Michigan State University Twin Registry Research Articles

The effects of puberty on associations between mood/personality factors and disordered eating symptoms in girls.

Negative and positive urgency, anxiety, and depressive symptoms are significant factors of disordered eating (DE) symptoms in early adolescence through young adulthood. However, it is unclear how puberty-a critical developmental milestone that is associated with increased risk for DE symptoms-affects the relationship between these factors and DE symptoms, given that the role of pubertal status has rarely been considered in relation to these associations. Thus, the present study examined whether puberty moderates associations between mood/personality factors and DE in pre-adolescent and adolescent girls. Participants included 981 girls (aged 8-16 years) from the Michigan State University Twin Registry. Mood/personality factors, pubertal status, and DE were assessed with self-report questionnaires. Puberty significantly moderated associations between several factors (negative urgency, positive urgency, trait anxiety, depressive symptoms) and the cognitive symptoms of DE (e.g., shape/weight concerns, body dissatisfaction). Associations between mood/personality factors and cognitive DE were stronger in girls with more advanced pubertal status. By contrast, no significant moderation effects were detected for mood/personality-dysregulated eating (e.g., binge eating, emotional eating) associations. Findings identify pubertal development as an important moderator of mood/personality-DE symptom associations, especially for cognitive DE symptoms that are known to predict the later onset of clinical pathology.

Continuity and Change in the Genetic and Environmental Etiology of Youth Antisocial Behavior.

Trajectories of youth antisocial behavior (ASB) are characterized by both continuity and change. Twin studies have further indicated that genetic factors underlie continuity, while environmental exposures unique to each child in a given family underlie change. However, most behavioral genetic studies have examined continuity and change during relatively brief windows of development (e.g., during childhood but not into adolescence). It is unclear whether these findings would persist when ASB trajectories are examined across multiple stages of early development (i.e., from early childhood into emerging adulthood). Our study sought to fill this gap by examining participants assessed up to five times between the ages of 3 and 22years using an accelerated longitudinal design in the Michigan State University Twin Registry (MSUTR). We specifically examined the etiologies of stability and change via growth curve modeling and a series of univariate and bivariate twin analyses. While participants exhibited moderate-to-high rank-order stability, mean levels of ASB decreased linearly with age. Genetic and nonshared environmental influences that were present in early childhood also contributed to both stability and change across development, while shared environmental contributions were negligible. In addition, genetic and nonshared environmental influences that were not yet present at the initial assessment contributed to change over time. Although ASB tended to decrease in frequency with age, participants who engaged in high levels of ASB during childhood generally continued to do so throughout development. Moreover, the genetic and nonshared environmental contributions to ASB early in development also shaped the magnitude of the decrease with age.

Twin Differences in Harsh Parenting Predict Youth’s Antisocial Behavior

In the current study, we leveraged differences within twin pairs to examine whether harsh parenting is associated with children’s antisocial behavior via environmental (vs. genetic) transmission. We examined two independent samples from the Michigan State University Twin Registry. Our primary sample contained 1,030 families (2,060 twin children; 49% female; 6–10 years old) oversampled for exposure to disadvantage. Our replication sample included 240 families (480 twin children; 50% female; 6–15 years old). Co-twin control analyses were conducted using a specification-curve framework, an exhaustive modeling approach in which all reasonable analytic specifications of the data are interrogated. Results revealed that, regardless of zygosity, the twin experiencing harsher parenting exhibited more antisocial behavior. These effects were robust across multiple operationalizations and informant reports of both harsh parenting and antisocial behavior with only a few exceptions. Results indicate that the association between harsh parenting and children’s antisocial behavior is, to a large degree, environmental in origin.

Biomarker discovery in attention deficit hyperactivity disorder: RNA sequencing of whole blood in discordant twin and case-controlled cohorts

BackgroundA variety of DNA-based methods have been applied to identify genetic markers of attention deficit hyperactivity disorder (ADHD), but the connection to RNA-based gene expression has not been fully exploited.MethodsUsing well defined cohorts of discordant, monozygotic twins from the Michigan State University Twin Registry, and case-controlled ADHD cases in adolescents, the present studies utilized advanced single molecule RNA sequencing to identify expressed changes in whole blood RNA in ADHD. Multiple analytical strategies were employed to narrow differentially expressed RNA targets to a small set of potential biomarkers of ADHD.ResultsRNA markers common to both the discordant twin study and case-controlled subjects further narrowed the putative targets, some of which had been previously associated with ADHD at the DNA level. The potential role of several differentially expressed genes, including ABCB5, RGS2, GAK, GIT1 and 3 members of the galactose metabolism pathway (GALE, GALT, GALK1) are substantiated by prior associations to ADHD and by established mechanistic connections to molecular pathways relevant to ADHD and behavioral control.ConclusionsThe convergence of DNA, RNA, and metabolic data suggests these may be promising targets for diagnostics and therapeutics in ADHD.

Increased rates of eating disorders and their symptoms in women with major depressive disorder and anxiety disorders.

Individuals with eating disorders (EDs) have increased rates of major depressive disorder (MDD) and anxiety disorders. Yet, few studies have investigated rates of EDs and their symptoms in individuals presenting with MDD/anxiety disorders. Identifying potential disordered eating in people with MDD/anxiety disorders is important because even subclinical disordered eating is associated with reduced quality of life, and undiagnosed eating pathology may hinder treatment progress for both MDD/anxiety disorders and comorbid EDs. We compared rates of EDs (anorexia nervosa, bulimia nervosa, binge-eating disorder, and other specified feeding and eating disorders) and their symptoms in 130 women with, and 405 women without, lifetime MDD or an anxiety disorder (generalized anxiety disorder, obsessive-compulsive disorder, social phobia, specific phobia, panic disorder, agoraphobia, or post-traumatic stress disorder) recruited from the population-based Michigan State University Twin Registry. Lifetime ED and MDD/anxiety diagnoses, and lifetime clinically significant disordered eating behaviors (e.g., binge eating, excessive exercise) were assessed using the Structured Clinical Interview for DSM-IV (SCID). Among participants with lifetime MDD or any anxiety disorder, 13% met criteria for a lifetime ED and 39% reported engaging in at least one lifetime clinically significant disordered eating behavior (e.g., binge eating) on the SCID. In contrast, only 3% of participants without a history of MDD/an anxiety disorder met criteria for a lifetime ED, and only 11% reported lifetime clinically significant disordered eating behavior. Our findings suggest that women with MDD and anxiety disorders have elevated rates of EDs, and it is therefore imperative to screen for disordered eating in these populations.

Neighborhood poverty predicts altered neural and behavioral response inhibition

Socioeconomic disadvantage during childhood is associated with a myriad of negative adult outcomes. One mechanism through which disadvantage undermines positive outcomes may be by disrupting the development of self-control. The goal of the present study was to examine pathways from three key indicators of socioeconomic disadvantage – low family income, low maternal education, and neighborhood poverty – to neural and behavioral measures of response inhibition. We utilized data from a representative cohort of 215 twins (ages 7–18 years, 70% male) oversampled for exposure to disadvantage, who participated in the Michigan Twins Neurogenetics Study (MTwiNS), a study within the Michigan State University Twin Registry (MSUTR). Our child-friendly Go/No-Go task activated the bilateral inferior frontal gyrus (IFG), and activation during this task predicted behavioral inhibition performance, extending prior work on adults to youth. Critically, we also found that neighborhood poverty, assessed via geocoding, but not family income or maternal education, was associated with IFG activation, a finding that we replicated in an independent sample of disadvantaged youth. Further, we found that neighborhood poverty predicted response inhibition performance via its effect on IFG activation. These results provide the first mechanistic evidence that disadvantaged contexts may undermine self-control via their effect on the brain. The broader neighborhood, beyond familial contexts, may be critically important for this association, suggesting that contexts beyond the home have profound effects on the developing brain and behaviors critical for future health, wealth, and wellbeing.

Low emotion differentiation: An affective correlate of binge eating?

Low emotion differentiation (the tendency to experience vague affective states rather than discrete emotions) is associated with psychopathology marked by emotion regulation deficits and impulsive/maladaptive behavior. However, research examining associations between emotion differentiation and dysregulated eating is nascent and has yet to incorporate measures of clinically significant binge eating. Different measures of emotion differentiation have also been used, impeding cross-study comparisons. We therefore examined associations between several emotion differentiation measures and binge eating-related phenotypes across a spectrum of severity. Women (N = 482) from the Michigan State University Twin Registry completed the Positive and Negative Affect Schedule (PANAS) daily for 45 consecutive days. Three measures of negative/positive emotion differentiation (NED/PED) were created using the intraclass correlation coefficient (ICC), average interitem correlation, and average daily variance between negative/positive emotion ratings on the PANAS. Associations between NED/PED measures and emotional eating (EE) and a history of binge eating episodes (BEs) were then examined, controlling for affect intensity and BMI. Lower PED was associated with greater odds of BEs across the ICC and average interitem correlation measures, and more EE on the daily variance measure. Findings involving NED were less consistent; lower NED was associated with greater EE and greater odds of BEs using the daily variance measure only. Low PED is associated with clinically significant binge eating, and some aspects of NED may also be relevant for binge eating-related phenotypes. Further research examining the constructs captured by different emotion differentiation measures and their relevance to binge eating is needed.

Differences in genetic and environmental influences on body weight and shape concerns across pubertal development in females

The heritability of disordered eating increases during puberty; however, prior studies have largely examined a composite score of disordered eating, rather than specific symptoms. Body weight and shape concerns cut across all eating disorder diagnoses and are some of the strongest prospective risk factors for the development of eating disorders. Yet, little is known about potential developmental increases or decreases in genetic and environmental influences for these key symptoms. This study examined differences in genetic and environmental effects on a range of body weight and shape concerns during puberty and compared results to findings for overall levels of disordered eating symptoms. Participants were 926 same-sex female twins (ages 8–16) from the Michigan State University Twin Registry. Well-validated questionnaires were used to examine pubertal maturation, overall levels of disordered eating, and a range of cognitive body weight/shape constructs: body dissatisfaction, weight/shape concerns, and weight preoccupation. Findings for overall levels of disordered eating were very similar to those obtained in previous work, with significantly increased genetic effects in girls at more advanced pubertal development. Importantly, these same pubertal increases in genetic influences were observed for body dissatisfaction and weight/shape concerns. However, no pubertal moderation of genetic effects was observed for weight preoccupation; instead, pubertal moderation of nonshared and shared environmental effects was observed. Our findings point to differences in the extent to which genetic and environmental factors contribute to various cognitive body weight and shape symptoms during puberty.

Child Antisocial Behavior Is more Environmental in Origin in Disadvantaged Neighborhoods: Evidence Across Residents' Perceptions and Geographic Scales in Two Samples.

Prior research has suggested that disadvantaged neighborhood contexts alter the etiology of youth antisocial behavior (ASB). Unfortunately, these studies have relied exclusively on governmental data collected in administratively-defined neighborhoods (e.g., Census tracts or block groups, zip codes), a less than optimal approach for studying neighborhood effects. It would thus be important to extend prior findings of GxE using neighborhood sampling techniques, in which disadvantage is assessed via resident informant-reports of the neighborhood. The current study sought to do just this, examining two independent twin samples from the Michigan State University Twin Registry. Neighborhood disadvantage was assessed via maternal and neighbor informant-reports, the latter of which were analyzed multiple ways (i.e., all neighbors within 1km, nearest neighbor, and all neighbors within the County). Analyses revealed clear and consistent evidence of moderation by neighborhood disadvantage, regardless of informant or the specific operationalization of neighborhood. Shared environmental influences on ASB were observed to be several-fold larger in disadvantaged contexts, while genetic influences were proportionally more influential in advantaged neighborhoods. Such findings indicate that neighborhood disadvantage exerts rather profound effects on the origins of youth ASB. Efforts should now be made to identify the active ingredients of neighborhood disadvantage.

Elucidating factors underlying parent-offspring similarity in eating pathology in pre- and early puberty: Exploring the possibility of passive gene-environment correlation.

Familial resemblance in eating pathology is typically attributed to parents providing an environment that leads to the development of eating pathology. However, offspring raised by biological parents receive both their environment and genes from their parents, raising the possibility that genetic influences, environmental influences, and/or gene-environment interplay may account for familial resemblance. Past studies have not explored the possibility of parents' genes influencing the environment they provide (i.e., passive gene-environment correlations or "passive rGE"). If present, passive rGE is most likely to "hide" in estimates of shared environmental influence in classical twin models. The current study used a nuclear twin family design to explore the possibility of passive rGE during pre- and early puberty when past studies have demonstrated the importance of shared environmental influence. Additionally, the present study explored whether sibling-specific (i.e., influences specific to the twin generation) or family-specific (i.e., "cultural" influences within the home) environmental influences account for shared environmental influences found in past studies. Participants included preearly pubertal same-sex female twins and their biological parents (N = 547 families) from the Minnesota Twin Family Study and the Michigan State University Twin Registry. Disordered eating was assessed with self-report measures in the twins and parents. Pubertal status was determined using an established cut-off on a self-report measure. Passive rGE was not indicated in this study of pre- and early pubertal twins. Instead, sibling-specific shared environmental and nonshared environmental influences were most influential. Future research should work to identify the sibling-specific environmental influences that contribute to sibling similarity in disordered eating. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Michigan State University Twin Registry (MSUTR): 15 Years of Twin and Family Research.

The primary aim of the Michigan State University Twin Registry (MSUTR) is to examine developmental differences in genetic, environmental, neural, epigenetic, and neurobiological influences on psychopathology and resilience, particularly during childhood and adolescence. The MSUTR has two broad components: a large-scale, population-based registry of child, adolescent, and adult twins and their families (current N ~30,000) and a series of more focused and in-depth studies drawn from the registry (projected N ~7200). Participants in the population-based registry complete a family health and demographic questionnaire via mail. Families can then be recruited for one or more of the intensive, in-person studies from the population-based registry, using any one of several recruitment strategies (e.g., population-based, based on their answers to the registry questionnaire). These latter studies target a variety of biological, genetic, and environmental phenotypes, including multi-informant measures of psychiatric and behavioral phenotypes, functional and structural neuroimaging, comprehensive measures of the twin family environment (e.g., census and neighborhood informant reports of twin neighborhood characteristics, videotaped interactions of child twin families), buccal swab and salivary DNA samples, and/or assays of adolescent and adult steroid hormone levels. This article provides an overview of the MSUTR and describes current and future research directions.

Convergence in maternal and child reports of impulsivity, depressive symptoms, and trait anxiety, and their predictive utility for binge-eating behaviors.

Early detection of binge-eating (BE) behaviors and their risk factors is associated with better outcomes. A multi-informant approach for assessing BE psychopathology and risk factors has been emphasized to increase the probability and accuracy of early detection. Impulsivity (particularly negative and positive urgency), trait anxiety, and depressive symptoms are associated with BE behaviors. The present study examined maternal-child convergence of reports of child BE, impulsivity, trait anxiety, and depressive symptoms and examined the predictive power of maternal reports for child-reported BE behaviors. Participants included 927 female twins (aged 8-16 years) and 468 mothers from the Michigan State University Twin Registry. Risk factors and BE were assessed with self-report questionnaires. Intraclass correlation coefficients showed fair-to-moderate inter-rater agreement (ICCs = .31-.41) between maternal and child reports of risk factors and low-to-fair agreement for BE (ICCs = .05-.29). Controlling for the effects of age, pubertal status, body mass index, and family relatedness, multilevel models showed that maternal reports of child impulsivity, anxiety, and depressive symptoms did not add predictive power above and beyond child reports. Results call into question the utility and practical implications of using maternal reports to supplement child reports for BE and its risk factors.

Do neighborhood social processes moderate the etiology of youth conduct problems?

Prior work has robustly suggested that social processes in the neighborhood (i.e. informal social control, social cohesion, norms) influence child conduct problems (CP) and related outcomes, but has yet to consider how these community-level influences interact with individual-level genetic risk for CP. The current study sought to do just this, evaluating neighborhood-level social processes as etiologic moderators of child CP for the first time. We made use of two nested samples of child and adolescent twins within the Michigan State University Twin Registry (MSUTR): 5649 families who participated in in the Michigan Twins Project (MTP) and 1013 families who participated in the Twin Study of Behavioral and Emotional Development (TBED-C). The neighborhood social processes of informal social control, social cohesion, and norms were assessed using neighborhood sampling techniques, in which residents of each twin family's neighborhood reported on the social processes in their neighborhood. Standard biometric GxE analyses evaluated the extent to which they moderated the etiology of CP. The 'no moderation' model provided the best fit to the data in nearly all cases, arguing against neighborhood social processes as etiologic moderators of youth CP. The neighborhood social processes evaluated here do not appear to exert their effects on child CP via etiologic moderation. The documented links between neighborhood social processes and child CP are thus likely to reflect a different etiologic process. Possibilities include environmental main effects of neighborhood social processes on child CP, or genotype-environment correlations.

Associations between ovarian hormones and emotional eating across the menstrual cycle: Do ovulatory shifts in hormones matter?

Elevated ovarian hormone levels are associated with increased risk for binge eating (BE) and emotional eating (EE) during the midluteal phase of the menstrual cycle. However, past studies have not examined whether pronounced hormonal changes that precede the midluteal phase (i.e., the dramatic decrease in estradiol and increase in progesterone during/after ovulation) also influence midluteal increases in binge-related symptoms. Past theories and studies of phenotypes strongly related to BE (e.g., depression) suggest that these pronounced hormonal changes may also contribute. This study examined this possibility in 375 female twins (aged 15-25 years) from the Michigan State University Twin Registry. Daily ratings of EE (assessed with the Dutch Eating Behavior Questionnaire) and daily saliva samples of estradiol and progesterone were collected for 45 consecutive days. No significant associations were found between pronounced changes in estradiol or progesterone across ovulation and changes in EE scores in the midluteal phase. Results remained unchanged after controlling for body mass index and negative affect and examining participants with clinical BE episodes or more extreme hormonal fluctuations. In aggregate, the current findings and past data suggest that hormone levels are more significant predictors of EE than pronounced hormonal changes across the menstrual cycle.

No sex differences in the origins of covariation between social and physical aggression.

Prior work has indicated both theoretical and empirical overlap between social and physical aggression. The extent to which their covariance can be explained by the same underlying genetic or environmental factors, however, remains unclear. It is also uncertain whether or how the origins of their covariance might vary across sex. The current study sought to fill these gaps in the literature. We examined maternal and teacher reports of youth physical and social aggression in over 1000 6-10 years old (mean age = 8.02 years) twin pairs from the Michigan State University Twin Registry. We made use of the bivariate correlated factors model to clarify the origins of their association. We further tested both sex difference and no-sex difference versions of that model to determine whether there are sex differences in the association between social and physical aggression, as often assumed. The covariation between social and physical aggression was due to overlapping genetic factors and common environmental conditions. Specifically, 50-57% of the genetic factors, 74-100% of the shared environmental factors, and 28-40% of the unique environmental factors influencing physical aggression also influenced social aggression according to both mother and teacher reports. These shared etiological factors did not differ across sex. These findings argue against the common assumption that social aggression is the 'female version' of male physical aggression, and instead suggest that social aggression may be best conceptualized as a form of antisocial behavior that shares developmental pathways with other manifestations of externalizing pathology.

Abstract 090: Does Dietary Sodium Contribute to the Discordance in Blood Pressures among Monozygotic Twins?

Background: Dietary sodium (Na) and central adiposity are considered important risk factors for hypertension (HTN). Blood pressure (BP) levels are discordant among 40-50% of monozygotic (MZ) twin pairs. One prior study of MZ twins using questionnaires reported that hypertensive (HT) MZ twins differed in their intake of meat and milk. However, none of the previous studies have evaluated the impact of Na intake on BP in MZ twins. Methods: Eighty-eight pairs of MZ twins were enrolled from Milwaukee, WI and Michigan State University Twin Registry, East Lansing, MI (age- 44 ± 9 years, 63% women, and 96% Caucasian). BPs (measured in triplicate and averaged) and anthropometrics were measured. Na intake was calculated using Block Sodium Screener. Twin pairs were considered concordant or discordant based on systolic (SBP) or diastolic BP (DBP) difference of 10 mm Hg between co-twins, off BP medications Results: Thirty-seven twin pairs were discordant in their BP levels. Mean (± SD, mm Hg) SBP/DBPs among concordant and discordant twins were 120 ± 12 / 77 ± 9 and 131 ± 18 / 81 ± 10 respectively. Mean differences in SBP/DBP among concordant and discordant twins were 5 ± 7 / 4 ± 4 and 14 ± 8 / 10 ± 6 respectively. Discordant twins as a group had higher waist circumference (WC) compared to concordant twins (p<0.05), but with no differences in BMI or Na intake. However, among the discordant twin pairs, the co-twin with higher BPs (138 ± 18 / 85 ± 9) had higher dietary salt intakes (3900 ± 1437 vs. 3261 ± 1058 mg/d) and higher WC (105 ± 15 vs. 98 ± 18 cm) (p=0.02) compared to their co-twin with lower BPs (121 ± 16 / 77 ± 9). The average Na intake among the concordant twins was 3443 ± 1189 mg/day. Differences in Na intake among discordant co-twins remained statistically significant after adjustment for age, gender, BMI, WC, and waist-to-hip ratio. Conclusions: Higher Na intake is associated with higher BPs among MZ twins with discordant BPs. Differences in Na intakes were significant independent of central adiposity indicating significant Na sensitivity in discordant MZ twin pairs. The effect of ~500mg less Na intake/day in resulting in lower BPs in genetically identical individuals, suggests that modest decreases in Na-intake in Na-sensitive individuals may be sufficient to see the desired effect on BP levels.

It really does take a village: The role of neighbors in the etiology of nonaggressive rule-breaking behavior.

Although there is growing recognition that disadvantaged contexts attenuate genetic influences on youth misbehavior, it is not yet clear how this dampening occurs. The current study made use of a "geographic contagion" model to isolate specific contexts contributing to this effect, with a focus on nonaggressive rule-breaking behaviors (RB) in the families' neighbors. Our sample included 847 families residing in or near modestly-to-severely disadvantaged neighborhoods who participated in the Michigan State University Twin Registry. Neighborhood sampling techniques were used to recruit neighbors residing within 5km of a given family (the mean number of neighbors assessed per family was 13.09; range, 1-47). Analyses revealed clear evidence of genotype-environment interactions by neighbor RB, such that sibling-level shared environmental influences on child RB increased with increasing neighbor self-reports of their own RB, whereas genetic influences decreased. Moreover, this moderation appeared to be driven by geographic proximity to neighbors. Sensitivity analyses further indicated that this effect was specifically accounted for by higher levels of neighbor joblessness, rather than elements of neighbor RB that would contribute to neighborhood blight or crime. Such findings provocatively suggest that future genotype-environment interactions studies should integrate the dynamic networks of social contagion theory.

Estrogen moderates genetic influences on binge eating during puberty: Disruption of normative processes?

Puberty is a critical period for changes in genetic effects for binge eating in girls. Previous twin studies show increases in genetic influences on binge eating from prepuberty (∼0%) to midpuberty and beyond (∼50%). However, little is known about the factors that drive these shifts in genetic effects. A small pilot study showed that pubertal activation of estrogen may contribute to increases in genetic influences, possibly via hormonally induced changes in gene expression. However, large-scale studies investigating hormone effects on genetic risk are lacking. Thus, the purpose of the present study was to examine the effects of estrogen on genetic influences for binge eating in 964 female twins (ages 8-16 years) from the Michigan State University Twin Registry. Binge eating was assessed with the Minnesota Eating Behaviors Survey, whereas afternoon saliva samples were assayed for estradiol levels using standard enzyme immunoassays. Twin moderation models showed substantial differences in genetic influences on binge eating across estradiol levels. Stronger genetic effects were observed at lower (rather than higher) estradiol levels, even when controlling for the effects of age, body mass index, the physical changes of puberty, and the onset of menses. Overall, findings suggest that comparatively lower levels of estradiol during this critical period may disrupt normative developmental processes and enhance genetic influences on binge eating. (PsycINFO Database Record

Are there sex differences in the etiology of youth antisocial behavior?

Sex differences in the etiology of youth antisocial behavior are an intuitively appealing hypothesis given the consistently higher prevalence of antisocial behavior in boys versus girls. Although a few early studies supported this possibility, reporting stronger genetic influences in females and stronger environmental influences in males, subsequent meta-analyses found that antisocial behavior was equally heritable in males and females. Critically however, none of the meta-analyses evaluated whether sex differences in etiology might be enhanced in particular subpopulations or contexts. The current study sought to do just this. We examined 1,030 child twin pairs from the Michigan State University Twin Registry, half of whom were oversampled for neighborhood disadvantage, thereby allowing us to meaningfully evaluate whether sex differences in etiology were enhanced in disadvantaged contexts. We also directly evaluated the possibility of sex differences in the etiology of teacher- versus maternal-informant reports of antisocial behavior, evaluating each informant-report for possible sex differences. Results were not consistent with differential effects of sex on etiology in disadvantaged versus advantaged contexts, but did suggest moderation by informant-report. Namely, genetic influences were stronger in girls, and environmental influences were stronger in boys, when antisocial behavior was assessed using teacher informant-reports, but not when assessed using maternal informant-reports. Critically, these findings were confirmed when we reanalyzed meta-analytic data from Burt (2009a) separately by informant. Such findings suggest that, at least in school contexts, the etiology of antisocial behavior does indeed vary across sex. Implications are discussed. (PsycINFO Database Record

Abstract P528: Modifiable Factors Affecting BP in Identical Twins

Background: Genetic factors determining blood pressure (BP) are largely unmodifiable. Understanding the effects of physiologic, environmental, and epigenetic (modifiable) factors on BP levels can improve strategies for hypertension (HTN) control. Monozygotic (MZ) twins with identical genetic background are a good model to study the effect of these factors on BP. Methods: Seventy pairs of MZ twins were from Milwaukee, WI and Michigan State University Twin Registry, East Lansing, MI (62% women; age of 44 ± 10 years). BPs (measured in triplicate and averaged), anthropometrics, physical activity (Rapid Assessment of Physical Activity), and sodium intake measurements (Block Sodium Screener) were obtained. DNA was obtained from T-lymphocytes for methylation (epigenetic) sequencing analysis. Differences in systolic (SBP) and diastolic (DBP) BPs between co-twins were used as continuous variables for these analyses. Results: Mean SBP was 124 ± 15 mm Hg (mean ± SD) and DBP was 78 ± 11 mm Hg. Average differences in SBP and DBP among co-twins were 8 ± 9 and 7 ± 6 mm Hg respectively. Twin pairs were considered concordant or discordant based on BP difference of 10 mm Hg between co-twins or one twin being hypertensive. Discordant twins as a group had higher BMI and waist circumference (WC) compared to concordant twins (p<0.05). Among discordant twins, the co-twin with higher BPs tended to have higher waist circumference (WC) (105 ± 15 vs. 98 ± 18 cm) and dietary salt intake (3900 ± 1437 vs. 3261 ± 1058 mg/d) even though they did not reach statistical significance. There were no differences in physical activity or education levels. Genome-wide methylation analyses revealed that 3 loci were associated with SBP difference and 2 were associated with DBP difference at an unadjusted significance level of p < 10 -4 . Two sites reached an adjusted significance level of 0.08 with SBP difference. Conclusions: In this study, we identified several differentially methylated sites of interest in relation to BP among MZ twins. In addition, higher central adiposity and sodium intake may contribute to BP levels among MZ twins. Understanding the relationship of modifiable risk factors such as WC and sodium intake with methylation changes may shed light into novel pathogenic pathways for HTN.