Examining associations between genetic and neural risk for externalizing behaviors in adolescence and early adulthood

BACKGROUND

Researchers have identified genetic and neural risk factors for externalizing behaviors. However, it has not yet been determined if genetic liability is conferred in part through associations with more proximal neurophysiological risk markers.

METHODS

Participants from the Collaborative Study on the Genetics of Alcoholism, a large, family-based study of alcohol use disorders were genotyped and polygenic scores for externalizing (EXT PGS) were calculated. Associations with target P3 amplitude from a visual oddball task (P3) and broad endorsement of externalizing behaviors (indexed via self-report of alcohol and cannabis use, and antisocial behavior) were assessed in participants of European (EA; N = 2851) and African ancestry (AA; N = 1402). Analyses were also stratified by age (adolescents, age 12-17 and young adults, age 18-32).

RESULTS

The EXT PGS was significantly associated with higher levels of externalizing behaviors among EA adolescents and young adults as well as AA young adults. P3 was inversely associated with externalizing behaviors among EA young adults. EXT PGS was not significantly associated with P3 amplitude and therefore, there was no evidence that P3 amplitude indirectly accounted for the association between EXT PGS and externalizing behaviors.

CONCLUSIONS

Both the EXT PGS and P3 amplitude were significantly associated with externalizing behaviors among EA young adults. However, these associations with externalizing behaviors appear to be independent of each other, suggesting that they may index different facets of externalizing.

COVID-19 pandemic stressors are associated with reported increases in frequency of drunkenness among individuals with a history of alcohol use disorder

Some sources report increases in alcohol use have been observed since the start of the COVID-19 pandemic, particularly among women. Cross-sectional studies suggest that specific COVID-19-related stressful experiences (e.g., social disconnection) may be driving such increases in the general population. Few studies have explored these topics among individuals with a history of Alcohol Use Disorders (AUD), an especially vulnerable population. Drawing on recent data collected by the Collaborative Study on the Genetics of Alcoholism (COGA; COVID-19 study N = 1651, 62% women, age range: 30-91) in conjunction with AUD history data collected on the sample since 1990, we investigated associations of COVID-19 related stressors and coping activities with changes in drunkenness frequency since the start of the pandemic. Analyses were conducted for those without a history of AUD (N: 645) and three groups of participants with a history of AUD prior to the start of the pandemic: (1) those experiencing AUD symptoms (N: 606), (2) those in remission who were drinking (N: 231), and (3) those in remission who were abstinent (had not consumed alcohol for 5+ years; N: 169). Gender-stratified models were also examined. Exploratory analyses examined the moderating effects of 'problematic alcohol use' polygenic risk scores (PRS) and neural connectivity (i.e., posterior interhemispheric alpha EEG coherence) on associations between COVID-19 stressors and coping activities with changes in the frequency of drunkenness. Increases in drunkenness frequency since the start of the pandemic were higher among those with a lifetime AUD diagnosis experiencing symptoms prior to the start of the pandemic (14% reported increased drunkenness) when compared to those without a history of AUD (5% reported increased drunkenness). Among individuals in remission from AUD prior to the start of the pandemic, rates of increased drunkenness were 10% for those who were drinking pre-pandemic and 4% for those who had previously been abstinent. Across all groups, women reported nominally greater increases in drunkenness frequency when compared with men, although only women experiencing pre-pandemic AUD symptoms reported significantly greater rates of increased drunkenness since the start of the pandemic compared to men in this group (17% of women vs. 5% of men). Among those without a prior history of AUD, associations between COVID-19 risk and protective factors with increases in drunkenness frequency were not observed. Among all groups with a history of AUD (including those with AUD symptoms and those remitted from AUD), perceived stress was associated with increases in drunkenness. Among the remitted-abstinent group, essential worker status was associated with increases in drunkenness. Gender differences in these associations were observed: among women in the remitted-abstinent group, essential worker status, perceived stress, media consumption, and decreased social interactions were associated with increases in drunkenness. Among men in the remitted-drinking group, perceived stress was associated with increases in drunkenness, and increased relationship quality was associated with decreases in drunkenness. Exploratory analyses indicated that associations between family illness or death with increases in drunkenness and increased relationship quality with decreases in drunkenness were more pronounced among the remitted-drinking participants with higher PRS. Associations between family illness or death, media consumption, and economic hardships with increases in drunkenness and healthy coping with decreases in drunkenness were more pronounced among the remitted-abstinent group with lower interhemispheric alpha EEG connectivity. Our results demonstrated that only individuals with pre-pandemic AUD symptoms reported greater increases in drunkenness frequency since the start of the COVID-19 pandemic compared to those without a lifetime history of AUD. This increase was more pronounced among women than men in this group. However, COVID-19-related stressors and coping activities were associated with changes in the frequency of drunkenness among all groups of participants with a prior history of AUD, including those experiencing AUD symptoms, as well as abstinent and non-abstinent participants in remission. Perceived stress, essential worker status, media consumption, social connections (especially for women), and relationship quality (especially for men) are specific areas of focus for designing intervention and prevention strategies aimed at reducing pandemic-related alcohol misuse among this particularly vulnerable group. Interestingly, these associations were not observed for individuals without a prior history of AUD, supporting prior literature that demonstrates that widespread stressors (e.g., pandemics, terrorist attacks) disproportionately impact the mental health and alcohol use of those with a prior history of problems.

The collaborative study on the genetics of alcoholism: Genetics

This review describes the genetic approaches and results from the family-based Collaborative Study on the Genetics of Alcoholism (COGA). COGA was designed during the linkage era to identify genes affecting the risk for alcohol use disorder (AUD) and related problems, and was among the first AUD-focused studies to subsequently adopt a genome-wide association (GWAS) approach. COGA's family-based structure, multimodal assessment with gold-standard clinical and neurophysiological data, and the availability of prospective longitudinal phenotyping continues to provide insights into the etiology of AUD and related disorders. These include investigations of genetic risk and trajectories of substance use and use disorders, phenome-wide association studies of loci of interest, and investigations of pleiotropy, social genomics, genetic nurture, and within-family comparisons. COGA is one of the few AUD genetics projects that includes a substantial number of participants of African ancestry. The sharing of data and biospecimens has been a cornerstone of the COGA project, and COGA is a key contributor to large-scale GWAS consortia. COGA's wealth of publicly available genetic and extensive phenotyping data continues to provide a unique and adaptable resource for our understanding of the genetic etiology of AUD and related traits.

Genomic risk for post-traumatic stress disorder in families densely affected with alcohol use disorders

Recent genome-wide association studies (GWAS) have identified genetic markers of post-traumatic stress disorder (PTSD) in civilian and military populations. However, studies have yet to examine the genetics of PTSD while factoring in risk for alcohol dependence, which commonly co-occur. We examined genome-wide associations for DSM-IV PTSD among 4,978 trauma-exposed participants (31% with alcohol dependence, 50% female, 30% African ancestry) from the Collaborative Study on the Genetics of Alcoholism (COGA). We also examined associations of polygenic risk scores (PRS) derived from the Psychiatric Genomics Consortium (PGC)-PTSD Freeze 2 (N = 3533) and Million Veterans Program GWAS of PTSD (N = 5200) with PTSD and substance dependence in COGA, and moderating effects of sex and alcohol dependence. 7.3% of COGA participants met criteria for PTSD, with higher rates in females (10.1%) and those with alcohol dependence (12.3%). No independent loci met genome-wide significance in the PTSD meta-analysis of European (EA) and African ancestry (AA) participants. The PGC-PTSD PRS was associated with increased risk for PTSD (B = 0.126, p < 0.001), alcohol dependence (B = 0.231, p < 0.001), and cocaine dependence (B = 0.086, p < 0.01) in EA individuals. A significant interaction was observed, such that EA individuals with alcohol dependence and higher polygenic risk for PTSD were more likely to have PTSD (B = 0.090, p < 0.01) than those without alcohol dependence. These results further support the importance of examining substance dependence, specifically alcohol dependence, and PTSD together when investigating genetic influence on these disorders.

Association of parental divorce, discord, and polygenic risk with children's alcohol initiation and lifetime risk for alcohol use disorder

BACKGROUND

Parental divorce and discord are associated with poorer alcohol-related outcomes for offspring. However, not all children exposed to these stressors develop alcohol problems. Our objective was to test gene-by-environment interaction effects whereby children's genetic risk for alcohol problems modifies the effects of parental divorce and discord to predict alcohol outcomes.

METHODS

The sample included European (EA; N = 5608, 47% male, Mage  ~ 36 years) and African (AA; N = 1714, 46% female, Mage  ~ 33 years) ancestry participants from the Collaborative Study on the Genetics of Alcoholism. Outcomes included age at initiation of regular drinking and lifetime DSM-5 alcohol use disorder (AUD). Predictors included parental divorce, parental relationship discord, and offspring alcohol problems polygenic risk scores (PRSALC ). Mixed effects Cox proportional hazard models were used to examine alcohol initiation and generalized linear mixed effects models were used to examine lifetime AUD. Tests of PRS moderation of the effects of parental divorce/relationship discord on alcohol outcomes were examined on multiplicative and additive scales.

RESULTS

Among EA participants, parental divorce, parental discord, and higher PRSALC were associated with earlier alcohol initiation and greater lifetime AUD risk. Among AA participants, parental divorce was associated with earlier alcohol initiation and discord was associated with earlier initiation and AUD. PRSALC was not associated with either. Parental divorce/discord and PRSALC interacted on an additive scale in the EA sample, but no interactions were found in AA participants.

CONCLUSIONS

Children's genetic risk for alcohol problems modifies the impact of parental divorce/discord, consistent with an additive model of diathesis-stress interaction, with some differences across ancestry.

Genetic nurture effects for alcohol use disorder

We tested whether aspects of the childhood/adolescent home environment mediate genetic risk for alcohol problems within families across generations. Parental relationship discord and parental divorce were the focal environments examined. The sample included participants of European ancestry (N = 4806, 51% female) and African ancestry (N = 1960, 52% female) from the high-risk Collaborative Study on the Genetics of Alcoholism. Alcohol outcomes in the child generation included lifetime criterion counts for DSM-5 Alcohol Use Disorder (AUD), lifetime maximum drinks in 24 h, age at initiation of regular drinking, and age at first alcohol intoxication. Predictors in the parent generation included relationship discord, divorce, alcohol measures parallel to those in the child generation, and polygenic scores for alcohol problems. Parental polygenic scores were partitioned into alleles that were transmitted and non-transmitted to the child. The results from structural equation models were consistent with genetic nurture effects in European ancestry families. Exposure to parental relationship discord and parental divorce mediated, in part, the transmission of genetic risk for alcohol problems from parents to children to predict earlier ages regular drinking (βindirect = -0.018 [-0.026, -0.011]) and intoxication (βindirect = -0.015 [-0.023, -0.008]), greater lifetime maximum drinks (βindirect = 0.006 [0.002, 0.01]) and more lifetime AUD criteria (βindirect = 0.011 [0.006, 0.016]). In contrast, there was no evidence that parental alleles had indirect effects on offspring alcohol outcomes via parental relationship discord or divorce in the smaller number of families of African ancestry. In conclusion, parents transmit genetic risk for alcohol problems to their children not only directly, but also indirectly via genetically influenced aspects of the home environment. Further investigation of genetic nurture in non-European samples is needed.

Clinical, environmental, and genetic risk factors for substance use disorders: characterizing combined effects across multiple cohorts

Substance use disorders (SUDs) incur serious social and personal costs. The risk for SUDs is complex, with risk factors ranging from social conditions to individual genetic variation. We examined whether models that include a clinical/environmental risk index (CERI) and polygenic scores (PGS) are able to identify individuals at increased risk of SUD in young adulthood across four longitudinal cohorts for a combined sample of N = 15,134. Our analyses included participants of European (NEUR = 12,659) and African (NAFR = 2475) ancestries. SUD outcomes included: (1) alcohol dependence, (2) nicotine dependence; (3) drug dependence, and (4) any substance dependence. In the models containing the PGS and CERI, the CERI was associated with all three outcomes (ORs = 01.37-1.67). PGS for problematic alcohol use, externalizing, and smoking quantity were associated with alcohol dependence, drug dependence, and nicotine dependence, respectively (OR = 1.11-1.33). PGS for problematic alcohol use and externalizing were also associated with any substance dependence (ORs = 1.09-1.18). The full model explained 6-13% of the variance in SUDs. Those in the top 10% of CERI and PGS had relative risk ratios of 3.86-8.04 for each SUD relative to the bottom 90%. Overall, the combined measures of clinical, environmental, and genetic risk demonstrated modest ability to distinguish between affected and unaffected individuals in young adulthood. PGS were significant but added little in addition to the clinical/environmental risk index. Results from our analysis demonstrate there is still considerable work to be done before tools such as these are ready for clinical applications.

The role of parental genotype in the intergenerational transmission of externalizing behavior: Evidence for genetic nurturance

The purpose of this study was to examine possible pathways by which genetic risk associated with externalizing is transmitted in families. We used molecular data to disentangle the genetic and environmental pathways contributing to adolescent externalizing behavior in a sample of 1,111 adolescents (50% female; 719 European and 392 African ancestry) and their parents from the Collaborative Study on the Genetics of Alcoholism. We found evidence for genetic nurture such that parental externalizing polygenic scores were associated with adolescent externalizing behavior, over and above the effect of adolescents' own externalizing polygenic scores. Mediation analysis indicated that parental externalizing psychopathology partly explained the effect of parental genotype on children's externalizing behavior. We also found evidence for evocative gene-environment correlation, whereby adolescent externalizing polygenic scores were associated with lower parent-child communication, less parent-child closeness, and lower parental knowledge, controlling for parental genotype. These effects were observed among participants of European ancestry but not African ancestry, likely due to the limited predictive power of polygenic scores across ancestral background. These results demonstrate that in addition to genetic transmission, genes influence offspring behavior through the influence of parental genotypes on their children's environmental experiences, and the role of children's genotypes in shaping parent-child relationships.

Alcohol use disorder, psychiatric comorbidities, marriage and divorce in a high-risk sample

OBJECTIVE

To examine associations between alcohol use disorder (AUD), its psychiatric comorbidities, and their interactions, with marital outcomes in a diverse high-risk, genetically informative sample.

METHOD

Participants included European ancestry (EA; n = 4,045) and African ancestry (AA; n = 1,550) individuals from the multigenerational Collaborative Study on the Genetics of Alcoholism (COGA) sample (56% female, Mage ∼ 41 years). Outcomes were lifetime marriage and divorce. Predictors included lifetime AUD, an alcohol problems polygenic score (PRS), and AUD comorbidities, including conduct or antisocial personality disorder (ASP), cannabis dependence/abuse (CAN), frequent tobacco use (TOB), and major depressive disorder (MDD). Mixed effect Cox models and generalized linear mixed effects models were fit.

RESULTS

Among EA participants, those with AUD and CAN were less likely to marry (hazard ratios [HRs] 0.70-0.83, ps < 0.01). Among AA participants, those with AUD and TOB were less likely to marry (HRs 0.66-0.82, ps < 0.05) and those with MDD were more likely to marry (HR = 1.34, ps < 0.01). Among EA participants, AUD, CAN, TOB, and MDD were associated with higher odds of divorce (odds ratios [ORs] 1.59-2.21, ps < 0.01). Among AA participants, no predictors were significantly associated with divorce. Significant random effects indicated genetic and environmental influences on marriage, but only environmental factors on divorce.

CONCLUSIONS

In a high-risk sample, AUD was associated with reduced likelihood of marriage in EA and AA individuals and increased risk of divorce in EA individuals. These associations were largely independent of comorbidities. Genetic and environmental background factors contributed to marriage, while only environmental background factors contributed to divorce. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Item-Level Genome-Wide Association Study of the Alcohol Use Disorders Identification Test in Three Population-Based Cohorts

OBJECTIVE

Genome-wide association studies (GWASs) of the Alcohol Use Disorders Identification Test (AUDIT), a 10-item screen for alcohol use disorder (AUD), have elucidated novel loci for alcohol consumption and misuse. However, these studies also revealed that GWASs can be influenced by numerous biases (e.g., measurement error, selection bias), which may have led to inconsistent genetic correlations between alcohol involvement and AUD, as well as paradoxically negative genetic correlations between alcohol involvement and psychiatric disorders and/or medical conditions. The authors used genomic structural equation modeling to elucidate the genetics of alcohol consumption and problematic consequences of alcohol use as measured by AUDIT.

METHODS

To explore these unexpected differences in genetic correlations, the authors conducted the first item-level and the largest GWAS of AUDIT items (N=160,824) and applied a multivariate framework to mitigate previous biases.

RESULTS

The authors identified novel patterns of similarity (and dissimilarity) among the AUDIT items and found evidence of a correlated two-factor structure at the genetic level ("consumption" and "problems," rg=0.80). Moreover, by applying empirically derived weights to each of the AUDIT items, the authors constructed an aggregate measure of alcohol consumption that was strongly associated with alcohol dependence (rg=0.67), moderately associated with several other psychiatric disorders, and no longer positively associated with health and positive socioeconomic outcomes. Lastly, by conducting polygenic analyses in three independent cohorts that differed in their ascertainment and prevalence of AUD, the authors identified novel genetic associations between alcohol consumption, alcohol misuse, and health.

CONCLUSIONS

This work further emphasizes the value of AUDIT for both clinical and genetic studies of AUD and the importance of using multivariate methods to study genetic associations that are more closely related to AUD.

Impact of binge drinking during college on resting state functional connectivity

AIM

The current study examined the longitudinal effects of standard binge drinking (4+/5+ drinks for females/males in 2 hours) and extreme binge drinking (8+/10+ drinks for females/males in 2 hours) on resting-state functional connectivity.

METHOD

119 college students (61 males) were recruited in groups of distinct bingeing patterns at baseline: non-bingeing controls, standard and extreme bingers. Resting-state scans were first obtained when participants were freshmen/sophomores and again approximately two years later. Associations between longitudinal bingeing (reported during this two-year gap) and network connectivity were examined. Network connectivity was calculated by aggregating all edges affiliated with the same network (an edge is a functional connection between two brain regions). The relationship between longitudinal bingeing and connectivity edges was also studied using connectome-based predictive modeling (CPM).

RESULTS

Greater standard bingeing was negatively associated with change in connectivity between Default Mode Network and Ventral Attention Network (DMN-VAN; False Discovery Rate corrected), controlling for initial binge groups, longitudinal network changes, motions, scanner, SES, sex, and age. The correlations between change in DMN-VAN connectivity and change in cognitive performance (Stroop, Digit Span, Letter Fluency, and Trail Making) were also tested, but the results were not significant. Lastly, CPM failed to identify a generalizable predictive model of longitudinal bingeing from change in connectivity edges.

CONCLUSIONS

Binge drinking is associated with abnormality in networks implicated in attention and self-focused processes, which, in turn, have been implicated in rumination, craving, and relapse. More extensive alterations in functional connectivity might be observed with heavier or longer binge drinking pattern.

Mapping Pathways by Which Genetic Risk Influences Adolescent Externalizing Behavior: The Interplay Between Externalizing Polygenic Risk Scores, Parental Knowledge, and Peer Substance Use

Genetic predispositions and environmental influences both play an important role in adolescent externalizing behavior; however, they are not always independent. To elucidate gene-environment interplay, we examined the interrelationships between externalizing polygenic risk scores, parental knowledge, and peer substance use in impacting adolescent externalizing behavior across two time-points in a high-risk longitudinal sample of 1,200 adolescents (764 European and 436 African ancestry; Mage = 12.99) from the Collaborative Study on the Genetics of Alcoholism. Results from multivariate path analysis indicated that externalizing polygenic scores were directly associated with adolescent externalizing behavior but also indirectly via peer substance use, in the European ancestry sample. No significant polygenic association nor indirect effects of genetic risk were observed in the African ancestry group, likely due to more limited power. Our findings underscore the importance of gene-environment interplay and suggest peer substance use may be a mechanism through which genetic risk influences adolescent externalizing behavior.

Associations between Suicidal Thoughts and Behaviors and Genetic Liability for Cognitive Performance, Depression, and Risk-Taking in a High-Risk Sample

Background

Suicidal thoughts and behaviors (STBs) and nonsuicidal self-injury (NSSI) behaviors are moderately heritable and may reflect an underlying predisposition to depression, impulsivity, and cognitive vulnerabilities to varying degrees.

Objectives

We aimed to estimate the degrees of association between genetic liability to depression, impulsivity, and cognitive performance and STBs and NSSI in a high-risk sample.

Methods

We used data on 7,482 individuals of European ancestry and 3,359 individuals of African ancestry from the Collaborative Study on the Genetics of Alcoholism to examine the links between polygenic scores (PGSs) for depression, impulsivity/risk-taking, and cognitive performance with 3 self-reported indices of STBs (suicidal ideation, persistent suicidal ideation defined as ideation occurring on at least 7 consecutive days, and suicide attempt) and with NSSI.

Results

The PGS for depression was significantly associated with all 4 primary self-harm measures, explaining 0.6-2.5% of the variance. The PGS for risk-taking behaviors was also associated with all 4 self-harm behaviors in baseline models, but was no longer associated after controlling for a lifetime measure of DSM-IV alcohol dependence and abuse symptom counts. Polygenic predisposition for cognitive performance was negatively associated with suicide attempts (q = 3.8e-4) but was not significantly associated with suicidal ideation nor NSSI. We did not find any significant associations in the African ancestry subset, likely due to smaller sample sizes.

Conclusions

Our results encourage the study of STB as transdiagnostic outcomes that show genetic overlap with a range of risk factors.

Alcohol-Related, Drug-Related, and Non-Substance-Related Aggression: 3 Facets of a Single Construct or 3 Distinct Constructs?

BACKGROUND

Aggression often occurs alongside alcohol and drug misuse. However, it is not clear whether the latent and manifest relations among alcohol-related, drug-related, and non-substance-related aggression are separate manifestations of a single construct or instead are 3 distinct constructs.

METHODS

To examine these associations, we conducted a preregistered analysis of 13,490 participants in the Collaborative Study on the Genetics of Alcoholism. In a structured interview, participants reported their lifetime perpetration of these 3 aggression phenotypes.

RESULTS

The data were better fit by a model that treated these aggression phenotypes as 3 distinct latent factors, as compared to models in which the items all loaded onto 1 ("general") or 2 ("substance-related" and "non-substance-related") aggression factors. This 3-factor model fit better for men than women. Subsequent exploratory analyses then showed that among these 3 factors, alcohol-related aggression explained the variance of overall aggression better than the other 2 factors.

CONCLUSIONS

Our findings suggest that these 3 forms of aggression are distinct phenotypes (especially among men). Yet, people's alcohol-related aggression can accurately characterize their overall aggressive tendencies across these domains. Future research will benefit from articulating the unique and shared pathways and risk factors underlying each of these facets of aggression.

Behavioral inhibition and reward processing in college binge drinkers with and without marijuana use

AIM

Binge drinking is common during college, and studies have shown that many college students drink in quantities that far exceed the standard binge drinking threshold. Previous research has noted personality differences in individuals who engage in binge drinking, but few studies have examined neurobiological differences in both standard bingers (4/5 drinks in two hours for females/males; sBinge) and extreme binge drinkers (8+/10+ drinks in two hours for females/males; eBinge).

METHOD

The current study of 221 college students used functional magnetic resonance imaging (fMRI) to study neural activation on a stop signal task (SST) to assess behavioral inhibition and a monetary incentive delay (MID) task to assess activation to rewards and losses. Non-bingeing controls, sBinge, and eBinge freshmen and sophomores were recruited. In addition, because binge/extreme binge drinking is often associated with marijuana (MJ) use, MJ + sBinge and MJ + eBinge groups were also included.

RESULTS

All five groups showed strong activation in expected key cortical and striatal regions on both the SST and the MID. However, there were no significant differences between groups either at the whole-brain level or in specific regions of interest. Behavioral performance on the fMRI tasks also did not differ between groups.

CONCLUSIONS

These results suggest that our sample of individuals who engage in binge or extreme binge drinking with or without MJ co-use do not differ in brain activity on reward and inhibitory tasks. Neural differences may be present on other cognitive tasks or may emerge later after more sustained use of alcohol, MJ, and other drugs.

RISK FACTORS FOR HEARING IMPAIRMENT IN TYPE 1 DIABETES

Objective: Studies have demonstrated that glycated hemoglobin (HbA1c) is a significant predictor of hearing impairment in type 1 diabetes. We identified additional factors associated with hearing impairment in participants with type 1 diabetes from the Diabetes Control and Complications Trial and its observational follow-up, the Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study. Methods: A total of 1,150 DCCT/EDIC participants were recruited for the Hearing Study. A medical history, physical measurements, and a self-administered hearing questionnaire were obtained. Audiometry was performed by study-certified personnel and assessed centrally. Logistic regression models assessed the association of risk factors and comorbidities with speech- and high-frequency hearing impairment. Results: Mean age was 55 ± 7 years, duration of diabetes 34 ± 5 years, and DCCT/EDIC HbA1c 7.9 ± 0.9% (63 mmol/mol). In multivariable models, higher odds of speech-frequency impairment were significantly associated with older age, higher HbA1c, history of noise exposure, male sex, and higher triglycerides. Higher odds of high-frequency impairment were associated with older age, male sex, history of noise exposure, higher skin intrinsic florescence (SIF) as a marker of tissue glycation, higher HbA1c, nonprofessional/nontechnical occupations, sedentary activity, and lower low-density-lipoprotein cholesterol. Among participants who previously completed computed tomography and carotid ultrasonography, coronary artery calcification (CAC) >0 and carotid intima-medial thickness were significantly associated with high-but not speech-frequency impairment. Conclusion: Consistent with previous reports, male sex, age, several metabolic factors, and noise exposure are independently associated with hearing impairment. The association with SIF further emphasizes the importance of glycemia-as a modifiable risk factor-over time. In addition, the macrovascular contribution of CAC is novel and important. Abbreviations: AER = albumin excretion rate; CAC = coronary artery calcification; CVD = cardiovascular disease; DCCT/EDIC = Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications; eGFR = estimated glomerular filtration rate; ETDRS = Early Treatment Diabetic Retinopathy Study; HbA1c = glycated hemoglobin; HDL = high-density lipoprotein; IMT = intima-media thickness; LDL = low-density lipoprotein; NHANES = National Health and Nutrition Examination Survey; OR = odds ratio; SIF = skin intrinsic fluorescence; T1D = type 1 diabetes.

A Pilot Follow-Up Study of Older Alcohol-Dependent COGA Adults

BACKGROUND

Alcohol consumption and problems are increasing among older adults, who are at elevated risk for alcohol-related accidents and medical problems. This paper describes a pilot follow-up of older adults with a history of alcohol dependence that was designed to determine the feasibility of conducting a more extensive investigation.

METHODS

The sample consisted of previously assessed subjects in the Collaborative Studies on the Genetics of Alcoholism who: (i) were age 50+; (ii) had lifetime DSM-IV AD; and (iii) had DNA available. Individuals were located through family contacts, Internet searches, and death registries. A brief telephone interview assessed demographics, health, and alcohol involvement.

RESULTS

Of the total sample (N = 2,174), 36% were contacted, 24% were deceased, and 40% were not yet located. Most (89%) contacted subjects were interviewed, and 99% of them agreed to future evaluation. Thirty percent of interviewed subjects reported abstinence for 10+ years, 56% reported drinking within the past year, and 14% last drank between >1 and 10 years ago. There were no age-related past-year differences in weekly consumption (overall sample mean: 16 drinks), number of drinking weeks (30.8), maximum number of drinks in 24 hours (8.1), or prevalence of weekly risky drinking (19%). Among those who drank within the past 5 years, the 3 most common alcohol-related problems were spending excessive time drinking or recovering (49%), drinking more/longer than intended (35%), and driving while intoxicated (35%); and about a third (32%) received some form of treatment.

CONCLUSIONS

Over a 1-year period, we located 60% of individuals last seen an average of 23 years ago. The majority of contacted individuals were interviewed and willing to be evaluated again. Although the proportion of individuals currently drinking diminished with age, subjects exhibited troublesome levels of alcohol consumption and problems. Our findings suggest the importance and feasibility of a more comprehensive follow-up.

Association Between Age and Familial Risk for Alcoholism on Functional Connectivity in Adolescence

OBJECTIVE

Youth with a family history of alcohol use disorder (family history positive [FHP]) are at increased risk for developing maladaptive substance use relative to family history negative (FHN) peers. Building on earlier studies demonstrating morphological differences and distinct patterns of neural activation in FHP, the purpose of the present study was to investigate differential intrinsic functional connectivity among brain networks indexing premorbid risk of developing alcohol use disorder (AUD).

METHOD

The current study examined intrinsic functional connectivity using resting state functional magnetic resonance imaging in 191 adolescents 13 to 18 years of age with and without family history of AUD via independent component analysis, a method enabling data-driven investigation of internetwork and intranetwork connectivity among brain regions at rest.

RESULTS

Analyses revealed significantly lower intranetwork connectivity in FHP compared to FHN participants between the dorsal premotor cortex and other sensorimotor network regions. Reduced intranetwork connectivity in this region was further correlated with the number of biological family members with AUD and mood disorders. Robust differences were also evident in internetwork connectivity as a function of age. However, there was no evidence for family history by age interactions.

CONCLUSION

Intra- but not internetwork connectivity appears to differentiate FHP and FHN adolescents, whereas age differences within adolescence are marked by differences in internetwork connectivity.

Validation of HIV-infected cohort identification using automated clinical data in the Department of Veterans Affairs

OBJECTIVES

The US Department of Veterans Affairs (VA) is the largest integrated health care provider for HIV-infected patients in the USA. VA data for HIV-specific clinical and quality improvement research are an important resource. We sought to determine the accuracy of using the VA Corporate Data Warehouse (CDW), a fully automated medical records database for all VA users nationally, to identify HIV-infected patients compared with a gold-standard VA HIV Clinical Case Registry (CCR).

METHODS

We assessed the test performance characteristics of each of our CDW criteria-based algorithms (presence of one, two or all of the following: diagnostic codes for HIV, positive HIV laboratory tests, and prescription for HIV medication) by calculating their sensitivity (proportion of HIV-positive patients in the CCR accurately detected as HIV-positive by the CDW algorithm) and positive predictive value (PPV; the proportion of patients identified by the CDW algorithm who were classified as HIV-positive from the CCR).

RESULTS

We found that using a CDW algorithm requiring two of three HIV diagnostic criteria yielded the highest sensitivity (95.2%) with very little trade-off in PPV (93.5%).

CONCLUSIONS

A two diagnostic criteria-based algorithm can be utilized to accurately identify HIV-infected cohorts seen in the nationwide VA health care system.

Personality traits and negative consequences associated with binge drinking and marijuana use in college students

Background: Binge drinking is common in college students, and many drink in quantities greater than the standard definition of bingeing. Combined use of additional substances, particularly marijuana, is also common. Objectives: Increased impulsivity and sensation seeking are risk factors for bingeing, and this study was designed to characterize their association with extreme compared to standard bingeing, as well as with combined bingeing and marijuana use. Negative consequences of alcohol use were also investigated. Methods: Self-report personality measures and a measure of the negative consequences of alcohol use were given to a sample of 221 college students (109 females) sorted into a control and 4 binge groups based upon their patterns of bingeing and marijuana use. Narrowly defined, non-overlapping measures of impulsivity and sensation seeking were analyzed to assess the association of these personality measures with substance-use patterns and negative consequences of bingeing. Results: Standard bingers did not differ from non-bingeing controls on either impulsivity or sensation seeking, whereas extreme bingers had significantly higher impulsivity and sensation seeking scores than controls and also significantly higher sensation seeking than standard bingers. Exploratory analyses of a broader set of personality scales showed that a disinhibition scale was also significant predictor of substance use group. A number of personality traits significantly predicted substance use patterns as well as specific negative consequences of bingeing. Conclusions: Impulsivity, sensation seeking and disinhibition are significant associates of substance use patterns and the negative consequences of use in college students.

Exploring the relationship between polygenic risk for cannabis use, peer cannabis use and the longitudinal course of cannabis involvement

BACKGROUND AND AIMS

Few studies have explored how polygenic propensity to cannabis use unfolds across development, and no studies have yet examined this question in the context of environmental contributions such as peer cannabis use. Outlining the factors that contribute to progression from cannabis initiation to problem use over time may ultimately provide insights into mechanisms for targeted interventions. We sought to examine the relationships between polygenic liability for cannabis use, cannabis use trajectories from ages 12-30 years and perceived peer cannabis use at ages 12-17 years.

DESIGN

Mixed-effect logistic and linear regressions were used to examine associations between polygenic risk scores, cannabis use trajectory membership and perceived peer cannabis use.

SETTING

United States.

PARTICIPANTS

From the Collaborative Study on the Genetics of Alcoholism (COGA) study, a cohort of 1167 individuals aged 12-26 years at their baseline (i.e. first) interview.

MEASUREMENTS

Key measurements included life-time cannabis use (yes/no), frequency of past 12-month cannabis use, maximum life-time frequency of cannabis use, cannabis use disorder (using DSM-5 criteria) and perceived peer cannabis use. Polygenic risk scores (PRS) were created using summary statistics from a large (n = 162 082) genome-wide association study (GWAS) of cannabis use.

FINDINGS

Three trajectories reflecting no/low (n = 844), moderate (n = 137) and high (n = 186) use were identified. PRS were significantly associated with trajectory membership [P = 0.002-0.006, maximum conditional R2  = 1.4%, odds ratios (ORs) = 1.40-1.49]. Individuals who reported that most/all of their best friends used cannabis had significantly higher PRS than those who reported that none of their friends were users [OR = 1.35, 95% confidence interval (CI) = 1.04, 1.75, P = 0.023]. Perceived peer use itself explained up to 11.3% of the variance in trajectory class membership (OR = 1.50-4.65). When peer cannabis use and the cannabis use PRS were entered into the model simultaneously, both the PRS and peer use continued to be significantly associated with class membership (P < 0.01).

CONCLUSIONS

Genetic propensity to cannabis use derived from heterogeneous samples appears to correlate with longitudinal increases in cannabis use frequency in young adults.

Positive and negative reinforcement are differentially associated with alcohol consumption as a function of alcohol dependence

A multistage model of drug addiction in which individuals' motivations for use change as they develop problems is widely accepted; however, the evidence for this model comes mostly from animal work and cross-sectional studies. We used longitudinal data to test whether positive and negative reinforcement associated with alcohol consumption differed as a function of alcohol dependence (AD). Specifically, we tested whether (a) positive reinforcement is more strongly associated with alcohol consumption than is negative reinforcement among individuals without AD, (b) negative reinforcement is more strongly associated with AD than is positive reinforcement, and (c) in the presence of AD, the association between positive reinforcement and alcohol consumption becomes weaker, whereas the association with negative reinforcement becomes stronger. We included assessments between Ages 18 and 30 years from participants who indicated they ever had a drink (N = 2,556; 51.6% female) from the Collaborative Study on the Genetics of Alcoholism Prospective Study. Results from generalized estimating equations indicated that positive, but not negative, reinforcement was associated with alcohol consumption among individuals without AD. Both positive and negative reinforcement were associated with AD, but the association was stronger with negative reinforcement. Results from the multilevel growth model indicated that the association between negative reinforcement and alcohol consumption became stronger with the presence of AD, whereas the association between positive reinforcement and alcohol consumption did not differ as a function of AD. We provide empirical evidence that positive and negative reinforcement are differentially associated with alcohol consumption as a function of AD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Hearing Impairment and Type 1 Diabetes in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Cohort

OBJECTIVE

To evaluate the prevalence of hearing impairment in participants with type 1 diabetes enrolled in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study and compare with that of a spousal control group without diabetes. Among participants with type 1 diabetes, to evaluate the association of hearing impairment with prior DCCT therapy and overall glycemia.

RESEARCH DESIGN AND METHODS

DCCT/EDIC participants (n = 1,150) and 288 spouses without diabetes were recruited for the DCCT/EDIC Hearing Study. All subjects completed a self-administered questionnaire, medical history, and physical measurements. Audiometry was performed by study-certified personnel; audiograms were assessed centrally. Speech-frequency (pure-tone average [PTA] thresholds at 500, 1,000, 2,000, and 4,000 Hz) and high-frequency impairment (PTA thresholds at 3,000, 4,000, 6,000, and 8,000 Hz) were defined as PTA >25 dB hearing loss. Logistic regression models were adjusted for age and sex.

RESULTS

DCCT/EDIC participants and spousal control subjects were similar in age, race, education, smoking, and systolic blood pressure. There were no statistically significant differences between groups in the prevalence or adjusted odds of speech- or high-frequency impairment in either ear. Among participants with type 1 diabetes, for every 10% increase in the time-weighted mean HbA_1c, there was a 32% (95% CI 1.15-1.50) and 19% (95% CI 1.07-1.33) increase in speech- and high-frequency hearing impairment, respectively.

CONCLUSIONS

We found no significant difference in the prevalence of hearing impairment between the group with type 1 diabetes and the spousal control group. Among those with type 1 diabetes, higher mean HbA_1c over time was associated with hearing impairment.

Influence of Parental Alcohol Dependence Symptoms and Parenting on Adolescent Risky Drinking and Conduct Problems: A Family Systems Perspective

BACKGROUND

Parental alcohol problems are associated with adverse adolescent outcomes such as risky drinking and conduct problems. Important questions remain about the unique roles of fathers' and mothers' alcohol problems and differences and/or similarities in pathways of risk across ethnicity and gender. In this study, we used a family systems approach to consider spillover and crossover effects of fathers' and mothers' alcohol problems (number of alcohol dependence symptoms [ADS]) and parenting behaviors in relation to adolescents' risky drinking and conduct problems.

METHODS

The sample included 1,282 adolescents (aged 12 to 17) and their parents from the Collaborative Study on the Genetics of Alcoholism. Parents completed the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA), and adolescents completed an adolescent version of SSAGA. Data were analyzed using multivariate structural equation modeling.

RESULTS

Fathers' ADS count was associated with higher adolescent risky drinking and conduct problems indirectly via disruption to fathers' and mothers' positive parenting behaviors, whereas mothers' ADS count was not associated with adolescents' risky drinking and conduct problems directly or indirectly via positive parenting behaviors. No differences in these associations were found across ethnic background and offspring gender.

CONCLUSIONS

Findings highlight the importance of considering the unique roles of fathers' and mothers' ADS in influencing family processes and adolescent outcomes.

Associations of parental alcohol use disorders and parental separation with offspring initiation of alcohol, cigarette and cannabis use and sexual debut in high-risk families

BACKGROUND AND AIMS

Parental alcohol use disorders (AUDs) and parental separation are associated with increased risk for early use of alcohol in offspring, but whether they increase risks for early use of other substances and for early sexual debut is under-studied. We focused on associations of parental AUDs and parental separation with substance initiation and sexual debut to (1) test the strength of the associations of parental AUDs and parental separation with time to initiation (age in years) of alcohol, tobacco and cannabis use and sexual debut and (2) compare the strength of association of parental AUD and parental separation with initiation.

DESIGN

Prospective adolescent and young adult cohort of a high-risk family study, the Collaborative Study on the Genetics of Alcoholism (COGA).

SETTING

Six sites in the United States.

PARTICIPANTS

A total of 3257 offspring (aged 14-33 years) first assessed in 2004 and sought for interview approximately every 2 years thereafter; 1945 (59.7%) offspring had a parent with an AUD.

MEASUREMENTS

Diagnostic interview data on offspring substance use and sexual debut were based on first report of these experiences. Parental life-time AUD was based on their own self-report when parents were interviewed (1991-2005) for most parents, or on offspring and other family member reports for parents who were not interviewed. Parental separation was based on offspring reports of not living with both biological parents most of the time between ages 12 and 17 years.

FINDINGS

Parental AUDs were associated with increased hazards for all outcomes, with cumulative hazards ranging from 1.19 to 2.71. Parental separation was also an independent and consistent predictor of early substance use and sexual debut, with hazards ranging from 1.19 to 2.34. The strength of association of parental separation with substance initiation was equal to that of having two AUD-affected parents, and its association with sexual debut was stronger than the association of parental AUD in one or both parents.

CONCLUSIONS

Parental alcohol use disorders (AUDs) and parental separation are independent and consistent predictors of increased risk for early alcohol, tobacco and cannabis use and sexual debut in offspring from families with a high risk of parental AUDs.

CYP2A6 metabolism in the development of smoking behaviors in young adults

Cytochrome P450 2A6 (CYP2A6) encodes the enzyme responsible for the majority of nicotine metabolism. Previous studies support that slow metabolizers smoke fewer cigarettes once nicotine dependent but provide conflicting results on the role of CYP2A6 in the development of dependence. By focusing on the critical period of young adulthood, this study examines the relationship of CYP2A6 variation and smoking milestones. A total of 1209 European American young adults enrolled in the Collaborative Study on the Genetics of Alcoholism were genotyped for CYP2A6 variants to calculate a previously well-validated metric that estimates nicotine metabolism. This metric was not associated with the transition from never smoking to smoking initiation nor with the transition from initiation to daily smoking (P > 0.4). But among young adults who had become daily smokers (n = 506), decreased metabolism was associated with increased risk of nicotine dependence (P = 0.03) (defined as Fagerström Test for Nicotine Dependence score ≥4). This finding was replicated in the Collaborative Genetic Study of Nicotine Dependence with 335 young adult daily smokers (P = 0.02). Secondary meta-analysis indicated that slow metabolizers had a 53 percent increased odds (OR = 1.53, 95 percent CI 1.11-2.11, P = 0.009) of developing nicotine dependence compared with normal metabolizers. Furthermore, secondary analyses examining four-level response of time to first cigarette after waking (>60, 31-60, 6-30, ≤5 minutes) demonstrated a robust effect of the metabolism metric in Collaborative Study on the Genetics of Alcoholism (P = 0.03) and Collaborative Genetic Study of Nicotine Dependence (P = 0.004), illustrating the important role of this measure of dependence. These findings highlight the complex role of CYP2A6 variation across different developmental stages of smoking behaviors.

Cortical Thickness in Adolescents with a Family History of Alcohol Use Disorder

BACKGROUND

Individuals with a family history (FH+) of alcohol use disorder (AUD) have a higher risk for developing an AUD than those with no family history (FH-) of AUD. In addition, FH+ individuals tend to perform worse on neuropsychological measures and show heightened impulsivity, which may be due to underlying differences in brain structure such as cortical thickness. The primary aim of this study was to investigate differences in cortical thickness in FH+ compared to FH- adolescents. Secondary aims were to (i) investigate differences in executive functioning and impulsivity, and (ii) examine associations between brain structure and behavior.

METHODS

Brain scans of 95 FH- and 93 FH+ subjects aged 13 to 18 were obtained using magnetic resonance imaging. FH+ subjects were required to have at least 1 biological parent with a history of an AUD. FH+ and FH- individuals had limited or no past alcohol use, thereby minimizing potential effects of alcohol. Subjects were evaluated on impulsivity and executive functioning tasks. Thicknesses of cortical lobes and subregions were analyzed using FreeSurfer. Regions showing group differences were examined for group-by-age interactions and correlations with neuropsychological and personality measures.

RESULTS

FH+ adolescents had thinner cortices in frontal and parietal lobes, notably in the medial orbitofrontal, lateral orbitofrontal, and superior parietal cortices. The difference in cortical thickness between family history groups was strongest among the youngest subjects. FH+ subjects were also more impulsive and had poorer performance on a spatial memory task.

CONCLUSIONS

These findings demonstrate frontal and parietal structural differences in FH+ adolescents that might underlie cognitive and behavioral characteristics associated with AUD risk.

Familial association of abstinent remission from alcohol use disorder in first-degree relatives of alcohol-dependent treatment-seeking probands

BACKGROUND AND AIMS

Studies that have included family history of alcohol use disorder (AUD) as a predictor of remission from AUD have yielded few significant results. The goals of this study were to estimate the association of persistent AUD, non-abstinent remission and abstinent remission ('AUD/remission status') in a proband with AUD/remission status in a relative and to test whether this association differed in related and unrelated proband-relative pairs.

DESIGN

High-risk family study of alcohol dependence. Probands were recruited from treatment settings and relatives were invited to participate. Baseline assessments occurred between 1991 and 1998 with follow-up between 1996 and 2005. Half of probands were matched with a biological 1st-degree relative with life-time AUD (related group) and half of probands were paired with an unrelated individual with life-time AUD (unrelated group).

SETTING

Brooklyn, New York; Indianapolis, Indiana; Iowa City, Iowa; San Diego, California; Farmington, Connecticut; and St Louis, Missouri, USA.

PARTICIPANTS

A total of 606 probands (25.7% female, mean age 37.7) with baseline and follow-up data and 606 of their 1st-degree relatives who had life-ime AUDs (45.8% female, mean age 36.2 years).

MEASUREMENTS

Persistent AUD, non-abstinent remission and abstinent remission were based on self-report interview data on most recent AUD symptoms and alcohol consumption. Dependent variable was relatives' AUD/remission status. Independent variable was probands' AUD/remission status.

FINDINGS

A total of 34.6% of probands and 20.6% of relatives were abstinent and 11.1% of probands and 22.8% of relatives were in non-abstinent remission. AUD/remission status was correlated significantly in related (r = 0.23, P = 0.0037) but not in unrelated pairs. A significant interaction of probands' abstinent remission with a variable representing related (versus unrelated, P = 0.003) pairs suggested a familial association for abstinent remission. In related pairs, individuals with an abstinent proband were more likely to be abstinent themselves than were individuals whose proband had persistent AUD [relative risk ratio = 3.27, 95% confidence interval (CI) = 1.56-6.85, P = 0.002]; this association was not significant in unrelated pairs.

CONCLUSIONS

The likelihood of abstinent remission among people with alcohol use disorder appears to be more than three times greater for individuals who are related to an abstinent proband versus those related to a proband with persistent alcohol use disorder.

Validity of code based algorithms to identify primary open angle glaucoma (POAG) in Veterans Affairs (VA) administrative databases

PURPOSE

The validity of the International Classification of Diseases, 9th revision, Clinical Modification (ICD-9) code for primary open angle glaucoma (POAG) in the Department of Veterans Affairs (VA) electronic medical record has not been examined. We determined the accuracy of the ICD-9 code for POAG and developed diagnostic algorithms for the detection of POAG.

METHODS

We conducted a retrospective study of abstracted data from the Michael E. DeBakey VA Medical Center's medical records of 334 unique patients with at least one visit to the Eye Clinic between 1999 and 2013. Algorithms were developed to validly identify POAG using ICD-9 codes and pharmacy data. The positive predictive value (PPV), negative predictive value (NPV), sensitivity, specificity and percent agreement of the various algorithms were calculated.

RESULTS

For the ICD-9 code 365.1x, the PPV was 65.9%, NPV was 95.2%, sensitivity was 100%, specificity was 82.6%, and percent agreement was 87.8%. The algorithm with the highest PPV was 76.3%, using pharmacy data in conjunction with two or more ICD-9 codes for POAG, but this algorithm also had the lowest NPV at 88.2%.

CONCLUSIONS

Various algorithms for identifying POAG in the VA administrative databases have variable validity. Depending on the type of research being done, the ICD-9 code 365.1x can be used for epidemiologic or health services database research.

Reciprocal relationships between substance use and disorders and suicidal ideation and suicide attempts in the Collaborative Study of the Genetics of Alcoholism

BACKGROUND

Substance use and misuse and suicidal thoughts and behaviors tend to co-occur. The purpose of this study was to examine whether (a) suicidal ideation and attempt are related to onset of alcohol, nicotine and cannabis use and dependence; (b) early use of alcohol, nicotine and cannabis is associated with onset of suicidal ideation and attempt; and (c) whether these associations persist while controlling for covariates, such as family history of alcohol problems, major depression and other internalizing and externalizing disorders.

METHODS

The prospective cohort of the Collaborative Study of the Genetics of Alcoholism (COGA; N=3277) was used. Cross-sectional and discrete time logistic regression (i.e. survival) analyses examined associations between suicidal ideation and attempt and onset of alcohol, nicotine and cannabis use and dependence. Survival models also examined whether individual early substance use was related to onset of ideation and attempt.

RESULTS

Ideation was related to 0.71-0.77 odds of onset of subsequent alcohol, nicotine and cannabis use. Attempt was associated with 1.44-1.61 odds of later alcohol, nicotine and cannabis dependence, even after accounting for covariates. Evidence for early substance use being related to subsequent onset of ideation or attempt was limited. Several sex and race differences emerged.

LIMITATIONS

The sample was ascertained for family history of alcoholism; not all participants had been followed up allowing for censored observations; reporting bias.

CONCLUSION

Suicide attempts are associated with increased likelihood of onset of substance dependence.

Comparison of Parent, Peer, Psychiatric, and Cannabis Use Influences Across Stages of Offspring Alcohol Involvement: Evidence from the COGA Prospective Study

BACKGROUND

All stages of development of alcohol use disorder (AUD) have not been equally studied. While initiation of drinking has been given considerable attention, other stages have not been as thoroughly investigated. It is not clear whether the same factors are associated consistently across early and late transitions in AUD involvement. High-risk family samples that are enriched for AUD vulnerability and transitions in AUD development offer an opportunity to examine influences across multiple stages of AUD development.

METHODS

Data from adolescents and young adults from high-risk families were used to study 4 transitions in AUD development-time to first drink, first drink to first problem, first drink to first diagnosis, and first problem to first diagnosis. Cox modeling was used to compare associations of parental AUD, parental separation, peer substance use, offspring ever-use of cannabis, trauma exposures, and internalizing and externalizing psychopathology across transitions.

RESULTS

Hazards of most transitions were elevated for those who had ever used cannabis, those who attributed substance use to their peers, those with externalizing disorders, and those with parents with AUD. Many risk factors were linked to early initiation of alcohol, particularly cannabis use. Internalizing disorders were associated with later stages. Nonassaultive trauma was associated only with early initiation; assaultive trauma was not associated with any transition.

CONCLUSIONS

In this large, ethnically diverse sample of high-risk youth, significant influences across transitions were fairly consistent, with externalizing disorders and cannabis ever-use elevating the likelihood of each stage, and peer and parental (and especially maternal AUD) influences linked to initiation and some later stages. Finally, in light of the increasingly permissive legal and social stances toward cannabis in the United States, the marked elevations of all alcohol outcomes observed for cannabis use underscore the importance of studying the underpinnings of this relationship.

Physical activity and the risk of Barrett's esophagus

Physical activity either directly or through influencing body fat may affect the risk of Barrett's esophagus (BE). However, the effect of physical activity on the risk of developing BE has not been examined. We conducted a case-control study among consecutive eligible patients either scheduled for elective endoscopy or recruited from primary care clinics to undergo a study endoscopy. Study participants completed the International Physical Activity Questionnaire (IPAQ) short form that measures physical activity during the past 7 days. We categorized level of physical activity by low, moderate, or high and estimated metabolic equivalent minutes per week (MET min/week). We calculated odds ratios (ORs) using logistic regression models and adjusted for age, sex, race, gastroesophageal reflux disease symptoms, Helicobacter pylori infection, body mass index, and waist-to-hip ratio. There were 307 cases with BE and 1724 controls (1262 from endoscopy and 462 from the primary care clinic) with IPAQ information. BE cases were more likely to be in the high-category physical activity category than controls (14.3% vs. 11.5% P = 0.08). However, there were no differences in the overall average MET min/week for walking between BE cases and controls (909 vs. 561; P = 0.16), with similar findings among those with moderate activity (1094 vs. 755, P = 0.18) or vigorous activity (784 vs. 826, P = 0.93). In multivariable logistic regression, physical activity level was not significantly associated with BE (OR = 1.19, 95% confidence interval: 0.82-1.73). Recent amount and intensity of physical activity are not associated with a reduction in the risk of BE. Studies are required to examine the long-term effects of physical activity.

Genetic influences on alcohol use across stages of development: GABRA2 and longitudinal trajectories of drunkenness from adolescence to young adulthood

Longitudinal analyses allow us to understand how genetic risk unfolds across development, in a way that is not possible with cross-sectional analyses of individuals at different ages. This has received little attention in genetic association analyses. In this study, we test for genetic effects of GABRA2, a gene previously associated with alcohol dependence, on trajectories of drunkenness from age 14 to 25. We use data from 1070 individuals who participated in the prospective sample of the Collaborative Study on the Genetics of Alcoholism, in order to better understand the unfolding of genetic risk across development. Piecewise linear growth models were fit to model the influence of genotype on rate of increase in drunkenness from early adolescence to young adulthood (14-18 years), the change in drunkenness during the transition to adulthood (18-19 years) and the rate of change in drunkenness across young adulthood (≥ 19 years). Variation in GABRA2 was associated with an increase in drunkenness that occurred at the transition between adolescence and adulthood. The genotypic effect was more pronounced in females. These analyses illustrate the importance of longitudinal data to characterize how genetic effects unfold across development. The findings suggest that transitions across important developmental periods may alter the relative importance of genetic effects on patterns of alcohol use. The findings also suggest the importance of considering gender when evaluating genetic effects on drinking patterns in males and females.

An ADH1B variant and peer drinking in progression to adolescent drinking milestones: evidence of a gene-by-environment interaction

BACKGROUND

Adolescent drinking is an important public health concern, one that is influenced by both genetic and environmental factors. The functional variant rs1229984 in alcohol dehydrogenase 1B (ADH1B) has been associated at a genome-wide level with alcohol use disorders in diverse adult populations. However, few data are available regarding whether this variant influences early drinking behaviors and whether social context moderates this effect. This study examines the interplay between rs1229984 and peer drinking in the development of adolescent drinking milestones.

METHODS

One thousand five hundred and fifty European and African American individuals who had a full drink of alcohol before age 18 were selected from a longitudinal study of youth as part of the Collaborative Study on the Genetics of Alcoholism (COGA). Cox proportional hazards regression, with G × E product terms in the final models, was used to study 2 primary outcomes during adolescence: age of first intoxication and age of first DSM-5 alcohol use disorder symptom.

RESULTS

The minor A allele of rs1229984 was associated with a protective effect for first intoxication (HR = 0.56, 95% CI 0.41 to 0.76) and first DSM-5 symptom (HR = 0.45, 95% CI 0.26 to 0.77) in the final models. Reporting that most or all best friends drink was associated with a hazardous effect for first intoxication (HR = 1.81, 95% CI 1.62 to 2.01) and first DSM-5 symptom (HR = 2.17, 95% 1.88 to 2.50) in the final models. Furthermore, there was a significant G × E interaction for first intoxication (p = 0.002) and first DSM-5 symptom (p = 0.01). Among individuals reporting none or few best friends drinking, the ADH1B variant had a protective effect for adolescent drinking milestones, but for those reporting most or all best friends drinking, this effect was greatly reduced.

CONCLUSIONS

Our results suggest that the risk factor of best friends drinking attenuates the protective effect of a well-established ADH1B variant for 2 adolescent drinking behaviors. These findings illustrate the interplay between genetic and environmental factors in the development of drinking milestones during adolescence.

Using genetic information from candidate gene and genome-wide association studies in risk prediction for alcohol dependence

Family-based and genome-wide association studies (GWAS) of alcohol dependence (AD) have reported numerous associated variants. The clinical validity of these variants for predicting AD compared with family history information has not been reported. Using the Collaborative Study on the Genetics of Alcoholism (COGA) and the Study of Addiction: Genes and Environment (SAGE) GWAS samples, we examined the aggregate impact of multiple single nucleotide polymorphisms (SNPs) on risk prediction. We created genetic sum scores by adding risk alleles associated in discovery samples, and then tested the scores for their ability to discriminate between cases and controls in validation samples. Genetic sum scores were assessed separately for SNPs associated with AD in candidate gene studies and SNPs from GWAS analyses that met varying P-value thresholds. Candidate gene sum scores did not exhibit significant predictive accuracy. Family history was a better classifier of case-control status, with a significant area under the receiver operating characteristic curve (AUC) of 0.686 in COGA and 0.614 in SAGE. SNPs that met less stringent P-value thresholds of 0.01-0.50 in GWAS analyses yielded significant AUC estimates, ranging from mean estimates of 0.549 for SNPs with P < 0.01 to 0.565 for SNPs with P < 0.50. This study suggests that SNPs currently have limited clinical utility, but there is potential for enhanced predictive ability with better understanding of the large number of variants that might contribute to risk.

Social contexts of remission from DSM-5 alcohol use disorder in a high-risk sample

BACKGROUND

Measures of social context, such as marriage and religious participation, are associated with remission from alcohol use disorders (AUDs) in population-based and treatment samples, but whether these associations hold among individuals at high familial risk for AUD is unknown. This study tests associations of measures of social context and treatment with different types of remission from DSM-5 AUD in a high-risk sample.

METHODS

Subjects were 686 relatives of probands (85.7% first-degree) who participated in a high-risk family study of alcohol dependence. All subjects met criteria for AUD at baseline and were re-interviewed 5 years later. Follow-up status was categorized as persistent AUD, high-risk drinking, remitted low-risk drinking, and abstinence. Social context measures were defined as stable or changing from baseline to follow-up, and their bivariate and multivariate associations with follow-up status were tested.

RESULTS

At follow-up, 62.8% of subjects had persistent AUD, 6.4% were high-risk drinkers, 22.2% were remitted low-risk drinkers, and 8.6% were abstinent. Birth of first child during the interval was the only measure of social context associated with remitted low-risk drinking and was significant for women only. Abstinent remission was characterized by being stably separated or divorced for women, new marriage for both sexes, experiencing low levels of family support and high levels of friend support, and receiving treatment. High-risk drinkers were more likely than individuals with persistent AUD to have a stable number of children and to have been recently unemployed.

CONCLUSIONS

The social contexts accompanying different types of remission in this high-risk sample resemble those found in population-based and clinical samples. Low-risk drinkers resemble natural remitters from population-based samples who change their drinking habits with life transitions. Abstainers resemble clinical samples in marital context, support from friends, and treatment. High-risk drinkers appear to continue to experience negative consequences of heavy drinking.

On the association of common and rare genetic variation influencing body mass index: a combined SNP and CNV analysis

Background

As the architecture of complex traits incorporates a widening spectrum of genetic variation, analyses integrating common and rare variation are needed. Body mass index (BMI) represents a model trait, since common variation shows robust association but accounts for a fraction of the heritability. A combined analysis of single nucleotide polymorphisms (SNP) and copy number variation (CNV) was performed using 1850 European and 498 African-Americans from the Study of Addiction: Genetics and Environment. Genetic risk sum scores (GRSS) were constructed using 32 BMI-validated SNPs and aggregate-risk methods were compared: count versus weighted and proxy versus imputation.

Results

The weighted SNP-GRSS constructed from imputed probabilities of risk alleles performed best and was highly associated with BMI (p = 4.3×10⁻¹⁶) accounting for 3% of the phenotypic variance. In addition to BMI-validated SNPs, common and rare BMI/obesity-associated CNVs were identified from the literature. Of the 84 CNVs previously reported, only 21-kilobase deletions on 16p12.3 showed evidence for association with BMI (p = 0.003, frequency = 16.9%), with two CNVs nominally associated with class II obesity, 1p36.1 duplications (OR = 3.1, p = 0.009, frequency 1.2%) and 5q13.2 deletions (OR = 1.5, p = 0.048, frequency 7.7%). All other CNVs, individually and in aggregate, were not associated with BMI or obesity. The combined model, including covariates, SNP-GRSS, and 16p12.3 deletion accounted for 11.5% of phenotypic variance in BMI (3.2% from genetic effects). Models significantly predicted obesity classification with maximum discriminative ability for morbid-obesity (p = 3.15×10⁻¹⁸).

Conclusion

Results show that incorporating validated effect sizes and allelic probabilities improve prediction algorithms. Although rare-CNVs did not account for significant phenotypic variation, results provide a framework for integrated analyses.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-368) contains supplementary material, which is available to authorized users.

DSM-5 cannabis use disorder: a phenotypic and genomic perspective

BACKGROUND

We explore the factor structure of DSM-5 cannabis use disorders, examine its prevalence across European- and African-American respondents as well as its genetic underpinnings, utilizing data from a genome-wide study of single nucleotide polymorphisms (SNPs). We also estimate the heritability of DSM-5 cannabis use disorders explained by these common SNPs.

METHODS

Data on 3053 subjects reporting a lifetime history of cannabis use were utilized. Exploratory and confirmatory factor analyses were conducted to create a factor score, which was used in a genome-wide association analysis. p-values from the single SNP analysis were examined for evidence of gene-based association. The aggregate effect of all SNPs was also estimated using Genome-Wide Complex Traits Analysis.

RESULTS

The unidimensionality of DSM-5 cannabis use disorder criteria was demonstrated. Comparing DSM-IV to DSM-5, a decrease in prevalence of cannabis use disorders was only noted in European-American respondents and was exceedingly modest. For the DSM-5 cannabis use disorders factor score, no SNP surpassed the genome-wide significance testing threshold. However, in the European-American subsample, gene-based association testing resulted in significant associations in 3 genes (C17orf58, BPTF and PPM1D) on chromosome 17q24. In aggregate, 21% of the variance in DSM-5 cannabis use disorders was explained by the genome-wide SNPs; however, this estimate was not statistically significant.

CONCLUSIONS

DSM-5 cannabis use disorder represents a unidimensional construct, the prevalence of which is only modestly elevated above the DSM-IV version. Considerably larger sample sizes will be required to identify individual SNPs associated with cannabis use disorders and unequivocally establish its polygenic underpinnings.

A model to determine the likely age of an adolescent's first drink of alcohol

OBJECTIVE

With the use of a new cohort of adolescent subjects, predictors from the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) interview and the Achenbach Youth Self Report (YSR) were combined to model age of first drink (AFD).

METHODS

Subjects consisted of 820 adolescents (ages 14-17) drawn from the current phase of the Collaborative Study on the Genetics of Alcoholism. Three Cox proportional hazards models were considered. Model 1 contained SSAGA variables equivalent to AFD predictors from our previous study: interview age, family history of alcohol dependence, and number of conduct disorder symptoms. Model 2 incorporated 2 additional SSAGA questions (best friends drink and smoked a cigarette before a reported AFD) plus 8 YSR-derived scale scores. Model 3 was a reduced version of model 2, retaining only significant predictors.

RESULTS

Model 2 was a significant improvement over model 1. Model 3 was the best and the most parsimonious of the 3 with respect to likelihood ratio and Wald χ(2) tests and retained only 5 variables from model 2. Included variables were the following: (1) best friends drink, (2) membership in a high-risk alcohol dependence family, (3) number of conduct disorder symptoms, (4) YSR externalizing score, and (5) YSR social problems score.

CONCLUSIONS

Adding variables to those from our original study improved our ability to model the likely age of alcohol initiation. In addition to the SSAGA, the YSR appears to have utility as a research tool to predict the age of alcohol initiation.

Intrinsic versus laser-induced fluorescence spectroscopy for coronary atherosclerosis: a generational comparison model for testing diagnostic accuracy

Laser-induced fluorescence (LIF) and intrinsic fluorescence spectroscopy (IFS) have been used experimentally for diagnosing coronary atherosclerosis. In this study, we demonstrated the diagnostic superiority of IFS at 342-nm excitation (IFS(342)) versus LIF (LIF(342)) and described a protocol for head-to-head comparison of old (LIF) versus new (IFS) generations of similar diagnostic methods, labeled as "generational comparison model". IFS(342) and LIF(342) were modeled with basis spectra of media, fibrous caps, and superficial foam cells and of their correspondent chemicals (elastin, collagen, and lipoproteins). The average accuracy and receiver operating characteristic area under the curve of IFS(342) in single-, double-, and triple-parameter diagnostic algorithm iterations, geared toward identifying 84 atherosclerotic specimens from a group of 117 coronary segments, was 90% ± 1% and 0.87 ± 0.025, superior to LIF(342) (84% ± 3% and 0.84 ± 0.016; P = 0.0002 and 0.02, respectively) in a generational comparison model.

Participant characteristics and study features associated with high retention rates in a longitudinal investigation of type 1 diabetes mellitus

BACKGROUND

The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study has sustained an extraordinarily high level of participant involvement for over two decades.

PURPOSE

In order to identify specific characteristics of EDIC that contributed most strongly to retention, study-designed questionnaires were distributed to 1334 participants.

METHODS

Confidential questionnaires were completed during EDIC Years 15-17. Participants were classified as Completely Adherent (completed all visits), Partly Adherent (missed >1 visit or major portion of a visit), or Inactive (did not participate for >5 years). Questionnaire items addressed specific aspects of clinic visits, evaluation procedures, staff-participant relationships, and medical/health-care support provided by EDIC.

RESULTS

The most commonly cited reasons for continuing participation were Cutting Edge Tests to assess diabetes complications (79.3%), Annual Evaluations (67.7%), a desire to Help Others (65.2%), and Better Care for Diabetes (61.6%). Women chose Cutting Edge Tests as their first or second most important reason significantly more often than men, whereas men chose Better Care for Diabetes more frequently. Individuals with at least three diabetes-related complications were more likely than those with fewer complications to choose Annual Evaluations as their first or second reason for continued involvement.

LIMITATIONS

The small proportion of individuals who discontinued participation restricted our ability to identify factors associated with suspended involvement. In addition, our analysis is limited to a cohort with type 1 diabetes followed in an observational study after an average participation time of 6.5 years in a randomized trial.

CONCLUSIONS

The primary reasons identified by respondents for their long-term commitment are consistent with shorter-term studies and underscore the importance of expert medical care, supportive staff-participant relationships, and involvement with clinically and scientifically meaningful research.

The aggregate effect of dopamine genes on dependence symptoms among cocaine users: cross-validation of a candidate system scoring approach

Genome-wide studies of psychiatric conditions frequently fail to explain a substantial proportion of variance, and replication of individual SNP effects is rare. We demonstrate a selective scoring approach, in which variants from several genes known to directly affect the dopamine system are considered concurrently to explain individual differences in cocaine dependence symptoms. 273 SNPs from eight dopamine-related genes were tested for association with cocaine dependence symptoms in an initial training sample. We identified a four-SNP score that accounted for 0.55% of the variance in a separate testing sample (p = 0.037). These findings suggest that (1) limiting investigated SNPs to those located in genes of theoretical importance improves the chances of identifying replicable effects by reducing statistical penalties for multiple testing, and (2) considering top-associated SNPs in the aggregate can reveal replicable effects that are too small to be identified at the level of individual SNPs.

Copy number variations in 6q14.1 and 5q13.2 are associated with alcohol dependence

BACKGROUND

Excessive alcohol use is the third leading cause of preventable death and is highly correlated with alcohol dependence, a heritable phenotype. Many genetic factors for alcohol dependence have been found, but many remain unknown. In search of additional genetic factors, we examined the association between Diagnostic and StatisticalManual of Mental Disorders, Fourth Edition (DSM-IV) alcohol dependence and all common copy number variations (CNVs) with good reliability in the Study of Addiction: Genetics and Environment (SAGE).

METHODS

All participants in SAGE were interviewed using the Semi-Structured Assessment for the Genetics of Alcoholism, as a part of 3 contributing studies. A total of 2,610 non-Hispanic European American samples were genotyped on the Illumina Human 1M array. We performed CNV calling by CNVPartition, PennCNV, and QuantiSNP, and only CNVs identified by all 3 software programs were examined. Association was conducted with the CNV (as a deletion/duplication) as well as with probes in the CNV region. Quantitative polymerase chain reaction (qPCR) was used to validate the CNVs in the laboratory.

RESULTS

CNVs in 6q14.1 (p = 1.04 × 10(-6)) and 5q13.2 (p = 3.37 × 10(-4)) were significantly associated with alcohol dependence after adjusting multiple tests. On chromosome 5q13.2, there were multiple candidate genes previously associated with various neurological disorders. The region on chromosome 6q14.1 is a gene desert that has been associated with mental retardation and language delay. The CNV in 5q13.2 was validated, whereas only a component of the CNV on 6q14.1 was validated by qPCR. Thus, the CNV on 6q14.1 should be viewed with caution.

CONCLUSIONS

This is the first study to show an association between DSM-IV alcohol dependence and CNVs. CNVs in regions previously associated with neurological disorders may be associated with alcohol dependence.

Functioning of alcohol use disorder criteria among men and women with arrests for driving under the influence of alcohol

BACKGROUND

Many states require screening of individuals arrested for driving under the influence (DUI) of alcohol to determine recidivism risk and the need for treatment based on severity of alcohol problems. Several screening instruments use DSM-IV criteria for alcohol abuse and dependence to assess alcohol problems in this population, but whether they adequately measure alcohol problems in individuals with DUIs has not been examined. In addition, gender differences in DUI samples suggest that female offenders have more severe alcohol problems than male offenders. The current study examines differences in alcohol criteria functioning by DUI history and gender using an item response theory (IRT) approach.

METHODS

Data from diagnostic interviews with 8,605 participants in the Collaborative Study on the Genetics of Alcoholism, including 1,655 who ever reported a DUI arrest (20% women), were used to examine differences in alcohol criteria functioning between men and women with and without DUIs. The factor underlying item response was conceptualized as unidimensional, representing alcohol problem severity.

RESULTS

Social/interpersonal problems, larger/longer, and inability/persistent desire to quit displayed greater discrimination of IRT-defined alcohol problem severity among individuals with DUIs than those without. Irrespective of DUI status, women had a higher threshold than men for time spent drinking or recovering. Women without DUIs had a higher threshold than similar men for social/interpersonal problems. Taken as a whole, the criteria yielded similar amounts of information in all groups.

CONCLUSIONS

DSM-IV criteria for alcohol abuse and dependence adequately detect alcohol problem severity in individuals with DUIs, and some are better at detecting severity in this particularly high-risk group than in individuals without DUIs. However, the criteria as a whole are equally effective in measuring alcohol problem severity among individuals with and without DUIs and may be used with confidence in screening DUI offenders.

Mechanism of ceroid formation in atherosclerotic plaque: in situ studies using a combination of Raman and fluorescence spectroscopy

Accumulation of the lipid-protein complex ceroid is a characteristic of atherosclerotic plaque. The mechanism of ceroid formation has been extensively studied, because the complex is postulated to contribute to plaque irreversibility. Despite intensive research, ceroid deposits are defined through their fluorescence and histochemical staining properties, while their composition remains unknown. Using Raman and fluorescence spectral microscopy, we examine the composition of ceroid in situ in aorta and coronary artery plaque. The synergy of these two types of spectroscopy allows for identification of ceroid via its fluorescence signature and elucidation of its chemical composition through the acquisition of a Raman spectrum. In accordance with in vitro predictions, low density lipoprotein (LDL) appears within the deposits primarily in its peroxidized form. The main forms of modified LDL detected in both coronary artery and aortic plaques are peroxidation products from the Fenton reaction and myeloperoxidase-hypochlorite pathway. These two peroxidation products occur in similar concentrations within the deposits and represent ∼40 and 30% of the total LDL (native and peroxidized) in the aorta and coronary artery deposits, respectively. To our knowledge, this study is the first to successfully employ Raman spectroscopy to unravel a metabolic pathway involved in disease pathogenesis: the formation of ceroid in atherosclerotic plaque.

Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque

Early detection and treatment of rupture-prone vulnerable atherosclerotic plaques is critical to reducing patient mortality associated with cardiovascular disease. The combination of reflectance, fluorescence, and Raman spectroscopy-termed multimodal spectroscopy (MMS)-provides detailed biochemical information about tissue and can detect vulnerable plaque features: thin fibrous cap (TFC), necrotic core (NC), superficial foam cells (SFC), and thrombus. Ex vivo MMS spectra are collected from 12 patients that underwent carotid endarterectomy or femoral bypass surgery. Data are collected by means of a unitary MMS optical fiber probe and a portable clinical instrument. Blinded histopathological analysis is used to assess the vulnerability of each spectrally evaluated artery lesion. Modeling of the ex vivo MMS spectra produce objective parameters that correlate with the presence of vulnerable plaque features: TFC with fluorescence parameters indicative of collagen presence; NC∕SFC with a combination of diffuse reflectance β-carotene∕ceroid absorption and the Raman spectral signature of lipids; and thrombus with its Raman signature. Using these parameters, suspected vulnerable plaques can be detected with a sensitivity of 96% and specificity of 72%. These encouraging results warrant the continued development of MMS as a catheter-based clinical diagnostic technique for early detection of vulnerable plaques.

Detection of coronary atherosclerotic plaques with superficial proteoglycans and foam cells using real-time intrinsic fluorescence spectroscopy

OBJECTIVES

The protein components of low-density lipoprotein (LDL), oxidized LDL and proteoglycans such as versican contain tryptophan, an amino acid with characteristic fluorescence features at 308 nm excitation wavelength. We hypothesize that intrinsic fluorescence spectroscopy at 308 nm excitation wavelength IFS308, a method suitable for clinical use, can identify coronary artery lesions with superficial foam cells (SFCs) and/or proteoglycans.

METHODS

We subjected 119 human coronary artery specimens to in vitro fluorescence and reflectance spectroscopy. We used 5 basis spectra to model IFS308, and extracted their contributions to each individual IFS308 spectrum. A diagnostic algorithm using the contributions of Total Tryptophan and fibrous cap to IFS308 was built to identify specimens with SFCs and/or proteoglycans in their top 50 μm.

RESULTS

We detected SFCs and/or proteoglycans, such as versican or the glycosaminoglycan hyaluronan, in 24 fibrous cap atheromas or pathologic intimal thickening (PIT) lesions. An algorithm using the contributions of Total Tryptophan and fibrous cap to IFS308 was able to identify these segments with 92% sensitivity and 80% specificity.

CONCLUSION

We were able to establish a set of characteristic LDL, oxidized LDL, versican and hyaluronan fluorescence spectra, ready to be used for real-time diagnosis. The IFS(308) technique detects SFCs and/or proteoglycans in fibrous cap atheromas and PIT lesions. SFCs and proteoglycans are histological markers of vulnerable plaques, and this study is a step further in developing an invasive clinical tool to detect the vulnerable atherosclerotic plaque.

Predicting sensation seeking from dopamine genes. A candidate-system approach

Sensation seeking is a heritable personality trait that has been reliably linked to behavioral disorders. The dopamine system has been hypothesized to contribute to variations in sensation seeking between different individuals, and both experimental and observational studies in humans and nonhuman animals provide evidence for the involvement of the dopamine system in sensation-seeking behavior. In this study, we took a candidate-system approach to genetic association analysis of sensation-seeking behavior. We analyzed single-nucleotide polymorphisms (SNPs) from a number of dopaminergic genes. Using 273 SNPs from eight dopamine genes in a sample of 635 unrelated individuals, we examined the aggregate effect of SNPs that were significantly associated with sensation-seeking behavior. Multiple SNPs in four dopamine genes accounted for significant variance in sensation-seeking behavior between individuals. These results suggest that multiple SNPs, aggregated within genes that are relevant to a specific neurobiological system, form a genetic-risk score that may explain a significant proportion of observed variance in human traits such as sensation-seeking behavior.

Predictors of sexual debut at age 16 or younger

The present study examined the extent to which variables within the self system (i.e., symptoms of alcohol dependence and conduct disorder, gender, race, and metropolitan status) and the familial system (i.e., having an alcohol dependent biological parent or second-degree relative, religious background, educational background of parents, and being born to a teenage mother) were associated with sexual debut at 16 years old or earlier. Participants were 1,054 biological relatives, aged 18-25 years, of alcohol dependent probands who participated in the Collaborative Study on the Genetics of Alcoholism project. Comparison participants (N = 234) without alcohol dependent biological parents were also evaluated. Clinical and sociodemographic variables were assessed by structured, personal interviews. Parental history of alcohol dependence was evaluated by direct interview of parents in most cases and family history in uninterviewed parents. In a multivariate survival analysis, increased risk of becoming sexually active at 16 years of age or earlier was significantly associated with 6 of the 10 predictor variables, including race, one or more alcohol dependence symptoms, and/or one or more conduct disorder symptoms. Having an alcohol dependent biological parent or second-degree relative (e.g., aunt, uncle, or grandparent), educational background of mother, and being born to a teenage mother were also significantly associated with increased risk. These results provide evidence that specific variables in the self and familial systems of influence are important in predicting sexual debut at 16 years old or earlier.