Social, behavioral, and genetic linkages from adolescence into adulthood

Estimating Transition Probabilities for Modeling Major Depression in Adolescents by Sex and Race or Ethnicity Combinations in the USA

OBJECTIVE

About one-fifth of US adolescents experienced major depressive symptoms, but few studies have examined longitudinal trends of adolescents developing depression or recovering by demographic factors. We estimated new transition probability inputs, and then used them in a simulation model to project the epidemiologic burden and trajectory of depression of diverse adolescents by sex and race or ethnicity combinations.

METHODS

Transition probabilities were first derived using parametric survival analysis of data from the National Longitudinal Study of Adolescent to Adult Health and then calibrated to cross-sectional data from the National Survey on Drug Use and Health. We developed a cohort state-transition model to simulate age-specific depression outcomes of US adolescents. A hypothetical adolescent cohort was modeled from 12-22 years with annual transitions. Model outcomes included proportions of youth experiencing depression, recovery, or depression-free cases and were reported for a US adolescent population by sex, race or ethnicity, and sex and race or ethnicity combinations.

RESULTS

At 22 years of age, approximately 16% of adolescents had depression, 12% were in recovery, and 72% had never developed depression. Depression prevalence peaked around 16-17 years-old. Adolescents of multiracial or other race or ethnicity, White, American Indian or Alaska Native, and Hispanic, Latino, or Spanish descent were more likely to experience depression than other racial or ethnic groups. Depression trajectories generated by the model matched well with historical observational studies by sex and race or ethnicity, except for individuals from American Indian or Alaska Native and multiracial or other race or ethnicity backgrounds.

CONCLUSIONS

This study validated new transition probabilities for future use in decision models evaluating adolescent depression policies or interventions. Different sets of transition parameters by demographic factors (sex and race or ethnicity combinations) were generated to support future health equity research, including distributional cost-effectiveness analysis. Further data disaggregated with respect to race, ethnicity, religion, income, geography, gender identity, sexual orientation, and disability would be helpful to project accurate estimates for historically minoritized communities.

Sociolocation: A Proposed Conceptual Element in Lifespan Development

Individual identity as a function of human development significantly intersects with and is necessarily influenced by the social world. To describe this intersection and its effects, the term sociolocation was proposed, initially in the context of adolescent development, and defined as "self-identification and recognition of social integration through relationships." Almost a decade later, it is apparent that the processes of sociolocation may continue and repeat through the rest of the lifespan. The purpose of this, therefore, paper is to present an expanded definitional and conceptual analysis of sociolocation using the techniques described by Chinn, Kramer, and Sitzman. Such an analysis is important across nursing science, practice, and education, since in all three domains the nurse may encounter individuals engaged in sociolocation. Understanding what this process is and when and how it may occur can be helpful in care planning, learning, and research endeavors.

Polygenic Propensity for Longevity, APOE-ε4 Status, Dementia Diagnosis, and Risk for Cause-Specific Mortality: A Large Population-Based Longitudinal Study of Older Adults

To deepen the understanding of genetic mechanisms influencing mortality risk, we investigated the impact of genetic predisposition to longevity and APOE-ε4, on all-cause mortality and specific causes of mortality. We further investigated the mediating effects of dementia on these relationships. Using data on 7 131 adults aged ≥50 years (mean = 64.7 years, standard deviation [SD] = 9.5) from the English Longitudinal Study of Aging, genetic predisposition to longevity was calculated using the polygenic score approach (PGSlongevity). APOE-ε4 status was defined according to the absence or presence of ε4 alleles. The causes of death were ascertained from the National Health Service central register, which was classified into cardiovascular diseases, cancers, respiratory illness, and all other causes of mortality. Of the entire sample, 1 234 (17.3%) died during an average 10-year follow-up. One-SD increase in PGSlongevity was associated with a reduced risk for all-cause mortality (hazard ratio [HR] = 0.93, 95% confidence interval [CI]: 0.88-0.98, p = .010) and mortalities due to other causes (HR = 0.81, 95% CI: 0.71-0.93, p = .002) in the following 10 years. In gender-stratified analyses, APOE-ε4 status was associated with a reduced risk for all-cause mortality and mortalities related to cancers in women. Mediation analyses estimated that the percent excess risk of APOE-ε4 on other causes of mortality risk explained by the dementia diagnosis was 24%, which increased to 34% when the sample was restricted to adults who were aged ≤75 years old. To reduce the mortality rate in adults who are aged ≥50 years old, it is essential to prevent dementia onset in the general population.

Long-term air pollution exposure and markers of cardiometabolic health in the National Longitudinal Study of Adolescent to Adult Health (Add Health)

BACKGROUND

Air pollution exposure is associated with cardiovascular morbidity and mortality. Although exposure to air pollution early in life may represent a critical window for development of cardiovascular disease risk factors, few studies have examined associations of long-term air pollution exposure with markers of cardiovascular and metabolic health in young adults.

OBJECTIVES

By combining health data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) with air pollution data from the Fused Air Quality Surface using Downscaling (FAQSD) archive, we: (1) calculated multi-year estimates of exposure to ozone (O3) and particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM2.5) for Add Health participants; and (2) estimated associations between air pollution exposures and multiple markers of cardiometabolic health.

METHODS

Add Health is a nationally representative longitudinal cohort study of over 20,000 adolescents aged 12-19 in the United States (US) in 1994-95 (Wave I). Participants have been followed through adolescence and into adulthood with five in-home interviews. Estimated daily concentrations of O3 and PM2.5 at census tracts were obtained from the FAQSD archive and used to generate tract-level annual averages of O3 and PM2.5 concentrations. We estimated associations between average O3 and PM2.5 exposures from 2002 to 2007 and markers of cardiometabolic health measured at Wave IV (2008-09), including hypertension, hyperlipidemia, body mass index (BMI), diabetes, C-reactive protein, and metabolic syndrome.

RESULTS

The final sample size was 11,259 individual participants. The average age of participants at Wave IV was 28.4 years (range: 24-34 years). In models adjusting for age, race/ethnicity, and sex, long-term O3 exposure (2002-07) was associated with elevated odds of hypertension, with an odds ratio (OR) of 1.015 (95% confidence interval [CI]: 1.011, 1.029); obesity (1.022 [1.004, 1.040]); diabetes (1.032 [1.009,1.054]); and metabolic syndrome (1.028 [1.014, 1.041]); PM2.5 exposure (2002-07) was associated with elevated odds of hypertension (1.022 [1.001, 1.045]).

CONCLUSION

Findings suggest that long-term ambient air pollution exposure, particularly O3 exposure, is associated with cardiometabolic health in early adulthood.

From society to cells and back again: new opportunities for discovery at the biosocial interface

A new generation of community- and population-based research is combining measures of social context, experience, and behavior with direct measures of physiology, gene sequence and function, and health. Studies drawing on models and methods from the social and biological sciences have the potential to illuminate the multilevel mechanisms through which experience becomes biology, and to move past decontextualized and reductionistic approaches to human development, behavior, and health. In this perspective we highlight challenges and opportunities at the biosocial interface, and briefly discuss COVID-19 as a case study demonstrating the importance of linking across levels of analysis.

Twenty-Five Years of National-Level Research on Adolescent and Young Adult Mental Health in the United States

The longitudinal, population-level, biosocial data in the National Longitudinal Study of Adolescent to Adult Health (Add Health) have elucidated the developmental course of mental health across early stages of the life course. This data set also has been invaluable for documenting and unpacking disparities in these developmental patterns by race, ethnicity, socioeconomic status, gender, immigration, and sexuality. Reflecting the larger focus of this special supplement on Add Health as a tool for connecting adolescence to adulthood, this article reviews Add Health research since 2000 based on a search of key mental health terms, primarily describing patterns of two key markers of psychopathology (depressive symptoms, suicidal ideation) that were consistently measured across waves. It situates these patterns from adolescence into adulthood within the developmental ecology organized by the proximate settings of everyday life, the larger social structures organized by a highly stratified society, and the relations of these ecological and structural forces to biological processes. Major foci are the dynamic nature of mental health across the life course and the ways that ecological and physiological influences on mental health differ by group identity and social position.

Sibling absence and body mass index: From adolescence to adulthood

OBJECTIVES

To examine if sibling absence is associated with higher BMI and to identify potential lifestyle factors underlying this effect; to determine if sibling effects on BMI persist into adulthood.

METHODS

We used data from all five waves of the National Longitudinal Study of Adolescent to Adult Health to study the sibling factors and BMI of 3,563 participants who were in grades 7-12 at first wave (1994-95). These participants were measured again in the second wave (1996), the third wave (2001-2002), the fourth wave (2008-2009), and most recently, the fifth wave (2016-2018). We identified categories of siblings, comparing the BMI of those without siblings either to birth order or sibship size. BMI was calculated based on direct measurements of height and weight; underlying mechanisms were self-reported.

RESULTS

Participants without siblings had significantly higher BMI than those with siblings, across waves, regardless of sibship size. Those without siblings had consistently higher BMI than middle-born, but not last-born participants. Adolescents without siblings reported eating fast food more frequently and spending more screen time.

CONCLUSIONS

Sibling absence is associated with higher BMI in adolescence and this difference persists into adulthood.

Mothers' Out-of-Sequence Postsecondary Education and Their Health and Health Behaviors

Ample research suggests that the links between higher education and heath are robust and growing in strength. This research, however, tends to assume education was completed prior to assuming other adult roles. Importantly, the life course framework raises the question of whether "out-of-sequence" college completion conveys similar health returns. I investigate this question among a population for whom out-of-sequence schooling has grown more common: lower-educated mothers. This focus is also important given the growing education gap in women's health and the links between maternal and child health. Data come from the Fragile Families and Child Wellbeing Study (N = 4,898). Analyses involve random intercept and fixed effects models and diverse health measures. Findings suggest that postsecondary education does not improve mother's health, except for reduced smoking among mothers with high school degrees or less that earned bachelor's degrees. These findings inform health policy debates and theories linking education to health.

Race/Ethnicity, Gender, and Trajectories of Depressive Symptoms Across Early- and Mid-Life Among the Add Health Cohort

While disparities in depressive symptoms by race/ethnicity and gender have been documented, left unclear is how such status characteristics intersect to influence mental health, particularly across early life and among a diverse set of population subgroups. This study investigates how intra- and inter-individual trends in depressive symptoms unfold across a 30-year span (ages 12-42) and are structured by the intersection of race/ethnicity and gender among White, Black, Hispanic, and Asian American young adults (N = 18,566). Analyses use data from the National Longitudinal Study of Adolescent to Adult Health, a nationally representative study of adolescents who have been followed through their fourth decade of life. We draw on Waves I-IV and a representative subsample of the brand new Wave V data. Growth curve models indicated depressive symptoms decreased across adolescence and young adulthood before increasing in the early 30s. Racial/ethnic minorities reported more depressive symptoms than Whites. Women reported more depressive symptoms than men and experienced especially steep increases in their late 30s. Racial/ethnic-gender disparities remained stable with age, except for Hispanic-White disparities among women and Asian American-White disparities among men, which narrowed with age. Overall, findings demonstrate dynamic inequalities across a longer period of the life span than was previously known, as well as heterogeneity in trajectories of poor mental health within and between racial/ethnic-gender groups. Results also suggest that Black and Asian American women experience the highest mental health risks and that interventions for reducing disparities in depressive symptoms should focus on adults in their late 20s/early 30s, particularly women of color.

The Depths of Despair Among US Adults Entering Midlife

OBJECTIVES

To test whether indicators of despair are rising among US adults as they age toward midlife and whether this rise is concentrated among low-educated Whites and in rural areas.

METHODS

We used data from the National Longitudinal Study of Adolescent to Adult Health, a nationally representative study of US adolescents in 1994. Our sample was restricted to individuals who participated in 1 or more of 5 waves (1994-2017) and self-identified as non-Hispanic White, non-Hispanic Black, or Hispanic (n = 18 446). We examined change in indicators of despair from adolescence to adulthood using multilevel regression analysis, testing for differences by race/ethnicity, education, and rurality.

RESULTS

We found evidence of rising despair among this cohort over the past decade. This increase was not restricted to low-educated Whites or to rural areas.

CONCLUSIONS

Results suggest that generally rising despair among the young adult cohort now reaching midlife that cuts across racial/ethnic, educational, and geographic groups may presage rising midlife mortality for these subgroups in the next decade.

Association of Positive Family Relationships With Mental Health Trajectories From Adolescence to Midlife

IMPORTANCE

National longitudinal studies that examine the linkages between early family experiences and sex-specific development of depression across the life course are lacking despite the urgent need for interventions in family settings to prevent adult depression.

OBJECTIVE

To examine whether positive adolescent family relationships are associated with reduced depressive symptoms among women and men as they enter midlife.

DESIGN, SETTING, AND PARTICIPANTS

This study analyzed data from the National Longitudinal Study of Adolescent to Adult Health, which used a multistage, stratified school-based design to select a prospective cohort of 20 745 adolescents in grades 7 to 12 from January 3, 1994, to December 26, 1995 (wave 1). Respondents were followed up during 4 additional waves from April 14 to September 9, 1996 (wave 2); April 2, 2001, to May 9, 2002 (wave 3); April 3, 2007, to February 1, 2009 (wave 4); and March 3, 2016, to May 8, 2017 (sample 1, wave 5), when the cohort was aged 32 to 42 years. The study sample of 8952 male adolescents and 9233 female adolescents that were analyzed was a US national representation of all population subgroups by sex, race/ethnicity, socioeconomic status, and geography.

EXPOSURES

Adolescent family cohesion and low parent-child conflict.

MAIN OUTCOMES AND MEASURES

Levels of depressive symptoms (Center for Epidemiologic Studies-Depression Scale [CES-D]) from ages 12 to 42 years were used to estimate propensity score-weighted growth curve models to assess sex differences in trajectories of depression by levels of positive adolescent family relationships.

RESULTS

A total of 18 185 individuals (mean [SD] age at wave 1, 15.42 [0.12] years; 9233 [50.8%] female) participated in the study. Females and males who experienced positive adolescent family relationships had significantly lower levels of depressive symptoms from early adolescence to midlife than did those who experienced less positive adolescent family relationships. For example, depressive symptoms were lower among those with high levels of family cohesion compared with those with low cohesion between 12 (1.26 lower CES-D score; 95% CI, 1.10-1.42) and 40 (0.78 lower CES-D score; 95% CI, 0.50-1.06) years of age among females and between 12 (0.72 lower CES-D score; 95% CI, 0.57-0.86) and 37 (0.21 lower CES-D score; 95% CI, 0.00-0.41) years of age among males. The reduction in depressive symptoms associated with positive adolescent family relationships was greater for females than males during the adolescent and early adulthood years (ie, early 20s) (eg, low-high cohesion difference in mean CES-D score, -1.26 [95% CI, -1.42 to -1.10] for females and -0.72 [95% CI, -0.86 to -0.57] for males at 12 years of age; low-high cohesion difference in mean CES-D score, -0.61 [95% CI, -0.69 to -0.53] for females and -0.40 [95% CI, -0.48 to -0.31] for males at 20 years of age), after which females and males benefited equally from positive adolescent relationships throughout young adulthood to midlife.

CONCLUSIONS AND RELEVANCE

The findings suggest that positive adolescent family relationships are associated with better mental health among females and males from early adolescence to midlife. Interventions in early family life to foster healthy mental development throughout the life course appear to be important.

Effects of the peer metagenomic environment on smoking behavior

Recent scholarship suggests that the genomes of those around us affect our own phenotypes. Much of the empirical evidence for such "metagenomic" effects comes from animal studies, where the socio-genetic environment can be easily manipulated. Among humans, it is more difficult to identify such effects given the nonrandom distribution of genes and environments. Here we leverage the as-if-random distribution of grade-mates' genomes conditional on school-level variation in a nationally representative sample. Specifically, we evaluate whether one's peers' genetic propensity to smoke affects one's own smoking behavior net of one's own genotype. Results show that peer genetic propensity to smoke has a substantial effect on an individual's smoking outcome. This is true not only when the peer group includes direct friends, and therefore where the individual plays an active role in shaping the metagenomic context but also when the peer group includes all grade-mates and thus in cases where the individual does not select the metagenomic environment. We explore these effects further and show that a small minority with high genetic risk to smoke ('bad apples') can greatly affect the smoking behavior of an entire grade. The methodology used in this paper offers a potential solution to many of the challenges inherent in estimating peer effects in nonexperimental settings and can be utilized to study a wide range of outcomes with a genetic basis. On a policy level, our results suggest that efforts to reduce adolescent smoking should take into account metagenomic effects, especially bad apples, within social networks.

Neighborhood disadvantage across the transition from adolescence to adulthood and risk of metabolic syndrome

This study investigates the association between neighborhood disadvantage from adolescence to young adulthood and metabolic syndrome using a life course epidemiology framework. Data from the United States-based National Longitudinal Study of Adolescent to Adult Health (n = 9500) and a structural equation modeling approach were used to test neighborhood disadvantage across adolescence, emerging adulthood, and young adulthood in relation to metabolic syndrome. Adolescent neighborhood disadvantage was directly associated with metabolic syndrome in young adulthood. Evidence supporting an indirect association between adolescent neighborhood disadvantage and adult metabolic syndrome was not supported. Efforts to improve cardiometabolic health may benefit from strategies earlier in life.

Genetics and the geography of health, behaviour and attainment

Young people's life chances can be predicted by characteristics of their neighbourhood¹. Children growing up in disadvantaged neighbourhoods exhibit worse physical and mental health and suffer poorer educational and economic outcomes than children growing up in advantaged neighbourhoods. Increasing recognition that aspects of social inequalities tend, in fact, to be geographical inequalities^2-5 is stimulating research and focusing policy interest on the role of place in shaping health, behaviour and social outcomes. Where neighbourhood effects are causal, neighbourhood-level interventions can be effective. Where neighbourhood effects reflect selection of families with different characteristics into different neighbourhoods, interventions should instead target families or individuals directly. To test how selection may affect different neighbourhood-linked problems, we linked neighbourhood data with genetic, health and social outcome data for >7,000 European-descent UK and US young people in the E-Risk and Add Health studies. We tested selection/concentration of genetic risks for obesity, schizophrenia, teen pregnancy and poor educational outcomes in high-risk neighbourhoods, including genetic analysis of neighbourhood mobility. Findings argue against genetic selection/concentration as an explanation for neighbourhood gradients in obesity and mental health problems. By contrast, modest genetic selection/concentration was evident for teen pregnancy and poor educational outcomes, suggesting that neighbourhood effects for these outcomes should be interpreted with care.

Father Absence and Accelerated Reproductive Development in Non-Hispanic White Women in the United States

Girls who experience father absence in childhood also experience accelerated reproductive development in comparison with peers with present fathers. One hypothesis advanced to explain this empirical pattern is genetic confounding, wherein gene-environment correlation (rGE) causes a spurious relationship between father absence and reproductive timing. We test this hypothesis by constructing polygenic scores for age at menarche and first birth using recently available genome-wide association study results and molecular genetic data on a sample of non-Hispanic white females from the National Longitudinal Study of Adolescent to Adult Health. We find that young women's accelerated menarche polygenic scores are unrelated to their exposure to father absence. In contrast, polygenic scores for earlier age at first birth tend to be higher in young women raised in homes with absent fathers. Nevertheless, father absence and the polygenic scores independently and additively predict reproductive timing. We find no evidence in support of the rGE hypothesis for accelerated menarche and only limited evidence in support of the rGE hypothesis for earlier age at first birth.

Adverse life experiences and risk of unintended pregnancy in adolescence and early adulthood: Implications for toxic stress and reproductive health

Objective

We examined the effects of adverse life experiences (ALEs) on rates of unintended first pregnancy, including differential effects by race/ethnicity and socioeconomic status, among women in a national longitudinal cohort study.

Methods

We drew upon 15-years of data from 8810 adolescent and young adult females in the National Longitudinal Study of Adolescent to Adult Health. Using 40 different ALEs reported across childhood and adolescence, we created an additive ALE index, whereby higher scores indicated greater ALE exposure. We employed Cox proportional hazard models, including models stratified by racial/ethnic and socioeconomic groups, to estimate the effects of ALEs on time to first unintended pregnancy, controlling for time-varying sociodemographic, health and reproductive covariates.

Results

Among all women, a 1-standard deviation increase in ALE scores was associated with an increased rate of unintended first pregnancy (adjusted Hazard Ratio 1.11, 95% Confidence Interval=1.04-1.17). In stratified models, associations between ALE scores and risk of unintended pregnancy varied across racial/ethnic, socioeconomic, and age groups and according to various elevated ALE thresholds. For example, the 1-standard deviation increase in ALE score indicator increased the unintended pregnancy risk for African-American (aHR=1.12, CI=1.01-1.25), Asian (aHR 1.69, CI=1.26-2.26), and White women (aHR=1.12, CI=1.03-1.22), women in the lowest ($0-$19,999; aHR=1.21, CI = 1.03-1.23) and highest (>$75,000; aHR=1.36, CI=1.12-1.66) income categories, and women aged 20-24 (aHR=1.13, CI=1.04-1.24) and >24 years (aHR 1.25, CI=1.06-1.47), but not among the other sociodemographic groups.

Conclusion

ALEs increased the risk of unintended first pregnancy overall, and different levels of exposure impacting the risk of pregnancy differently for different sub-groups of women. Our ongoing research is further investigating the role of stress-associated adversity in shaping reproductive health outcomes and disparities in the United States.

Adolescent Reproductive and Contraceptive Knowledge and Attitudes and Adult Contraceptive Behavior

Objectives Ineffective and inconsistent contraceptive use is common among adults, perhaps due to limited knowledge about reproduction and unfavorable attitudes toward contraception. Knowledge and attitudes are first developed in adolescence. We test whether adolescent knowledge and attitudes have long-term implications for adult contraceptive behavior. Methods Using the National Longitudinal Survey of Adolescent to Adult Health, our analytical sample (n = 6662) consists of those asked sex and contraception questions at Wave I (1995; students aged 15 and older) and who were sexually active and not pregnant at the time of the Wave IV (2007-2008) survey. We examined whether adolescent attitudes toward contraception, knowledge of condoms and reproduction, and confidence in contraceptive knowledge were predictive of adult contraceptive efficacy and consistency using logistic regression. Results In models adjusted for a range of socioeconomic, demographic, and life course factors, favorable attitudes toward contraception in adolescence increased the odds (aOR 1.21, CI 1.08-1.36) of using more effective methods rather than a less effective or no method of contraception in adulthood, as did more accurate condom knowledge (aOR 1.07, CI 1.00-1.14) and more accurate reproductive knowledge (aOR 1.07, CI 1.00-1.13). Adolescents with more favorable attitudes toward contraception also used contraception more consistently as adults (aOR 1.27, CI 1.14-1.43), as did those with more accurate condom knowledge (aOR 1.10, CI 1.03-1.18). Conclusions Attitudes towards contraception and knowledge about condoms and reproduction acquired during adolescence are predictive of adult contraceptive behavior. Results suggest that comprehensive sex education during adolescence could improve effective contraceptive behavior throughout the life course.

Wide educational disparities in young adult cardiovascular health

Widening educational differences in overall health and recent stagnation in cardiovascular disease mortality rates highlight the critical need to describe and understand educational disparities in cardiovascular health (CVH) among U.S. young adults. We use two data sets representative of the U.S. population to examine educational disparities in CVH among young adults (24-34) coming of age in the 21st century: the National Health and Nutrition Examination Survey (2005-2010; N= 689) and the National Longitudinal Study of Adolescent to Adult Health (2007-2008; N=11,200). We employ descriptive statistics and regression analysis. The results show that fewer than one in four young adults had good CVH (at least 5 out of 7 ideal cardiovascular indicators). Young adults who had not attained a college degree demonstrate particularly disadvantaged CVH compared with their college-educated peers. Such educational disparities persist after accounting for a range of confounders, including individuals' genetic propensity to develop coronary artery disease. The results indicate that the CVH of today's young adults is troubling and especially compromised for individuals with lower levels of educational attainment. These results generate substantial concern about the future CVH of the US population, particularly for young adults with a low level of education.

Education, Smoking, and Cohort Change: Forwarding a Multidimensional Theory of the Environmental Moderation of Genetic Effects

We introduce a genetic correlation by environment interaction model [(rG)xE] which allows for social environmental moderation of the genetic relationship between two traits. To empirically demonstrate the significance of the (rG)xE perspective, we use genome wide information from respondents of the Health and Retirement Study (HRS; n = 8,181; birth years 1920-1959) and the National Longitudinal Study of Adolescent to Adult Health (Add Health; n = 4,347; birth years 1974-1983) to examine whether the genetic correlation (rG) between education and smoking has increased over historical time. Genetic correlation estimates (rG_HRS = -0.357; rG_{Add Health} = -0.729) support this hypothesis. Using polygenic scores for educational attainment, we show that this is not due to latent indicators of intellectual capacity, and we highlight the importance of education itself as an explanation of the increasing genetic correlation. Analyses based on contextual variation the milieus of the Add Health respondents corroborate key elements of the birth cohort analyses. We argue that the increasing overlap with respect to genes associated with educational attainment and smoking is a fundamentally social process involving complex process of selection based on observable behaviors that may be linked to genotype.

Theoretical Insights into Preconception Social Conditions and Perinatal Health: The Role of Place and Social Relationships

Recent efforts to explain the stark social and racial disparities in adverse birth outcomes that have persisted for decades in the U.S. have looked beyond prenatal factors, to explore preconception social conditions that may influence perinatal health via dysregulation of physiologic processes. The extant evidence supporting this link however remains limited, both due to a lack of data and theory. To address the latter, this manuscript generates a structured set of theoretical insights that further develop the link between two preconception social conditions - place and social relationships - and perinatal health. The insights propose the following.

PLACE

necessarily encompasses all social contexts to which females are exposed from infancy through young adulthood; encompasses a variety of related exposures that, when possible, should be jointly considered; and may compound the effect of poverty-in childhood, adolescence, or young adulthood-on perinatal health. Social relationships: span relationships from early life through adulthood, and extend to intergenerational associations; often involve (or induce) major changes in the lives of individuals and should be examined with an emphasis on the developmental stage in which the change occurred; and necessarily encompass a lack of social integration, or, social isolation. We also identify potential biological and social-structural mechanisms linking these preconception social conditions to perinatal health, and conclude by identifying promising directions for future research.

Adolescent behavioral and neural reward sensitivity: a test of the differential susceptibility theory

Little is known about the causes of individual differences in reward sensitivity. We investigated gene-environment interactions (GxE) on behavioral and neural measures of reward sensitivity, in light of the differential susceptibility theory. This theory states that individuals carrying plasticity gene variants will be more disadvantaged in negative, but more advantaged in positive environments. Reward responses were assessed during a monetary incentive delay task in 178 participants with and 265 without attention-deficit/hyperactivity disorder (ADHD), from N=261 families. We examined interactions between variants in candidate plasticity genes (DAT1, 5-HTT and DRD4) and social environments (maternal expressed emotion and peer affiliation). HTTLPR short allele carriers showed the least reward speeding when exposed to high positive peer affiliation, but the most when faced with low positive peer affiliation or low maternal warmth. DAT1 10-repeat homozygotes displayed similar GxE patterns toward maternal warmth on general task performance. At the neural level, DRD4 7-repeat carriers showed the least striatal activation during reward anticipation when exposed to high maternal warmth, but the most when exposed to low warmth. Findings were independent of ADHD severity. Our results partially confirm the differential susceptibility theory and indicate the importance of positive social environments in reward sensitivity and general task performance for persons with specific genotypes.

[The first KiGGS follow-up (KiGGS Wave 1): study conduct, sample design, and response]

The "German Health Interview and Examination Survey for Children and Adolescents" (KiGGS) is part of the health monitoring system of the Robert Koch Institute (RKI). Following the KiGGS baseline study (2003 - 06), which comprised interviews and physical examinations of 0- to 17-year-old participants, KiGGS Wave 1 (2009 - 2012) was carried out as a telephone-based survey. In addition to providing longitudinal data, a second essential aim of KiGGS is to regularly provide population-based cross-sectional data on the health situation of children and adolescents aged 0-17 years living in Germany. Therefore, the study population of KiGGS Wave 1 consists of re-invited participants from the baseline study (KiGGS cohort), supplemented by newly invited children aged 0-6 years. The newly invited participants were randomly chosen from local population registries in the 167 baseline sample points. This method was chosen to supplement the sample with younger age groups. This article focuses on the age groups from 0 to 17 years, which are relevant for prevalence estimations among children and adolescents. In total 12,368 children and adolescents took part; among them 4,455 newly invited and 7,913 re-invited participants (response 38.8 and 72.9%, respectively). A comparison of the net sample with the resident German population (0-17 years) regarding particular population characteristics and an analysis of the relationship between the re-participation rate and certain characteristics collected in the baseline study (7-17 years) suggest a mostly unbiased sample. To account for certain aspects of the population and nonresponse, cross-sectional and trend analyses were partially corrected by weighting factors.

From genomes to societies: a holistic view of determinants of human health

Both biological and social sciences have identified contributing factors to human health. However, health outcomes are unlikely to equal a simple sum of these identified factors. This article makes an attempt to put together the information, methods, and technologies that relate to health outcomes from biological, behavioral, and social disciplines. Much of this information was obtained by controlling for the variations of the factors in 'other' disciplines. For example, genetic factors were controlled for in identifying the behavioral determinants of health. Looking forward, better understandings of health outcomes may require exploiting the interactions of health determinants that were identified from different disciplines. We propose the concept of 'systems health' studies, which take health outcomes as the outputs of a system, where the inputs and their interactions from multiple disciplines are considered.