Community violence and cellular and cytokine indicators of inflammation in adolescents.

Neighborhood violence is associated with a range of health consequences but little is known about the biological processes involved. Research in disease pathogenesis has identified low-grade inflammation as a process that, beginning in the first decades of life, is both induced by chronic stress and a contributor to multiple cardiometabolic diseases that present throughout the lifecourse. Previous research has examined whether neighborhood violence is associated with inflammatory biomarkers, but has been limited to cytokine indicators of inflammation. In a sample of adolescents (n = 203) residing in Chicago, we tested cross-sectional associations between neighborhood violence and cellular and cytokine indicators of inflammation. Neighborhood-level violence was measured in multiple ways (as murder rates of Census block groups and as the sum of homicides within 1 and ½ mile zones) in the areas surrounding where youth lived and attended school. At the individual level, violence exposure was measured by self-report (direct victimization, witnessing violence, and/or victimization of family or friends in the past year). Adolescents residing in high-violence neighborhoods evidenced higher numbers of pro-inflammatory classical (CD14++CD16-) monocytes relative to those in less violent neighborhoods. In contrast, neighborhood-level violence was not consistently associated with cytokine levels across different model specifications. Self-reported violence exposure was also not consistently associated with inflammatory biomarkers. Neighborhood-level violence and self-reported violence exposure interacted, such that the positive association between neighborhood-level violence and classical monocytes was observed only among adolescents who reported being exposed to violence. Associations were largely specific to the neighborhoods in which youth lived as opposed to those in which they attended school. Findings provide the first evidence that youth residing in high-violence neighborhoods show mobilization of classical monocytes, suggesting a pro-inflammatory mechanism through which contextual stressors such as neighborhood violence may compromise health.

Outward subcortical curvature associated with sub-clinical depression symptoms in adolescents.

OBJECTIVE: Subclinical or subthreshold depressive symptoms (StD) are frequent in adolescence and are related to suicidality and onset of depression in adulthood, however, their neurobiology is poorly understood. We examined the relationship between StD and subcortical grey matter structures in unmedicated adolescents with no history of axis I diagnosis. METHODS: 277 youths from Chicago aged 14 years participated, undergoing a structural MRI scan and completing the Revised Children's Anxiety and Depression Scale (RCADS). Blood samples provided a composite of five pro-inflammatory cytokines. Regions of interest (ROI) for vertex-based surface analysis were the left and right amygdala, hippocampus, thalamus, caudate, nucleus accumbens, pallidum and putamen. Covariates were age, pubertal status, socioeconomic disadvantage and intracranial volume. Males and females were analysed separately. RESULTS: StD had positive associations (outward shape) with subcortical morphology in the right amygdala and left hippocampus in females, and the bilateral putamen and the left caudate, hippocampus and thalamus in males. However, we also found negative associations with StD (inward contractions) in the hippocampus in females and the caudate in males. Pro-inflammatory cytokines did not mediate the relationship between StD and outward morphology or volume. CONCLUSION: This is one of the first studies to examine subcortical morphology of basal ganglia and thalamic regions related to StD in adolescents, and the first study to report mostly positive associations between StD, volume and outward morphology in youths. These findings could reflect intact neurogenesis or resilience to depression, however longitudinal research is needed to further understand the neurobiology of StD in adolescents.

Subcortical structural variations associated with low socioeconomic status in adolescents.

Low socioeconomic status (SES) is associated with a higher probability of multiple exposures (e.g., neighborhood violence, poor nutrition, housing instability, air pollution, and insensitive caregiving) known to affect structural development of subcortical brain regions that subserve threat and reward processing, however, few studies have examined the relationship between SES and such subcortical structures in adolescents. We examined SES variations in volume and surface morphometry of subcortical regions. The sample comprised 256 youth in eighth grade (mean age = 13.9 years), in whom high dimensional deformation mapping of structural 3T magnetic resonance imaging scans was performed. Vertex-wise linear regression analyses examined associations between income to poverty ratio and surfaces of the hippocampus, amygdala, thalamus, caudate, putamen, nucleus accumbens and pallidum, with the covariates age, pubertal status, and intracranial volume. Given sex differences in pubertal development and subcortical maturation at this age, the analyses were stratified by sex. Among males, who at this age average an earlier pubertal stage than females, the relationship between SES and local shape variation in subcortical regions was almost entirely positive. For females, the relationship between SES and local shape variation was negative. Racial identity was associated with SES in our sample, however supplementary analyses indicated that most of the associations between SES and subcortical structure were independent of it. Although these cross-sectional results are not definitive, they are consistent with a scenario where low SES delays structural maturation of subcortical regions involved with threat and reward processing. Future longitudinal studies are needed to test this hypothesis.

Academic disparities and health: How gender-based disparities in schools relate to boys' and girls' health.

RATIONALE: Recent research reveals that, although girls encounter some barriers in school (e.g., in science and math), on balance, boys perform worse academically. Moreover, other research has identified a correlation between exposure to a context characterized by large disparities in performance or resources and a range of negative outcomes, including negative health and well-being, among members of lower status groups. OBJECTIVE: Building on these literatures, the present research tests the relationship between gender disparities in academic performance within a school and students' health outcomes. Specifically, we investigated whether boys had worse health when they attended schools where there was a greater disparity between boys' and girls' academic performance. METHOD: We tested this hypothesis in two different samples with different health outcomes. In a sample of healthy eighth graders (Study 1; 159 girls and 81 boys), we assessed two indices of metabolic syndrome, and in a sample of children with asthma (Study 2; 122 girls and 153 boys), we assessed immune function (Th1 and Th2 cytokine production) and self-reported symptoms. Participants in both samples also reported the name of the school that they attended so that we could access publicly available information about the percentage of girls and the percentage of boys in each school who met expectations for their grade level on standardized tests. RESULTS: In both samples, the greater the gap in a school between the percentage of girls and the percentage of boys who met expectations for their grade level on standardized tests, the worse boys' health. This pattern did not emerge among girls. CONCLUSION: Results thus highlight the negative health correlates of academic disparities among members of lower-performing groups.