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

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.

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.

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.