Cumulative socioeconomic status risk, allostatic load, and adjustment: a prospective latent profile analysis with contextual and genetic protective factors

Stress-Related Biosocial Mechanisms of Discrimination and African American Health Inequities

This review describes stress-related biological mechanisms linking interpersonal racism to life course health trajectories among African Americans. Interpersonal racism, a form of social exclusion enacted via discrimination, remains a salient issue in the lives of African Americans, and it triggers a cascade of biological processes originating as perceived social exclusion and registering as social pain. Exposure to discrimination increases sympathetic nervous system activation and upregulates the HPA axis, increasing physiological wear and tear and elevating the risks of cardiometabolic conditions. Consequently, discrimination is associated with morbidities including low birth weight, hypertension, abdominal obesity, and cardiovascular disease. Biological measures can provide important analytic tools to study the interactions between social experiences such as racial discrimination and health outcomes over the life course. We make future recommendations for the study of discrimination and health outcomes, including the integration of neuroscience, genomics, and new health technologies; interdisciplinary engagement; and the diversification of scholars engaged in biosocial inequities research.

Childhood poverty, catecholamines, and substance use among African American young adults: The protective effect of supportive parenting

From a sample of African American families living in the rural South, this study tested the hypothesis that growing up in poverty is associated with heightened biological stress levels in youth that, in turn, forecast elevations in drug use in young adulthood. Supportive parenting during adolescence was hypothesized to protect youth's biological stress levels from rising in the context of poverty. African American youth and their primary caregivers from 385 families participated in a 14-year prospective study that began when youth were 11 years of age. Data were collected from 2001 to 2016. All families lived in impoverished communities in the rural South. Linear regression models and conditional indirect effect analyses were executed in 2016 to test the study hypotheses. High number of years living in poverty across adolescence was associated with high catecholamine levels, but only among those youth who received low levels of supportive parenting. Youth catecholamine levels at age 19 forecast an increase in substance use from age 19 to age 25. Conditional indirect effects confirmed a developmental cascade linking family poverty, youth catecholamine levels, and increases in substance use for youth who did not receive high levels of supportive parenting. Current results suggest that, for some African American youth, substance use vulnerability may develop "under the skin" from stress-related biological weathering years before elevated drug use. Receipt of supportive parenting, however, can protect rural African American youth from biological weathering and its subsequent effects on increases in substance use during adulthood.

Age sensitive associations of adolescent substance use with amygdalar, ventral striatum, and frontal volumes in young adulthood

INTRODUCTION

This study evaluated an age sensitive model of substance use across adolescence to determine if substance use was associated with smaller volumes for an earlier developing brain region, the amygdala, a later developing region, the inferior frontal gyrus, and the ventral striatum.

METHOD

Participants (N = 110) were African American young adults who were members of a longitudinal cohort across childhood and adolescence. Measures of substance use were collected across early (ages 12-15 yrs.), middle (ages 16-18 yrs.), and later (ages 19-21 yrs.) adolescence; then, at age 25, a representative subset of the sample completed magnetic resonance imaging (MRI) that assessed regional brain volumes.

RESULTS

Higher levels of substance use during early adolescence, but not middle or later adolescence, were significantly associated with smaller amygdalar volume in young adulthood. Higher levels of substance use during middle adolescence, but not early or later adolescence, were significantly associated with smaller pars opercularis volume. Substance use was not associated with the pars triangularis or ventral striatum.

CONCLUSION

These findings support age sensitive associations between substance use and smaller gray matter volumes at age 25 and are consistent with literature supporting the differential nature of substance use and brain maturation across adolescence and into young adulthood.

Unsupportive parenting moderates the effects of family psychosocial intervention on metabolic syndrome in African American youth

BACKGROUND/OBJECTIVE

Family relationships have been linked to obesity and related disorders in youth, but few studies have provided causal evidence of this association. This study tested the impact of a family psychosocial intervention on components of metabolic syndrome-a condition driven largely by abdominal obesity-in African American youth. In particular, the study tested whether effects were strongest among those who started at highest risk, that is, with high levels of unsupportive parenting at baseline.

SUBJECTS/METHODS

Randomized clinical trial of a community sample of 391 African American youth (mean age=11.2 years) conducted in 2001-2002, with follow-up metabolic syndrome assessment in 2014-2015. Participants were assigned either to receive a weekly family intervention or to a control group. The primary study outcome was the number of components of metabolic syndrome that were clinically elevated at age 25, including central adiposity, blood pressure, triglycerides, glucose and low high-density lipoproteins. Unsupportive parenting was measured by questionnaires at baseline.

RESULTS

Significant interaction effects were found between group assignment and baseline unsupportive parenting on counts of metabolic syndrome components in youth (beta=-0.17, P=0.03). Among those who started with higher levels of unsupportive parenting at age 11, participation in the family intervention reduced the number of clinically elevated components of the metabolic syndrome at age 25 relative to the control group. No such effect was seen among those who started with good parenting. Mediation analyses suggested that changes in the psychosocial targets of the parenting intervention partially accounted for the effects amongst those high in unsupportive parenting at baseline (effect size=-0.350, s.e.=0.178).

CONCLUSIONS

These findings suggest that efforts to improve family relationships may be able to ameliorate the detrimental effects that harsh and unsupportive parenting have on obesity-related outcomes such as metabolic syndrome in youth.

Profiles of Contextual Risk at Birth and Adolescent Substance Use

This study examined whether there are subgroups of families with distinct profiles of prenatal/birth contextual risk, and whether subgroup membership was differentially related to adolescent substance use. Data from the Northern Finland Birth Cohort 1986 were used. A five-class model provided the most meaningful solution. Large Family Size (7.72%) and Low Risk (69.69%) groups had the lowest levels of alcohol, cigarette, and illegal drug use. Similar high levels for each of the three substance-related outcomes were found for Parent Substance Misuse (11.20%), Maternal School Dropout (4.66%), and Socioeconomic Disadvantage (6.72%) groups. Maternal smoking and drinking while pregnant and paternal heavy alcohol use were found to be key prenatal risk factors that tended to cluster together and co-occur with other prenatal risk factors differently for different subgroups of youth.

Identifying diverse life transition patterns from adolescence to young adulthood: The influence of early socioeconomic context

The purposes of the present study are to investigate: (1) the heterogeneity in life transition patterns of youth from adolescence to young adulthood (ages 18-30) involving the timing and sequence of four transition events (college graduation, full-time employment, marriage, and parenthood), (2) the influence of early socioeconomic adversity on life transition patterns from adolescence to young adulthood, and (3) the influence of gender and race/ethnicity on these transition patterns. Using a multivariate discrete-time mixture survival model with a sample of 14,503 adolescents from the National Longitudinal Study of Adolescent to Adult Health (Add Health), the study identified four life transition patterns and found that early socioeconomic adversity shapes disrupted life transition patterns from adolescence to young adulthood. Gender and race/ethnicity differences are discussed. These results highlight the need for prevention and intervention programs that selectively target at-risk youth beginning in adolescence and continuing through subsequent transition periods.

John Henryism Coping and Metabolic Syndrome Among Young Black Adults

OBJECTIVE

The aim of the study was to test the novel hypothesis that, among black Americans who used John Henryism coping, those from low socioeconomic status backgrounds would be more likely to develop metabolic syndrome than those from higher socioeconomic backgrounds.

METHODS

This is an ancillary analysis of Strong African American Families Healthy Adult Program, a longitudinal cohort of 391 black youths and their caregivers. From ages 11 to 18 years, family socioeconomic status was assessed. At age 25 years, John Henryism was assessed, blood samples were drawn, and measurements were taken of blood pressure and waist circumference. Metabolic syndrome status was based on International Diabetes Federation guidelines.

RESULTS

A significant interaction emerged between family socioeconomic disadvantage and John Henryism coping in predicting metabolic syndrome diagnosis (odds ratio = 1.047, 95% confidence interval = 1.004-1.091). Participants who were high in John Henryism coping were more likely to display metabolic syndrome if they were from disadvantaged backgrounds (predicted prevalence of 26.7%) than if they were from more privileged backgrounds (predicted prevalence of 9.6%).

CONCLUSIONS

These patterns illustrate for the first time that John Henryism coping can undermine cardiometabolic health among black youths from disadvantaged backgrounds.

Buffering effects of safe, supportive, and nurturing relationships among women with childhood histories of maltreatment

BACKGROUND

Adults who were victims of childhood maltreatment tend to have poorer health compared with adults who did not experience abuse. However, many are in good health. We tested whether safe, supportive, and nurturing relationships buffer women with a history of childhood maltreatment from poor health outcomes in later life.

METHODS

Participants included women from the Environmental Risk (E-Risk) Longitudinal Twin Study who were involved in an intimate relationship at some point by the time their twin children were 10 years old. Women were initially interviewed in 1999-2000 (mean age = 33 years) and 2, 5, and 7 years later. They reported on their physical and mental health, and their health-risk behaviours.

RESULTS

Compared with women who did not experience abuse in childhood, women with histories of maltreatment were at elevated risk for mental, physical, and health-risk behaviours, including major depressive disorder, sleep, and substance use problems. Cumulatively, safe, supportive, and nurturing relationships characterized by a lack of violence, emotional intimacy, and social support buffered women with a history of maltreatment from poor health outcomes.

CONCLUSIONS

Our findings emphasize that negative social determinants of health - such as a childhood history of maltreatment - confer risk for psychopathology and other physical health problems. If, however, a woman's current social circumstances are sufficiently positive, they can promote good health, particularly in the face of past adversity.

Parenting Intervention at Age 11 and Cotinine Levels at Age 20 Among African American Youth

OBJECTIVES

This study was designed to test the hypothesis that African American preadolescents who participated in a family-centered parenting intervention at age 11 would show lower levels of cotinine, a biomarker for recent smoking, at age 20 than would similar participants in the control condition. The study was also designed to test the hypothesis that prevention-induced increases in supportive parenting would account for any prevention effects that emerged.

METHODS

African American parents and their 11-year-old children in the rural southern United States were assigned randomly to the Strong African American Families program or to a control condition. Parents provided self-reported data on supportive parenting when the youth were 11 and 16 years of age. When the youth were 20 years of age, blood was drawn from which cotinine was assayed.

RESULTS

Intervention program participants (M = 0.672, SD = 0.048) displayed significantly lower cotinine levels at age 20 years than did control participants (M = 0.824, SD = 0.059), P = .046. Mediation analyses confirmed that increases in supportive parenting accounted for intervention effects on smoking.

CONCLUSIONS

We have demonstrated in this study that a randomized trial of a prevention program designed to enhance supportive parenting reduced cotinine levels among young African American adults. The developmentally appropriate family-centered intervention buffered the risk of smoking 9 years after program participation.

Measuring Stress in Young Children Using Hair Cortisol: The State of the Science

Extensive literature suggests that adverse experiences in early childhood may deleteriously impact later health. These effects are thought to be related to the impact of persistent or chronic stress on various biological processes, mediated by dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, and ultimately irregularities in cortisol levels. Ameliorating persistent stress in young children requires accurately measuring the chronicity of physiologic stress, which is difficult in young children because of unreliable self-report and the burden and inaccuracy associated with using invasive acute-stress biomeasures. A better way to approximate persistent stress in young children is measuring hair cortisol concentration (HCC), as it only requires one noninvasive collection to measure months of HPA-axis activity or experienced stress. However, few studies measure HCC in young children despite wide use in adult stress research. This article reviews and synthesizes research that uses HCC to approximate persistent stress in healthy children, 12-60 months of age. Reviewed studies indicate that HCC is elevated in young children who are experiencing forms of persistent stress such as low socioeconomic status and maternal distress. Hair cortisol is thus a promising measure of early childhood persistent stress, but due to the limited use of HCC in this population, much research is still needed. Specifically, nurse researchers may need to measure several factors associated with early childhood persistent stress and HCC to identify which children are at risk for stress-related disease.

Genetic moderation of multiple pathways linking early cumulative socioeconomic adversity and young adults' cardiometabolic disease risk

Recent research suggests that psychosocial resources and life stressors are mediating pathways explaining socioeconomic variation in young adults' health risks. However, less research has examined both these pathways simultaneously and their genetic moderation. A nationally representative sample of 11,030 respondents with prospective data collected over 13 years from the National Study of Adolescent to Adult Health was examined. First, the association between early cumulative socioeconomic adversity and young adults' (ages 25-34) cardiometabolic disease risk, as measured by 10 biomarkers, through psychosocial resources (educational attainment) and life stressors (accelerated transition to adulthood) was examined. Second, moderation of these pathways by the serotonin transporter linked polymorphic region gene (5-HTTLPR) was examined. There was evidence for the association between early socioeconomic adversity and young adults' cardiometabolic disease risk directly and indirectly through educational attainment and accelerated transitions. These direct and mediating pathways were amplified by the 5-HTTLPR polymorphism. These findings elucidate how early adversity can have an enduring influence on young adults' cardiometabolic disease risk directly and indirectly through psychosocial resources and life stressors and their genetic moderation. This information suggests that effective intervention and prevention programs should focus on early adversity, youth educational attainment, and their transition to young adulthood.

Predictors of Depressive Symptoms in Emerging Adulthood in a Low-Income Urban Cohort

This study examined predictors of depressive symptoms in emerging adulthood in a sample of 1,142 individuals (94% African American) who grew up in urban poverty. Data were drawn from a longitudinal study that followed participants from age five and included participant, parent, and teacher surveys, and administrative records. Depressive symptoms were self-reported at age 22-24 using a modified version of the Brief Symptom Inventory (BSI; Derogatis, 1975). Binary logistic regression analyses identified several significant predictors of depressive symptoms in emerging adulthood, including: sex, adverse childhood experiences (ACE) score, socio-emotional adjustment in the classroom, juvenile arrest, and on-time graduation. Significant sex differences were also detected, with the final models fitting the male sample better than the full study or female samples. Implications for future research and intervention are discussed.

Cumulative Risk and Physiological Stress Responses in African American Adolescents

OBJECTIVE

To investigate associations between components of cumulative risk (CR) and physiological stress responses in African American adolescents and evaluate emotion regulation as a mediator and sex as a moderator of these associations.

METHODS

Cortisol and salivary alpha amylase (sAA) were collected in adolescents ( N = 205; 55% female; 12.1 ± 1.6 years at baseline) as part of a longitudinal study of stress and adjustment in families. CR was assessed at baseline and emotion regulation was assessed at baseline and 2 years later at Wave 3 (W3) using caregiver and adolescent reports. Cortisol and sAA responses to the social competence interview were assessed at W3.

RESULTS

Repeated-measures analyses of variance predicting cortisol and controlling for time of day, adolescent age, medication usage, and pubertal status revealed significant interactions of time with both psychosocial and sociodemographic risk. In both analyses, youths with higher levels of risk showed a steeper decline in cortisol than youths with lower levels of risk. In parallel analyses predicting sAA, time interacted with psychosocial but not with sociodemographic risk. There were no interactions with sex in any of the analyses. Although CR was associated with changes in emotion regulation, there was no evidence that these changes accounted for the observed CR-stress response associations.

CONCLUSIONS

These findings illustrate the potential importance of disentangling CR and suggest that additional work is needed to help explicate why and how CR is associated with specific physiological responses to stress.

Difficult Family Relationships, Residential Greenspace, and Childhood Asthma

BACKGROUND AND OBJECTIVES

Both the social environment and the physical environment are increasingly recognized as important to childhood diseases such as asthma. This study tested a novel hypothesis: that living in areas high in greenspace may help buffer the effects of difficult family relationships for children with asthma.

METHODS

A total of 150 children (ages 9-17), physician-diagnosed with asthma, participated in this study. To assess difficulties in parent-child relationships, parents and children completed measures of harsh/inconsistent parenting and parental hostility. Residential greenspace was calculated by using satellite-derived Normalized Difference Vegetation Index with a buffer of 250 m around the residential address. Outcomes included both clinical and biological measures: asthma control and functional limitations, as well as airway inflammation (fractional concentration of exhaled nitric oxide) and glucocorticoid receptor expression in T-helper cells.

RESULTS

After controlling for potential confounding variables, including family income, child demographics, and child medical variables, few main effects were found. However, interactions between residential greenspace and difficult family relationships were found for asthma control (P = .02), asthma functional limitations (P = .04), airway inflammation (P = .007), and the abundance of glucocorticoid receptor in T-helper cells (P = .05). These interactions were all in a direction such that as the quality of parent-child relationships improved, greenspace became more strongly associated with better asthma outcomes.

CONCLUSIONS

These findings suggest synergistic effects of positive environments across the physical and social domains. Children with asthma appear to benefit the most when they both live in high greenspace areas and have positive family relationships.

Preschoolers' genetic, physiological, and behavioral sensitivity factors moderate links between parenting stress and child internalizing, externalizing, and sleep problems

This study examined three potential moderators of the relations between maternal parenting stress and preschoolers' adjustment problems: a genetic polymorphism-the short allele of the serotonin transporter (5-HTTLPR, ss/sl allele) gene, a physiological indicator-children's baseline respiratory sinus arrhythmia (RSA), and a behavioral indicator-mothers' reports of children's negative emotionality. A total of 108 mothers (M_age  = 30.68 years, SD_age  = 6.06) reported on their parenting stress as well as their preschoolers' (M_age  = 3.50 years, SD_age  = 0.51, 61% boys) negative emotionality and internalizing, externalizing, and sleep problems. Results indicated that the genetic sensitivity variable functioned according to a differential susceptibility model; however, the results involving physiological and behavioral sensitivity factors were most consistent with a diathesis-stress framework. Implications for prevention and intervention efforts to counter the effects of parenting stress are discussed.

Resilience to adversity and the early origins of disease

For the past quarter century, scientists at the Center for Family Research at the University of Georgia have conducted research designed to promote understanding of normative developmental trajectories among low socioeconomic status African American children, youths, and young adults. In this paper, we describe a recent expansion of this research program using longitudinal, epidemiological studies and randomized prevention trials to test hypotheses about the origins of disease among rural African American youths. The contributions of economic hardship, downward mobility, neighborhood poverty, and racial discrimination to allostatic load and epigenetic aging are illustrated. The health benefits of supportive family relationships in protecting youths from these challenges are also illustrated. A cautionary set of studies is presented showing that some psychosocially resilient youths demonstrate high allostatic loads and accelerated epigenetic aging, suggesting that, for some, "resilience is just skin deep." Finally, we end on an optimistic note by demonstrating that family-centered prevention programs can have health benefits by reducing inflammation, helping to preserve telomere length, and inhibiting epigenetic aging.

Children's Physical Resilience Outcomes: Meta-Analysis of Vulnerability and Protective Factors

Resilience has generally been understood as positive coping and adaptation despite stress and adversity and as a buffer against stress. Researchers examining resilience have typically focused on children's psychological resilience because of the well-established impact of stress on children's mental health. However, although it has also been well-established that high levels of stress can impact children's physical health, their physical health has received little attention in resilience research.

ELIGIBILITY CRITERIA

Articles were selected for review if they (1) had a variable that was in some way a measure of physical health in response to a psychosocial stressor; (2) had participants who were children or adolescents within the age range of 4-18years; and (3) were a peer-reviewed, empirical study.

SAMPLE

Two random-effect meta-analyses were conducted with a sample of 12,772 participants across 14 studies to determine the influence of protective and vulnerability factors on children's physical health in adverse experiences.

RESULTS

Protective factors had a moderate effect and vulnerability factors had a small-moderate effect on health measures across domains of physiological, sleep behavior, and overall health. The type of health measure moderated the effect size for vulnerability factors, but not for protective factors.

CONCLUSIONS

These findings suggest that protective factors may be associated with an environment that encourages children to thrive, as apparent by their physical health.

IMPLICATIONS

The results of this review and meta-analysis can be used to guide the methodological design of future studies on childhood resilience and to inform clinical practice with children and adolescents.

Victimization and Biological Stress Responses in Urban Adolescents: Emotion Regulation as a Moderator

Associations between urban adolescents' victimization experiences and biological stress responses were examined, as well as emotion regulation as a moderator of these associations. Data from a 4-wave longitudinal study with a low-income, community-based sample (n = 242; 91 % African American; 57 % female; M = 11.98, SD = 1.56 years at baseline) revealed that victimization, assessed over 3 study waves, was associated with an attenuated cortisol response to a stress interview at the final study wave, indicating that responses of the Hypothalamus-Pituitary-Adrenal (HPA) axis were dysregulated. Cortisol responses were moderated by caregiver-reported adolescent emotion regulation, suggesting that this modifiable protective factor that is taught in many school-based prevention programs could help reduce harm associated with HPA axis dysregulation linked to victimization.

Black-White Disparity in Young Adults' Disease Risk: An Investigation of Variation in the Vulnerability of Black Young Adults to Early and Later Adversity

PURPOSE

Socioeconomic adversity in early years and young adulthood are risk factors for poor health in young adulthood. Population differences in exposure to stressful socioeconomic conditions partly explain the higher prevalence of disease among black young adults. Another plausible mechanism is that blacks are differentially vulnerable to socioeconomic adversity (differential vulnerability hypothesis), which has not been adequately investigated in previous research. The present study investigated variation in the vulnerability of black young adults leading to cardiometabolic (CM) disease risk.

METHODS

We used a nationally representative sample of 8,824 adolescents who participated in the Add Health study. Early and later adversity was measured using a cumulative index of social and material adversity in adolescence and young adulthood. CM disease risk was assessed using nine biomarkers. Path analysis within a structural equation modeling framework was used.

RESULTS

The findings indicated that both early and later socioeconomic adversity act as stressors with independent additive influences on young adults' CM disease risk, consistent with the differential exposure hypothesis. Moreover, the results showed that black youth are less vulnerable to early socioeconomic adversity than whites, but they are more vulnerable to later adversity.

CONCLUSIONS

The findings provide support for the unique and additive influences of early and later socioeconomic adversity on CM disease risk contributing to the black-white health disparity in young adulthood. The results also suggest that vulnerability to adversity varies depending on the life stage, which highlights the need for life-stage specific interventions to mitigate the existing black-white disparity in young adults' physical health.

Romantic Relationship Commitment Behavior Among Emerging Adult African American Men

Contextual and intrapersonal factors affecting the development of African American men's romantic relationship commitment-related behavior were investigated. Socioeconomic disadvantage during early adolescence was hypothesized to predict harsh, unsupportive parenting practices. Harsh parenting was hypothesized to result in youths' emotion-regulation difficulties, indicated by elevated levels of anger during mid-adolescence, particularly when men were exposed to racial discrimination. Young African American men's anger during mid-adolescence, a consequence of harsh, unsupportive parenting and racial discrimination, was expected to predict commitment-related behavior. Hypotheses were tested with a sample of rural African American men participating in a panel study from the ages of 11 through 21. Data from teachers, parents, and youths were integrated into a multi-reporter measurement plan. Results confirmed the hypothesized associations. Study findings indicate that the combination of harsh parenting and racial discrimination is a powerful antecedent of young men's commitment-related behavior. Anger across mid-adolescence mediated this interaction effect.

Youth temperament, harsh parenting, and variation in the oxytocin receptor gene forecast allostatic load during emerging adulthood

An association has been found between receipt of harsh parenting in childhood and adult health problems. However, this research has been principally retrospective, has treated children as passive recipients of parental behavior, and has overlooked individual differences in youth responsivity to harsh parenting. In a 10-year multiple-wave prospective study of African American families, we addressed these issues by focusing on the influence of polymorphisms in the oxytocin receptor gene (OXTR), variants of which appear to buffer or amplify responses to environmental stress. The participants were 303 youths, with a mean age of 11.2 at the first assessment, and their parents, all of whom were genotyped for variations in the rs53576 (A/G) polymorphism. Teachers rated preadolescent (ages 11 to 13) emotionally intense and distractible temperaments, and adolescents (ages 15 and 16) reported receipt of harsh parenting. Allostatic load was assessed during young adulthood (ages 20 and 21). Difficult preadolescent temperament forecast elevated receipt of harsh parenting in adolescence, and adolescents who experienced harsh parenting evinced high allostatic load during young adulthood. However, these associations emerged only among children and parents who carried A alleles of the OXTR genotype. The results suggest the oxytocin system operates along with temperament and parenting to forecast young adults' allostatic load.

Sociodemographic, behavioral and genetic determinants of allostatic load in a Swiss population-based study

Allostatic load (AL) is a marker of physiological dysregulation which reflects exposure to chronic stress. High AL has been related to poorer health outcomes including mortality. We examine here the association of socioeconomic and lifestyle factors with AL. Additionally, we investigate the extent to which AL is genetically determined. We included 803 participants (52% women, mean age 48±16years) from a population and family-based Swiss study. We computed an AL index aggregating 14 markers from cardiovascular, metabolic, lipidic, oxidative, hypothalamus-pituitary-adrenal and inflammatory homeostatic axes. Education and occupational position were used as indicators of socioeconomic status. Marital status, stress, alcohol intake, smoking, dietary patterns and physical activity were considered as lifestyle factors. Heritability of AL was estimated by maximum likelihood. Women with a low occupational position had higher AL (low vs. high OR=3.99, 95%CI [1.22;13.05]), while the opposite was observed for men (middle vs. high OR=0.48, 95%CI [0.23;0.99]). Education tended to be inversely associated with AL in both sexes(low vs. high OR=3.54, 95%CI [1.69;7.4]/OR=1.59, 95%CI [0.88;2.90] in women/men). Heavy drinking men as well as women abstaining from alcohol had higher AL than moderate drinkers. Physical activity was protective against AL while high salt intake was related to increased AL risk. The heritability of AL was estimated to be 29.5% ±7.9%. Our results suggest that generalized physiological dysregulation, as measured by AL, is determined by both environmental and genetic factors. The genetic contribution to AL remains modest when compared to the environmental component, which explains approximately 70% of the phenotypic variance.

The Great Recession and health risks in African American youth

In the present study, we investigated associations of macro-economic conditions - the Great Recession - with cellular epigenetic aging, allostatic load, and self-reported health, in a group that experiences significant health disparities, African Americans. A sample of 330 African American adolescents in Georgia was followed from pre-recession (2007, M age=16.6) to post-recession (2010, M age=19.3). Economic data were collected in both 2007 and 2010. Three groups were formed to represent economic trajectories across the period of the Great Recession (stable low economic hardship, downward mobility, and stable high economic hardship). At age 19, measures of cellular epigenetic aging (derived from leukocyte DNA methylation profiles, reflecting the disparity between a person's biological and chronological age), allostatic load (composite of blood pressure, C reactive protein, cortisol, epinephrine, norepinephrine, and body mass index), and adolescent self-report of health were obtained. Linear trend analyses documented significant differences across all outcomes. The more time adolescents spent under economic hardship, the higher their epigenetic aging [estimate=1.421, SE=0.466, p=.002] and allostatic load [estimate=1.151, SE=0.375, p=.002] scores, and the worse their self-report of health [estimate=4.957, SE=1.800, p=.006]. Specific group comparisons revealed that adolescents in the downward mobility group had higher levels of allostatic load than adolescents in the stable low hardship group [p<.05]. Overall, these findings suggest that the health profiles of African American youth may in part be shaped by environmental macro-economic societal conditions, and that effects on biological markers can be detected relatively early in life.

Supportive Family Environments Ameliorate the Link Between Racial Discrimination and Epigenetic Aging: A Replication Across Two Longitudinal Cohorts

This study tested the hypothesis that supportive family environments during adolescence buffer exposure to racial discrimination, reducing its impact on biological weathering and its manifestation in cellular aging. Perceived racial discrimination, support in the family environment, and confounder variables were assessed for 3 consecutive years across adolescence in two independent cohorts of African American youth from rural Georgia. DNA was extracted from peripheral blood mononuclear cells collected during young adulthood. Patterns of methylation were used to index the epigenetic ages of these cells and the extent to which they differed from participants' chronological ages. Among youth in supportive family environments, exposure to higher levels of racial discrimination did not forecast greater epigenetic aging. Among youth in less supportive family environments, exposure to higher levels of racial discrimination did forecast greater epigenetic aging. The associations emerged independently of confounder variables, and the results were replicated across the two cohorts.

Variation in the oxytocin receptor gene moderates the protective effects of a family-based prevention program on telomere length

INTRODUCTION

Parent-child relationships with high conflict and low warmth and support are associated with later adverse behavioral and physiological child outcomes. These outcomes include shorter telomere lengths, the repetitive sequences at the ends of chromosomes that have been utilized as a biomarker for chronic stress. Our research group furthered this by exploring telomere length outcomes following a family-based prevention program and identified reduced telomere shortening 5 years post intervention among those originally exposed to nonsupportive parenting and randomized to the intervention condition. However, not all individuals respond equally, and a growing literature suggests genetic sensitivity to one's environment, with variations in the oxytocin receptor gene (OXTR) potentially influencing this sensitivity.

METHODS

We utilized data from African American youths (mean age 17) randomized to intervention (n = 100) or control condition (n = 91) with baseline assessments of genetic status and nonsupportive parenting, and 5-year follow-up assessments of telomere length.

RESULTS

We found a significant three-way interaction between nonsupportive parenting, intervention condition, and OXTR rs53576 genotype. OXTR GG individuals, who are suggested to be more sensitive to their social environment, exhibited significantly more variability, evidencing the shortest telomeres when exposed to nonsupportive parenting and randomized to the control condition, and similar telomere lengths to non at-risk groups when randomized to the intervention. In contrast, those with the A allele showed no statistical difference in telomere lengths across parental and intervention conditions. Subsequent analyses suggest that these findings may be mediated through chronic anger, whereby GG individuals exposed to nonsupportive parenting and randomized to the control condition had a greater increase in chronic anger by study follow-up, compared to those in the intervention, and this change associated with greater telomere shortening.

CONCLUSIONS

These findings highlight the importance of individual differences and potential role of genetic status in moderating the relationship between environmental contexts and biological outcomes.

Prevention effects ameliorate the prospective association between nonsupportive parenting and diminished telomere length

Telomere length (TL) is an indicator of general systemic aging, with diminished TL associated with several chronic diseases of aging and with heightened mortality risk. Research has begun to focus on the ways in which stress contributes to telomere attrition. The purposes of this study were (a) to establish whether exposure to nonsupportive parenting, defined as high levels of conflict and rancor with low levels of warmth and emotional support, at age 17 would forecast TL 5 years later; and (b) to determine whether participation in an efficacious family-centered prevention program could ameliorate any associations that emerged. Rural African American adolescents participated in the Adults in the Making (AIM) program or a control condition. Primary caregivers provided data on nonsupportive parenting during a pretest when adolescents were age 17. Adolescents provided data on anger at the pretest and at a posttest administered 7 months later. When the youths were age 22, TL was assayed from a blood draw. The results indicated that heightened nonsupportive parenting forecast diminished TL among young adults in the control condition but not among those who participated in AIM; socioeconomic status risk, life stress, and the use of alcohol and cigarettes at age 17, and blood pressure and body mass index at age 22, were controlled. Subsequent exploratory analyses suggested that AIM-induced reductions in adolescents' anger served as a mediator connecting group assignment to TL. The results suggest that the cellular-level sequelae of nonsupportive parenting and stress are not immutable.

Epigenetics of Stress, Addiction, and Resilience: Therapeutic Implications

Substance use disorders (SUDs) are highly prevalent. SUDs involve vicious cycles of binges followed by occasional periods of abstinence with recurrent relapses despite treatment and adverse medical and psychosocial consequences. There is convincing evidence that early and adult stressful life events are risks factors for the development of addiction and serve as cues that trigger relapses. Nevertheless, the fact that not all individuals who face traumatic events develop addiction to licit or illicit drugs suggests the existence of individual and/or familial resilient factors that protect these mentally healthy individuals. Here, I give a brief overview of the epigenetic bases of responses to stressful events and of epigenetic changes associated with the administration of drugs of abuse. I also discuss the psychobiology of resilience and alterations in epigenetic markers that have been observed in models of resilience. Finally, I suggest the possibility that treatment of addiction should involve cognitive and pharmacological approaches that enhance resilience in at risk individuals. Similar approaches should also be used with patients who have already succumbed to the nefarious effects of addictive substances.

Genetic moderation of child maltreatment effects on depression and internalizing symptoms by serotonin transporter linked polymorphic region (5-HTTLPR), brain-derived neurotrophic factor (BDNF), norepinephrine transporter (NET), and corticotropin releasing hormone receptor 1 (CRHR1) genes in African American children

Genetic moderation of the effects of child maltreatment on depression and internalizing symptoms was investigated in a sample of low-income maltreated and nonmaltreated African American children (N = 1,096). Lifetime child maltreatment experiences were independently coded from Child Protective Services records and maternal report. Child depression and internalizing problems were assessed in the context of a summer research camp by self-report on the Children's Depression Inventory and adult counselor report on the Teacher Report Form. DNA was obtained from buccal cell or saliva samples and genotyped for polymorphisms of the following genes: serotonin transporter linked polymorphic region (5-HTTLPR), brain-derived neurotrophic factor (BDNF), norepinephrine transporter, and corticotropin releasing hormone receptor 1. Analyses of covariance with age and gender as covariates were conducted, with maltreatment status and respective polymorphism as main effects and their Gene × Environment (G × E) interactions. Maltreatment consistently was associated with higher Children's Depression Inventory and Teacher Report Form symptoms. The results for child self-report symptoms indicated a G × E interaction for BDNF and maltreatment. In addition, BDNF and triallelic 5-HTTLPR interacted with child maltreatment in a G × G × E interaction. Analyses for counselor report of child anxiety/depression symptoms on the Teacher Report Form indicated moderation of child maltreatment effects by triallelic 5-HTTLPR. These effects were elaborated based on variation in developmental timing of maltreatment experiences. Norepinephrine transporter was found to further moderate the G × E interaction of 5-HTTLPR and maltreatment status, revealing a G × G × E interaction. This G × G × E was extended by consideration of variation in maltreatment subtype experiences. Finally, G × G × E effects were observed for the co-action of BDNF and the corticotropin releasing hormone receptor 1 haplotype. The findings illustrate the variable influence of specific genotypes in G × E interactions based on variation in maltreatment experiences and the importance of a multigenic approach for understanding influences on depression and internalizing symptoms among African American children.

Family Economic Hardship, Corticotropin-Releasing Hormone Receptor Polymorphisms, and Depressive Symptoms in Rural African-American Youths

PURPOSE

The purpose of this study was to use pooled data from two independent studies of rural African-American youths to test the moderation effect of the corticotropin-releasing hormone receptor 1 gene (CRHR1) on the link between family economic hardship and trajectories of depressive symptoms.

METHODS

Two longitudinal studies were conducted involving African-Americans, aged 16 (N = 474) and 18 (N = 419) years, who were randomly recruited in rural Georgia. Family economic hardship and youths' depressive symptoms were assessed four times across 2.5 years. Genetic data also were collected. Haplotype analysis was performed on single-nucleotide polymorphisms of CRHR1; two haplotypes were aggregated to form a CRHR1 index. Growth curve models were executed to determine whether CRHR1 moderated the link between Wave 1 family economic hardship and youths' development of depression.

RESULTS

CRHR1 × family economic hardship interactions significantly predicted youths' depressive symptoms. When exposed to family economic hardship 1 standard deviation above the mean at Wave 1, youths who scored 0 on the CRHR1 index showed high and increasing depressive symptoms across time, whereas those who scored 2 on the index showed a decrease in depressive symptoms.

CONCLUSIONS

The CRHR1 gene reduces the risk for depressive symptoms among youths living in families undergoing high levels of economic hardship.

Parent and youth dopamine D4 receptor genotypes moderate multilevel contextual effects on rural African American youth's risk behavior

The present investigation extends research on Gene × Environment interactions and youth risk behavior by linking multilevel contextual factors, such as community disadvantage and protective parenting practices, to both parental and youth dopamine D4 receptor (DRD4) genotypes. We expected community disadvantage to influence youth risk behavior via a series of indirect effects involving protective parenting and youth's planful future orientation when both parents' and youth's DRD4 status was considered. Genetic moderation processes also were tested to determine whether they conformed to a diathesis-stress or a differential susceptibility model. Hypotheses were investigated with data from 361 rural African American youth and their parents assessed 3 times when youth were ages 16 to 19. Community disadvantage interacted with parental DRD4 status to predict low levels of protective parenting. Protective parenting, in turn, interacted with youth DRD4 status to forecast increases in youth's planful future orientations, a proximal influence on changes in risk behavior. The Parental DRD4 × Community Disadvantage interaction, but not youth DRD4 × Protective Parenting, conformed to a differential susceptibility model. Indirect effect analyses revealed a significant indirect path linking community disadvantage to youth risk behavior through a series of multilevel Gene × Environment interaction processes.

Resilience as Regulation of Developmental and Family Processes

Resilience can be defined as establishing equilibrium subsequent to disturbances to a system caused by significant adversity. When families experience adversity or transitions, multiple regulatory processes may be involved in establishing equilibrium, including adaptability, regulation of negative affect, and effective problem-solving skills. The authors' resilience-as-regulation perspective integrates insights about the regulation of individual development with processes that regulate family systems. This middle-range theory of family resilience focuses on regulatory processes across levels that are involved in adaptation: whole-family systems such as routines and sense of coherence; coregulation of dyads involving emotion regulation, structuring, and reciprocal influences between social partners; and individual self-regulation. Insights about resilience-as-regulation are then applied to family-strengthening interventions that are designed to promote adaptation to adversity. Unresolved issues are discussed in relation to resilience-as-regulation in families, in particular how risk exposure is assessed, interrelations among family regulatory mechanisms, and how families scaffold the development of children's resilience.

Stress and resource pathways connecting early socioeconomic adversity to young adults' physical health risk

Although research has established the impact of early stress, including stressful life contexts, and early resources, such as educational attainment, on various adolescent health outcomes, previous research has not adequately investigated "integrative models" incorporating both stress and resource mediational pathways to explain how early socioeconomic adversity impacts physical health outcomes, particularly in early life stages. Data on early childhood/adolescent stress and socioeconomic resources as well as biomarkers indicating physical health status in young adulthood were collected from 11,798 respondents (54 % female) over a 13-year period from youth participating in the National Study of Adolescent Health (Add Health). Physical health risk in young adulthood was measured using a composite index of nine regulatory biomarkers of cardiovascular and metabolic systems. Heterogeneity in stress and socioeconomic resource pathways was assessed using latent class analysis to identify clusters, or classes, of stress and socioeconomic resource trajectories. The influence of early socioeconomic adversity on young adults' physical health risk, as measured by biomarkers, was estimated, and the role of stress and socioeconomic resource trajectory classes as linking mechanisms was assessed. There was evidence for the influence of early socioeconomic adversity on young adults' physical health risk directly and indirectly through stress and socioeconomic resource trajectory classes over the early life course. These findings suggest that health models should be broadened to incorporate both stress and resource experiences simultaneously. Furthermore, these findings have prevention and intervention implications, including the importance of early socioeconomic adversity and key intervention points for "turning" the trajectories of at-risk youth.

Neighborhood poverty and allostatic load in African American youth

OBJECTIVE

This study was designed to determine whether living in a neighborhood in which poverty levels increase across adolescence is associated with heightened levels of allostatic load (AL), a biological composite reflecting cardiometabolic risk. The researchers also sought to determine whether receipt of emotional support could ameliorate the effects of increases in neighborhood poverty on AL.

METHODS

Neighborhood concentrations of poverty were obtained from the Census Bureau for 420 African American youth living in rural Georgia when they were 11 and 19 years of age. AL was measured at age 19 by using established protocols for children and adolescents. When youth were 18, caregivers reported parental emotional support and youth assessed receipt of peer and mentor emotional support. Covariates included family poverty status at ages 11 and 19, family financial stress, parental employment status, youth stress, and youths' unhealthful behaviors.

RESULTS

Youth who lived in neighborhoods in which poverty levels increased from ages 11 to 19 evinced the highest levels of AL even after accounting for the individual-level covariates. The association of increasing neighborhood poverty across adolescence with AL was not significant for youth who received high emotional support.

CONCLUSIONS

This study is the first to show an association between AL and residence in a neighborhood that increases in poverty. It also highlights the benefits of supportive relationships in ameliorating this association.

Neighborhood Poverty, College Attendance, and Diverging Profiles of Substance Use and Allostatic Load in Rural African American Youth

A subset of African American youth who live in impoverished neighborhoods display resilient profiles academically and behaviorally. We hypothesized that this resilience might be "skin-deep," in that the ongoing efforts needed to achieve success might take a physiological toll on these youth. At age 19, 452 rural African American youth were assessed on broader contextual risk (neighborhood poverty) and external indicators of success (college attendance). One year later, participants were assessed on substance use and cumulative physiological risk (allostatic load). African American youth from more disadvantaged neighborhoods who attended college had lower levels of substance use, but higher levels of allostatic load compared to those from less disadvantaged neighborhoods who attended college, or to those who did not attend college. These findings indicate that a subset of African American youth from poor neighborhoods exhibits a profile of "skin-deep resilience," characterized by external successes combined with heightened internal physiological risk.

How an online intervention to prevent excessive gestational weight gain is used and by whom: a randomized controlled process evaluation

BACKGROUND

Online interventions have emerged as a popular strategy to promote healthy behaviors. Currently, there is little agreement about how to capture online intervention engagement. It is also uncertain who engages with weight-related online interventions and how engagement differs by demographic and weight characteristics.

OBJECTIVE

The objectives of this study were to (1) characterize how pregnant women engaged with features of an online intervention to prevent excessive gestational weight gain, (2) identify demographic and weight status subgroups of women within the sample, and (3) examine differences in use of intervention features across the demographic and weight status subgroups.

METHODS

A sample of racially and socioeconomically diverse pregnant women from a northeastern US city was assigned to the intervention group in a randomized controlled trial to prevent excessive gestational weight gain (n=1014). The intervention website included these features: weight-gain tracker, health-related articles, blogs, physical activity and diet goal-setting tools, and local resources. Engagement variables were created to capture the amount, consistency, and patterns of feature use across pregnancy using latent class analysis. Demographic/weight status subgroups were also created using latent class analysis. Differences in engagement across the demographic/weight status subgroups were examined using chi-square analysis.

RESULTS

Six engagement patterns emerged: "super-users" (13.02%, 132/1014), "medium-users" (14.00%, 142/1014), "consistent weight-tracker users" (14.99%, 152/1014); "almost consistent weight-tracker users" (21.99%, 223/1014), "inconsistent weight-tracker users" (15.98%, 162/1014), and "non-users" (20.02%, 203/1014). Four demographic/weight status subgroups emerged: three minority and one white. There were different engagement patterns by demographic/weight status subgroups. Super-users were more likely to be in the white subgroup, while non-users were more likely to be in the minority subgroups. However, around a third of women in minority subgroups were consistently or almost consistently engaging with the weight-tracker (black, young women, 32.2%, 67/208; black, heavier women, 37.9%, 50/132; Hispanic women, 27.4%, 32/117).

CONCLUSIONS

While white and higher income women had higher engagement in general, depending on the measure, there was still considerable engagement by the minority and low-income women.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01331564; http://clinicaltrials.gov/ct2/show/NCT01331564 (Archived by WebCite at http://www.webcitation.org/6Rw4yKxI5).

Catecholamine levels and delay discounting forecast drug use among African American youths

AIMS

To test hypotheses about the contributions of the catecholamines epinephrine and norepinephrine [which serve as biological markers of life stress through sympathetic nervous system (SNS) activation], delay discounting and their interaction to the prediction of drug use among young African American adults.

DESIGN

A 1-year prospective study that involved assessment of SNS activity and collection of self-report data involving delay discounting and drug use.

SETTING

Rural communities in the southeastern United States.

PARTICIPANTS

A total of 456 African Americans who were 19 years of age at the beginning of the study.

MEASUREMENTS

At age 19, participants provided overnight urine voids that were assayed for epinephrine and norepinephrine. Participants were also assessed for hyperbolic temporal discounting functions (k) and drug use. At age 20, the participants again reported their drug use.

FINDINGS

Linear regression analyses revealed that (i) catecholamine levels at age 19 forecast increases in drug use [B = 0.087, P < 0.01, 95% confidence interval (CI) = 0.025, 0.148] and (ii) among young men, catecholamine levels interacted positively with delay discounting to forecast increases in drug use (simple slope = 0.113, P < 0.001, 95% CI = 0.074, 0.152).

CONCLUSIONS

Higher urinary catecholamine concentrations in their adulthood predict higher levels of drug use a year later among young African American men in the United States who engage in high, but not low, levels of delay discounting.

Perceived discrimination among African American adolescents and allostatic load: a longitudinal analysis with buffering effects

This study was designed to examine the prospective relations of perceived racial discrimination with allostatic load (AL), along with a possible buffer of the association. A sample of 331 African Americans in the rural South provided assessments of perceived discrimination from ages 16 to 18 years. When youth were 18 years, caregivers reported parental emotional support and youth assessed peer emotional support. AL and potential confounder variables were assessed when youth were 20. Latent growth mixture modeling identified two perceived discrimination classes: high and stable, and low and increasing. Adolescents in the high and stable class evinced heightened AL even with confounder variables controlled. The racial discrimination to AL link was not significant for young adults who received high emotional support.

Are stressful developmental processes of youths leading to health problems amplified by genetic polymorphisms? The case of body mass index

Although previous research has documented the adverse influence of early socioeconomic disadvantage on youths' physical health outcomes and the increase in health inequalities over the early life course, little is known about genetically informed sequential life course developmental processes leading to health outcomes. Consistent with the life course-stress process perspective, we hypothesized that early socioeconomic adversity initiates a stress process over the early life course. This process involves the disrupted transition from adolescence to young adulthood, which increases the risk of health problems during young adulthood. Behavioral, psychosocial, and genetic data were collected from 12,424 adolescents (53 % female) over a period of 13 years participating in the nationally representative National Longitudinal Study of Adolescent Health (Add Health). Early cumulative socioeconomic adversity and the polygenic influence were measured using composite indices. The study provided evidence for stressful developmental processes of adolescents, involving parental rejection, depressive symptoms, and adolescents' precocious transition. This longitudinal process was initiated by early cumulative socioeconomic adversity and eventuated with young adults' increased body mass index (BMI). Furthermore, the study provided evidence for the influence of life context-gene interactions (G × E) on adolescents' precocious development and young adult BMI (after controlling for the lagged measure) amplifying the stress process over the early life course. These findings emphasize the need for incorporating individual genetic characteristics in a longitudinal context into life course stress research. Furthermore, policies focused on eradicating childhood/adolescent adversities are necessary as well as youth programs and policies that promote youth competencies that aid in their successful transition to young adulthood.

The long arm of adolescence: school health behavioral environments, tobacco and alcohol co-use, and the 5HTTLPR gene

Although sociologists, demographers, and others have thoroughly studied contextual and life course influences on tobacco and alcohol use in adolescence and young adulthood, far less attention has been paid to the determinants of tobacco and alcohol co-use. This is important to remedy because co-use has a nonadditive effect on long-term health. In this article, we use nationally representative, longitudinal data from adolescents and young adults to examine patterns of joint tobacco and alcohol use behaviors across the life course. Importantly, we describe how these trajectories are linked to respondents' high school's joint profile of tobacco and alcohol use, measured two ways: as the proportion of tobacco and alcohol co-users, and as the "excess proportion" above that expected based on the marginal probabilities of smoking and drinking in that school. Joint tobacco and alcohol use is associated with both measures, emphasizing the "long arm" of adolescent contexts. Furthermore, we extend previous research to assess whether there is a gene-environment interaction between this school-level measure, 5HTTLPR, and tobacco and alcohol co-use, as suggested by recent work analyzing drinking and smoking separately. We find evidence of such a pattern but conclude that it is likely to be due to population stratification or other forms of confounding.

Is resilience only skin deep?: rural African Americans' socioeconomic status-related risk and competence in preadolescence and psychological adjustment and allostatic load at age 19

Many African American youth may develop high levels of allostatic load, a measure of physiological wear and tear on the body, by developing psychosocial competence under conditions of high risk related to socioeconomic status (SES). The current study was designed to test this hypothesis, which is based on John Henryism theory. In a representative sample of 489 African American youth living in the rural South, cumulative SES-related risks and teacher-reported competence were assessed at ages 11 to 13; depressive symptoms, externalizing behavior, and allostatic load were assessed at age 19. The data revealed that rural African American preadolescents who evinced high psychosocial competence under conditions of high cumulative SES-related risk displayed low levels of adjustment problems along with high allostatic load at age 19. These results suggest that, for many rural African Americans, resilience may indeed be only "skin deep."

Life stress, the dopamine receptor gene, and emerging adult drug use trajectories: a longitudinal, multilevel, mediated moderation analysis

This study was designed to examine the prospective relations of life stress and genetic status with increases in drug use. African Americans (N = 399) in rural Georgia (Wave 1 mean age = 17 years) provided three waves of data across 27.5 months and a saliva sample from which the dopamine receptor D4 (DRD4) gene was genotyped. Multilevel growth curve modeling analysis indicated that emerging adults manifested the highest escalations in drug use when they reported high life stress and carried an allele of DRD4 with 7 or more repeats (7 + R allele). In addition, emerging adults who reported high life stress and carried the 7 + R allele evinced the largest increases in two proximal risk factors for drug use: affiliations with drug-using companions and drug use vulnerability cognitions. Furthermore, when the Gene × Environment interaction effects on the increases in affiliations with drug-using companions and vulnerability cognitions were entered into the model forecasting drug use, the Life Stress × DRD4 Status interaction on drug use became nonsignificant in the presence of the risk mechanisms. This finding provides an example of "second generation" Gene × Environment interaction research in which the interaction's effects on proximal risk mechanisms account for its effects on outcomes.