models predicting cognitive and motor function revealed main effects of MS/HC diagnosis, age, and education across all measures. There was also an interaction between age and diagnosis on measures of motor function, but not on cognitive outcomes.

CONCLUSION

The progression of motor decline is amplified by aging in MS. However, the degree of cognitive impairment does not vary across the lifespan. Thus, evidence of accelerated cognitive impairment in older adults with MS may signal the presence of other age-related cognitive pathologies.