Review: Use of Asian samples in genetic research of alcohol use disorders: Genetic variation of alcohol metabolizing enzymes and the effects of acetaldehyde

Comparison of emergency transport for acute alcohol intoxication before and after the coronavirus disease 2019 pandemic: A retrospective observational study

The ongoing coronavirus disease 2019 (COVID-19) pandemic has had a broad effect on social, economic, educational, and political systems. We investigated the effect of COVID-19 on emergency transportation due to acute alcohol intoxication in the Kochi Prefecture in Japan, a region with high alcohol consumption. This retrospective observational study was conducted using the data of 62,138 patients from the Kochi-Iryo-Net database, Kochi Prefecture's emergency medical and wide-area disaster information system. Chi-square tests and multiple logistic regression analyses were performed to examine the association between emergency transportation and alcohol intoxication. This analysis compared the monthly number of transportations during 2019 (as reference) with that throughout 2020 and 2021. Approximately 1.5 % of all emergency transportation cases were related to acute alcohol intoxication. The number of emergency transportation cases due to acute alcohol intoxication declined by 0.5 % in 2020 and 0.7 % in 2021 compared with that in 2019. Moreover, compared with that in 2019, the number of cases of emergency transportation due to acute alcohol intoxication significantly decreased in 2020 (incidence rate ratio: 0.78; 95 % confidence interval: 0.67-0.91) and 2021 (incidence rate ratio: 0.73; 95 % confidence interval: 0.63-0.86). Lifestyle changes due to the COVID-19 pandemic affected the number of emergency transports due to acute alcohol intoxication in 2020 and 2021 (during the COVID-19 pandemic) compared to that in 2019 (before the pandemic).

Exploring Alcohol-Related Behaviours in an Adult Sample with Anorexia Nervosa and Those in Recovery

While individuals with Bulimia Nervosa (BN) and Binge Eating Disorder (BED) often present with a higher rate of Alcohol Use Disorder (AUD) than the general population, it is unclear whether this extends to AN. This cross-sectional study examined differences in alcohol-related behaviours, measured using the Alcohol Use Identification Test (AUDIT), between AN participants (n = 58), recovered AN (rec-AN) participants (n = 25), and healthy controls (n = 57). Statistical models controlled for age and ethnicity. The relationship between alcohol-related behaviours with ED psychopathology and with depression was also assessed. The findings indicated that acute AN participants were not at greater risk of AUD than healthy controls. However, rec-AN participants displayed greater total audit scores than those with acute AN, and more alcohol-related behaviours than healthy controls. Acute AN participants consumed significantly less alcohol than both the healthy control group and rec-AN group. No associations were found between ED psychopathology and alcohol-related behaviours in the AN group or rec-AN. This highlights alcohol as a potential coping mechanism following AN recovery. Clinicians should consider assessments for AUD and targeted interventions aimed at encouraging healthy coping mechanisms in this group. Future studies should look at alcohol use as a moderating factor for AN recovery.

Inhibition of ALDH2 by quercetin glucuronide suggests a new hypothesis to explain red wine headaches

The consumption of red wine induces headaches in some subjects who can drink other alcoholic beverages without suffering. The cause for this effect has been attributed to a number of components, often the high level of phenolics in red wine, but a mechanism has been elusive. Some alcohol consumers exhibit flushing and experience headaches, and this is attributed to a dysfunctional ALDH2 variant, the enzyme that metabolizes acetaldehyde, allowing it to accumulate. Red wine contains much higher levels of quercetin and its glycosides than white wine or other alcoholic beverages. We show that quercetin-3-glucuronide, a typical circulating quercetin metabolite, inhibits ALDH2 with an IC50 of 9.6 µM. Consumption of red wine has been reported to result in comparable levels in circulation. Thus, we propose that quercetin-3-glucoronide, derived from the various forms of quercetin in red wines inhibits ALDH2, resulting in elevated acetaldehyde levels, and the subsequent appearance of headaches in susceptible subjects. Human-subject testing is needed to test this hypothesis.

Alcohol Consumption, Cardiovascular-Related Conditions, and ALDH2*2 Ethnic Group Prevalence in Asian Americans

BACKGROUND

Little is known about the relationships between alcohol consumption and cardiovascular disease (CVD) and related chronic conditions in Asian Americans and how such risk relationships vary among their subgroups. We examine these relationships in Asian Americans and their moderation by ethnic prevalence of a variant the aldehyde dehydrogenase gene: ALDH2*2.

METHODS

Multiple logistic regression modeling was performed using a nationally representative sample of Asian-American adults aged 30 to 70 (n = 1,720) from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) Waves 2 (2004 to 2005) and 3 (2012 to 2013). Outcomes considered were diabetes, hypertension, high cholesterol, CVD, any of the 3 conditions (i.e., diabetes, high cholesterol, and CVD) documented to have a J-shaped relationship with drinking (CVDRC3), and any of the CVD-related conditions (ANYCVD). Demographic and socioeconomic characteristics, health insurance coverage, and other lifestyle risk factors (smoking and obesity/overweight) were adjusted. Analyses were stratified by gender.

RESULTS

Alcohol consumption level was positively associated only with hypertension in Asian males, with consuming 7 to 14 drinks per week associated with more than double the risk of lifetime abstinence. For females, alcohol consumption had a dose-response relationship with high cholesterol and CVDRC3. Membership in the higher ALDH2*2 ethnic group overall was associated with lower risk of CVD-related conditions. However, compared to abstainers in lower ALDH2*2 group, females in the higher ALDH2*2 group who consumed more than 7 drinks per week had a higher risk of diabetes, hypertension, CVDRC3, and ANYCVD.

CONCLUSIONS

Asian Americans may have increased risk of CVD-related conditions at relatively low alcohol consumption levels. Among Asian-American females, in particular, any amount of drinking may increase risk for high cholesterol or any of the CVD-related conditions previously documented to have a curvilinear relationship with drinking. These risks may be particularly elevated for those in ethnic groups with a high prevalence of ALDH2*2.

In utero alcohol exposure exacerbates endothelial protease activity from pial microvessels and impairs GABA interneuron positioning

In utero alcohol exposure can induce severe neurodevelopmental disabilities leading to long-term behavioral deficits. Because alcohol induces brain defects, many studies have focused on nervous cells. However, recent reports have shown that alcohol markedly affects cortical angiogenesis in both animal models and infants with fetal alcohol spectrum disorder (FASD). In addition, the vascular system is known to contribute to controlling gamma-aminobutyric acid (GABA)ergic interneuron migration in the developing neocortex. Thus, alcohol-induced vascular dysfunction may contribute to the neurodevelopmental defects in FASD. The present study aimed at investigating the effects of alcohol on endothelial activity of pial microvessels. Ex vivo experiments on cortical slices from mouse neonates revealed that in endothelial cells from pial microvessels acute alcohol exposure inhibits both glutamate-induced calcium mobilization and activities of matrix metalloproteinase-9 (MMP-9) and tissue plasminogen activator (tPA). The inhibitory effect of alcohol on glutamate-induced MMP-9 activity was abrogated in tPA-knockout and Grin1^flox/VeCad^cre mice suggesting that alcohol interacts through the endothelial NMDAR/tPA/MMP-9 vascular pathway. Contrasting with the effects from acute alcohol exposure, in mouse neonates exposed to alcohol in utero during the last gestational week, glutamate exacerbated both calcium mobilization and endothelial protease activities from pial microvessels. This alcohol-induced vascular dysfunction was associated with strong overexpression of the N-methyl-d-aspartate receptor subunit GluN1 and mispositioning of the Gad67-GFP interneurons that normally populate the superficial cortical layers. By comparing several human control fetuses with a fetus chronically exposed to alcohol revealed that alcohol exposure led to mispositioning of the calretinin-positive interneurons, whose density was decreased in the superficial cortical layers II-III and increased in deepest layers. This study provides the first mechanistic and functional evidence that alcohol impairs glutamate-regulated activity of pial microvessels. Endothelial dysfunction is characterized by altered metalloproteinase activity and interneuron mispositioning, which was also observed in a fetus with fetal alcohol syndrome. These data suggest that alcohol-induced endothelial dysfunction may contribute in ectopic cortical GABAergic interneurons, that has previously been described in infants with FASD.

The Effect of Smoking on the Association between Long-Term Alcohol Consumption and Dyslipidemia in a Middle-Aged and Older Population

AIMS

The joint effects of chronic alcohol consumption and smoking on dyslipidemia remain unclear in a prospective design. This study examined the effect of smoking on the association between long-term alcohol consumption and risk of incident dyslipidemia.

METHODS

A total of 4467 participants (1866 men and 2601women) aged 40-69 years without dyslipidemia were recruited at baseline. Alcohol consumption was assessed biennially using a questionnaire and classified as light, moderate or heavy drinker. Smoking status was examined at baseline and categorized into non-smokers and current smokers. Dyslipidemia was defined as the presence of one or more of following: hypertriglyceridemia (triglyceride ≥200 mg/dL), hypercholesterolemia (total cholesterol ≥240 mg/dL), low high-density lipoprotein-cholesterol (HDL-C) < 40 mg/dL, or high low-density lipoprotein cholesterol ≥160 mg/dL.

RESULTS

During a follow-up period of 12 years, 2872 (64.3%) participants developed dyslipidemia. In non-smoking men, light or moderate alcohol consumption was associated with a lower risk of incident dyslipidemia such as hypertriglyceridemia and hypercholesterolemia, whereas this association was not observed in current smoking men. Unlike non-smokers, the duration of alcohol drinking > 10 years was associated with a higher risk of hypertriglyceridemia in current smoking men (hazard ratio = 1.57, 95% confidence interval: 1.07-2.30, P = 0.020). In addition, alcohol consumption was inversely associated with low HDL-C regardless of smoking status. In women, alcohol consumption was inversely associated with dyslipidemia hypercholesterolemia and low HDL-C regardless of alcohol amount.

CONCLUSION

Smoking crucially confounds the association between long-term alcohol consumption and dyslipidemia, particularly in hypertriglyceridemia and hypercholesterolemia.

Individual differences in biological regulation: Predicting vulnerability to drug addiction, obesity, and other dysregulatory disorders

Physiological regulation is so fundamental to survival that natural selection has greatly favored the evolution of robust regulatory systems that use both reactive and preemptive responses to mitigate the disruptive impact of biological and environmental challenges on physiological function. In good health, robust regulatory systems provide little insight into the typically hidden complex array of sensor-effector interactions that accomplish successful regulation. Numerous health disorders have been traced to defective regulatory mechanisms, and generations of scientists have worked to discover ways to correct these defects and restore normal physiological function. Despite progress, numerous chronic health disorders remain resistant to treatment, and indeed for some disorders the incidence is increasing. We propose that an individual's susceptibility to acquire certain persistent dysregulatory disorders can be traced to interindividual variation in how that individual's regulatory system responds to challenges. Preexisting reliable individual differences among regulatory systems are typically unrecognized until appropriate regulatory challenges (e.g., exposure to a drug of abuse) lead to dysregulation (e.g., drug addiction). Specific characteristics of an individual's regulatory responsiveness may include etiological factors that participate in the acquisition, escalation and maintenance of health disorders characterized by dysregulation. By appropriately challenging a healthy individual's regulatory systems to identify its underlying characteristics, it is possible to ascertain whether an individual has an elevated risk for acquiring a dysregulated health condition and thereby enable strategies designed to prevent, rather than treat, the condition. This model is applied to drug addiction, and in addition we relate this approach to other dysregulated conditions such as obesity. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

ALDH2 rs671 polymorphisms and the risk of cerebral microbleeds in Chinese elderly: the Taizhou Imaging Study

Background

Cerebral microbleeds (CMBs) are more prevalent in Asian populations, and have been associated with increased risk of stroke, dementia and mortality. So far, risk factors for CMBs other than hypertension were merely known. Previous studies have shown that polymorphisms at aldehyde dehydrogenase 2 (ALDH2) gene were independently associated with the risk of stroke. Its role in CMBs, however, remains unclear. This study aimed to evaluate the associations of ALDH2 gene polymorphisms with CMBs in Chinese elderly.

Methods

Using bio-specimen and data collected at baseline survey of the population-based Taizhou Imaging Study (TIS) (phase I), we genotyped the single nucleotide polymorphisms (SNPs) at ALDH2 among 549 individuals aged 55–65 years, and rs671 was used as surrogate marker of ALDH2. CMBs were detected on brain magnetic resonance imaging (MRI), and further categorized as strictly lobar or as deep/mixed. Logistic regression models were used to evaluate the associations of the variants at ALDH2 and CMBs.

Results

CMBs were present in 103 individuals (18.8%). Forty-one point three percent participants were with ALDH2 *2 allele and 5.1% had ALDH2 *2/*2 genotype. Subjects with ALDH2 *1 allele were more likely to be drinker, have hypertension or CMBs than those with *2 allele (all P<0.05). Multivariate logistic regression model showed that the ALDH2 *1/*1 genotype was independently associated with CMBs (P=0.013), particularly for deep/mixed CMBs (P=0.008), and the association was more pronounced in men, non-drinkers or hypertension patients.

Conclusions

The results suggest that Han Chinese with ALDH2 *1/*1 genotype may be more susceptible to CMBs than those with ALDH2 *2 allele.

Genome-wide association study of alcohol dependence in male Han Chinese and cross-ethnic polygenic risk score comparison

Alcohol-related behaviors are moderately heritable and have ethnic-specific characteristics. At present, genetic studies for alcohol dependence (AD) in Chinese populations are underrepresented. We are the first to conduct a genome-wide association study (GWAS) for AD using 533 male alcoholics and 2848 controls of Han Chinese ethnicity and replicate our findings in 146 male alcoholics and 200 male controls. We then assessed genetic effects on AD characteristics (drinking volume/age onset/Michigan Alcoholism Screening Test (MAST)/Barratt Impulsiveness Scale (BIS-11)), and compared the polygenic risk of AD in Han Chinese with other populations (Thai, European American and African American). We found and validated two significant loci, one located in 4q23, with lead SNP rs2075633*ADH1B (P_discovery = 6.64 × 10^-16) and functional SNP rs1229984*ADH1B (P_discovery = 3.93 × 10^-13); and the other located in 12q24.12-12q24.13, with lead SNP rs11066001*BRAP (P_discovery = 1.63 × 10^-9) and functional SNP rs671*ALDH2 (P_discovery = 3.44 × 10^-9). ADH1B rs1229984 was associated with MAST, BIS_total score and average drinking volume. Polygenic risk scores from the Thai AD and European American AD GWAS were significantly associated with AD in Han Chinese, which were entirely due to the top two loci, however there was no significant prediction from African Americans. This is the first case-control AD GWAS in Han Chinese. Our findings demonstrate that these variants, which were highly linked with ALDH2 rs671 and ADH1B rs1229984, were significant modulators for AD in our Han Chinese cohort. A larger replication cohort is still needed to validate our findings.

Precision Psychiatry and Dual Disorders

OBJECTIVE

Addiction co-occurs with distinct pathological personality traits, other psychiatric disorders or symptoms and cognitive impairment, which are known as dual disorders or co-occurring disorders. This symptomatic high concurrency suggests that both conditions are in some ways causally linked. Research is ongoing to identify distinctive neurobehavioral mechanisms and endophenotypes that predispose individuals to compulsive drug use and other mental disorders. Research is also providing new revelations about the diverse effects of substances on individuals, including differences according to sex. Today we know that the same substance may give rise to different behavioral, affective, cognitive, and sensory effects across different individuals.

METHODS

This state-of the art review tends to address the concept of precision psychiatry and dual disorders. The PubMed database was searched for the last 15 years to identify those articles that reported neurobiological perspectives on dual disorders, addiction and other mental disorders, precision medicine, and precision psychiatry.

RESULTS

There has been considerable progress made in recent years in relation to the study of addiction and dual disorders. The concept of dual disorders attempts to capture not only the persistence of substance use and substance seeking but also the evident vulnerability of specific subpopulations to switch from controlled to compulsive drug use. Precision medicine is focused on identifying this individual vulnerability to illness as much as the individual response to treatment. Psychiatry is fully committed to this goal. Regarding addiction, essential precision medicine advances will be possible if concerted efforts are made in the discovery of biological variations and environmental factors that contribute to individual vulnerability to addictive disorders and dual disorders, together with the identification of moderators of treatment response.

CONCLUSIONS

Here we survey the discoveries, future research directions, and translational relevance of the concept of precision psychiatry for dual disorders. The review may offer new perspectives on this issue and highlight a new way to see and to think about dual disorders.

Commentary: Perspectives on alcohol-related gene and environment interplay in diverse populations

BACKGROUND AND OBJECTIVES

Racial/ethnic groups comprise more than 20% of the U.S. population, but many experience disproportionately high risk for alcohol misuse, often resulting in higher rates of alcohol-associated consequences. Completion of mapping the human genome has launched rapidly evolving research methods aimed at improved understanding of genetic contribution to disease. Despite decades of research on the influence of genetic and environmental risks on alcohol use disorders and outcomes, few studies have included racial/ethnic subpopulations in sufficient numbers to allow for proper statistical analysis.

METHODS

The papers in this special issue help to elucidate current knowledge on the etiology of genetic and environmental contributors and potential moderators of alcohol use and associated problems among racial/ethnic populations. The lack of racial/ethnic diversity across many genetic studies contributes to challenges in interpretation of findings and eventually applications to precision medicine.

RESULTS

Proposed approaches to overcome disparities in racial/ethnic participant recruitment in genetic studies include methods to address population stratification in allele frequency, improve transparency in subjects' consenting to participate, and engaging interdisciplinary research teams and community involvement to improve recruitment of racial/ethnic minorities.

DISCUSSION AND CONCLUSIONS

The reviews presented underscore various gaps in our knowledge of the genetic influences on alcohol use disorders due to the failure to include racially and ethnically diverse populations in genetic and epigenetic study samples. New directions are suggested to overcome the resulting research challenges and ultimately to inform future personalized intervention approaches for racial/ethnic populations.

SCIENTIFIC SIGNIFICANCE

Inclusion of heterogeneous populations in genomic research will provide a better comprehension of possible unique genetic factors in the broader general population that may be missed due to exclusion of unique and common variants that may be present in racial/ethnic populations. (Am J Addict 2017;26:526-531).

Conclusion: Special issue on genetic and alcohol use disorder research with diverse racial/ethnic groups: Key findings and potential next steps

BACKGROUND AND OBJECTIVES

This special issue brings together papers focusing on a wide range of topics relevant to the research and understanding of the role of race/ethnicity and genetic variation for the susceptibility of developing an alcohol use disorder (AUD).

METHODS

The key findings from the issue's 10 articles are reviewed and organized here around three topics: I: addictive behaviors and potential environmental influences; II: a focus on four racial/ethnic groups; and III: special methodologies.

RESULTS

Several potential next steps in improving effective research strategies are highlighted: (1) implementing best practices for outreach and community engagement may reduce reluctance to participate; (2) recruiting adequately sized and racially/ethnically diverse samples will require new collaborations with investigators who successfully work in diverse communities; (3) identifying and assessing environmental influences that are both unique to, and common among, racial/ethnic groups may inform preventions for AUD; (4) use of standardized measures will facilitate the generation of larger samples and meta-analysis of research findings; and (5) use of better analytic approaches and experimental methods will improve replication in gene finding research and help advance new areas of research.

CONCLUSIONS

Genetic research of AUD in diverse racial/ethnic populations is advancing. The articles in this issue examined the general theme of including diverse population groups in genetic studies and offered potential strategies for addressing some common problems.

SCIENTIFIC SIGNIFICANCE

Greater inclusion of diverse racial/ethnic populations in this research is important to ensure that the benefits of new knowledge and technology are equally shared. (Am J Addict 2017;26:532-537).

Associations Between Genomic Variants in Alcohol Dehydrogenase Genes and Alcohol Symptomatology in American Indians and European Americans: Distinctions and Convergence

BACKGROUND

Higher rates of alcohol use disorders (AUD) have been observed in some Native American populations than other ethnic groups such as European Americans (EAs) in the United States. Previous studies have shown that variation in the alcohol dehydrogenase (ADH) genes may affect the risk for development of AUD and that the prevalence of these variants differs depending on the ancestral origins of a population.

METHODS

In this study, we assessed sequencing variants in the ADH genomic region (ADH1-7) and tested for their associations with AUD phenotypes in 2 independent populations: an American Indian (AI) community sample and an EA cohort from the San Francisco Family Alcohol Study. Association tests were conducted for both common and rare variants using sequencing data for 2 phenotypes: the number of alcohol-related life events and the count of alcohol dependence drinking symptoms. A regularized regression method was used to select the best set of ADH variants associated with phenotypes. Variance component model was incorporated in all analyses to leverage the admixture and relatedness.

RESULTS

Two variants near ADH4 and 2 near ADH1C exhibited significant associations with AUD in AIs; no variant was significant in EAs. Common risk variants in AIs were either absent from or much less frequent in EAs. The feature selection method selected mostly distinct yet often colocated subsets of ADH variants to be associated with AUD phenotypes between the 2 cohorts. In the rare-variant analyses, the only association was observed between the whole region and the alcohol-related life events in AIs.

CONCLUSIONS

Our results suggest that ADH variants, both common and rare, are more likely to impact risk for alcohol-related symptomatology in this AI population than in this EA sample, and ADH variants that might affect AUD are likely different but convergent on similar regions between the 2 populations.

Introduction: Special issue on genetic research of alcohol use disorder in diverse racial/ethnic populations

This special issue of The American Journal on Addictions is an extension of a workshop held at the Research Society on Alcoholism (2015) highlighting several important issues related to studies of the genetic bases of alcohol use disorder among racially/ethnically diverse populations. While not exhaustive in their coverage, the papers in this special issue focus on three important topics: (1) the importance of considering the social and environmental context in genetic analyses; (2) social and cultural considerations for engaging diverse communities in genetic research; and (3) methodologies related to phenotype development for use with racially/ethnically diverse populations. A brief overview of each paper included in these three sections is presented. The issue concludes with additional considerations for genetic research with racially/ethnically diverse population groups along with a commentary. (Am J Addict 2017;26:422-423).