The contribution of polymorphism in the alcohol dehydrogenase beta subunit to alcohol sensitivity in a Japanese population

Associations of ADH1B and ALDH2 genotypes and alcohol flushing with drinking history, withdrawal symptoms, and ICD-10 criteria in Japanese alcohol-dependent men

OBJECTIVES

Given the high prevalence of fast-metabolizing alcohol dehydrogenase-1B*2 (ADH1B*2 ) and inactive aldehyde dehydrogenase-2*2 (ALDH2*2 ) alleles in East Asians, we evaluated how the ADH1B / ALDH2 genotypes and alcohol flushing might affect the development of alcohol dependence (AD).

METHODS

We evaluated how the ADH1B / ALDH2 genotypes and self-reported alcohol flushing affected history of drinking events and withdrawal symptoms and ICD-10 criteria in 4116 Japanese AD men.

RESULTS

The ADH1B*1/*1 group and ALDH2*1/*1 group were 1-5 years younger than the ADH1B*2 (+) and ALDH2*1/*2 groups, respectively, for all of the ages at onset of habitual drinking, blackouts, daytime drinking, uncontrolled drinking, withdrawal symptoms, and first treatment for AD, and the current age. Blackouts were more common in the ADH1B*1/*1 group and ALDH2*1/*1 group. Daytime drinking, uncontrolled drinking, and withdrawal symptoms, such as hand tremor, sweating, convulsions, and delirium tremens/hallucinations were more common in the ADH1B*1/*1 group. The ADH1B*1/*1 was positively associated with the ICD-10 criteria for 'tolerance' and 'withdrawal symptoms'. The ADH1B*1/*1 group and ALDH2*1/*2 group had a larger ICD-10 score. Never flushing was reported by 91.7% and 35.2% of the ALDH2*1/*1 and ALDH2*1/*2 carriers, respectively. After a 1-2-year delay in the onset of habitual drinking in the former-/current-flushing group, no differences in the ages of the aforementioned drinking milestones were found according to the flushing status.

CONCLUSION

The ADH1B*1/*1 and ALDH2*1/*1 accelerated the development of drinking events and withdrawal symptoms in Japanese AD patients. ICD-10 score was larger in the ADH1B*1/*1 group and ALDH2*1/*2 group. The effects of alcohol flushing on drinking events were limited.

Effectiveness of genetic feedback on alcohol metabolism to reduce alcohol consumption in young adults: an open-label randomized controlled trial

BACKGROUND

It is unclear whether brief interventions using the combined classification of alcohol-metabolizing enzymes aldehyde dehydrogenase 2 (ALDH2) and alcohol dehydrogenase 1B (ADH1B) together with behavioral changes in alcohol use can reduce excessive alcohol consumption. This study aimed to examine the effects of a brief intervention based on the screening of ALDH2 and ADH1B gene polymorphisms on alcohol consumption in Japanese young adults.

METHODS

In this open-label randomized controlled trial, we enrolled adults aged 20-30 years who had excessive drinking behavior (average amount of alcohol consumed: men, ≥  4 drinks/per day and women, ≥  2 drinks/per day; 1 drink = 10 g of pure alcohol equivalent). Participants were randomized into intervention or control group using a simple random number table. The intervention group underwent saliva-based genotyping of alcohol-metabolizing enzymes (ALDH2 and ADH1B), which were classified into five types. A 30-min in-person or online educational counseling was conducted approximately 1 month later based on genotyping test results and their own drinking records. The control group received traditional alcohol education. Average daily alcohol consumption was calculated based on the drinking diary, which was recorded at baseline and at 3 and 6 months of follow-up. The primary endpoint was average daily alcohol consumption, and the secondary endpoints were the alcohol-use disorder identification test for consumption (AUDIT-C) score and behavioral modification stages assessed using a transtheoretical model.

RESULTS

Participants were allocated to the intervention (n = 100) and control (n = 96) groups using simple randomization. Overall, 28 (29.2%) participants in the control group and 21 (21.0%) in the intervention group did not complete the follow-up. Average alcohol consumption decreased significantly from baseline to 3 and 6 months in the intervention group but not in the control group. The reduction from baseline alcohol consumption values and AUDIT-C score at 3 months were greater in the intervention group than in the control group (p < 0.001). In addition, the behavioral modification stages were significantly changed by the intervention (p < 0.001).

CONCLUSIONS

Genetic testing for alcohol-metabolizing enzymes and health guidance on type-specific excessive drinking may be useful for reducing sustained average alcohol consumption associated with behavioral modification.

TRIAL REGISTRATION

R000050379, UMIN000044148, Registered on June 1, 2021.

Understanding and applying gene-environment interactions: a guide for nutrition professionals with an emphasis on integration in African research settings

Noncommunicable diseases (NCDs) are influenced by the interplay between genetics and environmental exposures, particularly diet. However, many healthcare professionals, including nutritionists and dietitians, have limited genetic background and, therefore, they may lack understanding of gene-environment interactions (GxEs) studies. Even researchers deeply involved in nutrition studies, but with a focus elsewhere, can struggle to interpret, evaluate, and conduct GxE studies. There is an urgent need to study African populations that bear a heavy burden of NCDs, demonstrate unique genetic variability, and have cultural practices resulting in distinctive environmental exposures compared with Europeans or Americans, who are studied more. Although diverse and rapidly changing environments, as well as the high genetic variability of Africans and difference in linkage disequilibrium (ie, certain gene variants are inherited together more often than expected by chance), provide unparalleled potential to investigate the omics fields, only a small percentage of studies come from Africa. Furthermore, research evidence lags behind the practices of companies offering genetic testing for personalized medicine and nutrition. We need to generate more evidence on GxEs that also considers continental African populations to be able to prevent unethical practices and enable tailored treatments. This review aims to introduce nutrition professionals to genetics terms and valid methods to investigate GxEs and their challenges, and proposes ways to improve quality and reproducibility. The review also provides insight into the potential contributions of nutrigenetics and nutrigenomics to the healthcare sphere, addresses direct-to-consumer genetic testing, and concludes by offering insights into the field's future, including advanced technologies like artificial intelligence and machine learning.

An idea to explore: Determination of single nucleotide polymorphisms in alcohol metabolism-related genes using PCR-based assays to understand the link between an individual's genotype and phenotype

Here, we propose a laboratory exercise to quickly determine single nucleotide polymorphisms (SNPs) in human alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2) genes involved in alcohol metabolism. In this exercise, two different genotyping methods based on polymerase chain reaction (PCR), namely allele-specific (AS) PCR and a PCR-restriction fragment polymorphism (RFLP) analysis, can be performed under the same PCR program (2-step × 35 cycles, 35 min total) in parallel using a hair root lysate as a template. In AS-PCR, the target regions of the G- or A-alleles of both genes are allele-specifically amplified in a single PCR tube. In the PCR-RFLP analysis, the two genes are amplified simultaneously in a single tube, and then a portion of the PCR product is double-digested with restriction enzymes MslI and Eam1104I for 5 min. The resulting reaction products of each method are electrophoresed side by side, and the genotypes are determined from the DNA band patterns. With the optimized protocol, the whole process from template preparation to genotyping can be completed in about 75 min. During PCR, students also perform an ethanol patch test to estimate their ability to metabolize alcohol. This series of experiments can help students learn the principles and applications of PCR/SNP analyses. By comparing the genotypes revealed by PCR and the phenotypes revealed by the patch tests, students can gain a better understanding of the clinical value of genetic testing.

Genetic interactions drive heterogeneity in causal variant effect sizes for gene expression and complex traits

Despite the growing number of genome-wide association studies (GWASs), it remains unclear to what extent gene-by-gene and gene-by-environment interactions influence complex traits in humans. The magnitude of genetic interactions in complex traits has been difficult to quantify because GWASs are generally underpowered to detect individual interactions of small effect. Here, we develop a method to test for genetic interactions that aggregates information across all trait-associated loci. Specifically, we test whether SNPs in regions of European ancestry shared between European American and admixed African American individuals have the same causal effect sizes. We hypothesize that in African Americans, the presence of genetic interactions will drive the causal effect sizes of SNPs in regions of European ancestry to be more similar to those of SNPs in regions of African ancestry. We apply our method to two traits: gene expression in 296 African Americans and 482 European Americans in the Multi-Ethnic Study of Atherosclerosis (MESA) and low-density lipoprotein cholesterol (LDL-C) in 74K African Americans and 296K European Americans in the Million Veteran Program (MVP). We find significant evidence for genetic interactions in our analysis of gene expression; for LDL-C, we observe a similar point estimate, although this is not significant, most likely due to lower statistical power. These results suggest that gene-by-gene or gene-by-environment interactions modify the effect sizes of causal variants in human complex traits.

Combinations of alcohol-induced flushing with genetic polymorphisms of alcohol and aldehyde dehydrogenases and the risk of alcohol dependence in Japanese men and women

OBJECTIVE

The risk of alcohol dependence (AD) in Japanese men and women was evaluated according to combinations of alcohol flushing and aldehyde dehydrogenase-2 (ALDH2, rs671) and alcohol dehydrogenase-1B (ADH1B, rs1229984) genotypes, all of which are known to determine AD susceptibility in Asians. Previous studies have focused on men, since women account for a smaller proportion of AD subjects.

METHODS

Case control studies were conducted between 3721 male and 335 female AD Japanese and 610 male and 406 female controls who were asked about their current or former tendency to experience facial flushing after drinking a glass of beer and underwent ALDH2 and ADH1B genotyping. The time at which alcohol-induced facial flushing tendencies had disappeared in former-flushing AD subjects was also evaluated.

RESULTS

Current alcohol flushing, the inactive ALDH2*1/*2 genotype, and the fast-metabolizing ADH1B*2 allele were less frequently found in the AD groups. Although alcohol flushing was strongly influenced by the ALDH2 and ADH1B genotypes, multiple logistic model showed that never or former flushing and the genotype combinations were independent strong risk factors of AD in men and women. Never or former flushing (vs. current flushing) markedly increased the odds ratios of AD in carriers of each of the ALDH2 and ADH1B genotype combinations. The temporal profiles for drinking and flushing in former-flushing AD subjects revealed that the flushing response disappeared soon after or before the start of habitual drinking during young adulthood, regardless of the ALDH2 genotype.

CONCLUSION

Although alcohol flushing is influenced by the ALDH2 and ADH1B genotypes, constitutional or acquired flushing tolerance is an independent susceptibility trait for AD. The combination of the alcohol flushing status and the ALDH2 and ADH1B genotypes can provide a better new strategy for AD risk assessment than the alcohol flushing status alone or the genotypes alone in Asian men and women.

Effects of daily alcohol intake on glomerular filtration rate over three years

Background:

The association between daily alcohol intake and changes in renal function in the Japanese general population is not well established.

Methods:

We analyzed data from 150 residents who underwent specific health checkups held in Mishima Town in 2016 and 2019. We divided participants on the basis of alcohol consumption: residents with daily alcohol intake of < 20 g/day (the none-to-low group, n = 104, 69.3%); those with daily alcohol intake of ≥ 20 but < 40 g/day (the intermediate group, n = 30, 20.0%); and those with daily alcohol intake of ≥ 40 g/day (the high group, n = 16, 10.7%). We compared baseline characteristics. The primary endpoint was a decrease in estimated glomerular filtration rate (eGFR), defined as the decrease in eGFR greater than the median decrease over three years.

Results:

The three-year changes in eGFR were +0.3 (−4.8, +3.0), −2.3 (−5.1, +1.2), and −4.9 (−8.2, −2.9) mL/min/1.73 m² in the none-to-low, intermediate, and high groups, respectively (P = 0.007). In the multivariate logistic regression analysis, a high amount of alcohol intake was independently associated with a decrease in eGFR, with adjusted odds ratio of 11.418 (95% confidence interval 1.554-83.879, P = 0.017).

Conclusion:

A high average daily alcohol intake is associated with a decrease in eGFR.

Impacts of interactions between ADH1B and ALDH2 genotypes on alcohol flushing, alcohol reeking on the day after drinking, and age distribution in Japanese alcohol-dependent men

OBJECTIVE

This study sought to evaluate the impacts of interactions between the alcohol dehydrogenase-1B (rs1229984) genotype and the aldehyde dehydrogenase-2 (rs671) genotype on alcohol flushing, alcohol reeking on the day after drinking, and the age distribution in alcohol-dependent patients.

METHODS

The study subjects were 4107 Japanese alcohol-dependent men who underwent alcohol dehydrogenase-1B and aldehyde dehydrogenase-2 genotyping: 4051 patients were asked about their current or former tendency to experience facial flushing after drinking a glass of beer, and 969 patients were asked about whether they had ever been told that they reeked of alcohol more than 12 hours after they had stopped drinking.

RESULTS

Current, former, and never flushing were reported in 3.5, 14.9, and 81.5%, respectively, of the subject, and alcohol reeking after more than 12 hours in 36.1% of the subjects. The fast-metabolizing ADH1B*2(+) genotype (*1/*2 or *2/*2) and the inactive ALDH2*2(+) genotype (*1/*2 or *2/*2) affected the multivariate odds ratios for current or former flushing [odds ratio, 95% confidence interval = 2.27 (1.79-2.86) and 23.0 (18.6-28.5), respectively, vs. *2(-) genotype] and for alcohol reeking [0.39 (0.29-0.52) and 1.56 (1.09-2.25), respectively, vs. *2(-) genotype]. An age-dependent decrease in the ADH1B*2(-) and ALDH2*2(-) combination from 32.3% in the 30-39-year age group to 12.5% in the 70-79-year age group and an age-dependent increase in the ADH1B*2(+) and ALDH2*2(-) combination from 52.5% in the 30-39-year age group to 70.5% in the 70-79-year age group were observed (P < 0.0001 for trend). The frequencies of the ADH1B*2(-) and ALDH2*2(+) combination (4.7-6.2%) and the ADH1B*2(+) and ALDH2*2(+) combination (8.9-12.0%) did not change markedly with increasing age.

CONCLUSION

Interactions between the alcohol dehydrogenase-1B and aldehyde dehydrogenase-2 genotypes modified alcohol flushing, alcohol reeking on the day after drinking, and the age distribution. These findings support the protective roles of the ADH1B*2(+) and ALDH2*2(+) genotypes against the development of alcohol dependence.

Genetics and functions of the retinoic acid pathway, with special emphasis on the eye

Retinoic acid (RA) is a potent morphogen required for embryonic development. RA is formed in a multistep process from vitamin A (retinol); RA acts in a paracrine fashion to shape the developing eye and is essential for normal optic vesicle and anterior segment formation. Perturbation in RA-signaling can result in severe ocular developmental diseases—including microphthalmia, anophthalmia, and coloboma. RA-signaling is also essential for embryonic development and life, as indicated by the significant consequences of mutations in genes involved in RA-signaling. The requirement of RA-signaling for normal development is further supported by the manifestation of severe pathologies in animal models of RA deficiency—such as ventral lens rotation, failure of optic cup formation, and embryonic and postnatal lethality. In this review, we summarize RA-signaling, recent advances in our understanding of this pathway in eye development, and the requirement of RA-signaling for embryonic development (e.g., organogenesis and limb bud development) and life.

Functional variants in ADH1B and ALDH2 are non-additively associated with all-cause mortality in Japanese population

The functional variants involved in alcohol metabolism, the A allele of rs1229984:A > G in ADH1B and the A allele of rs671:G > A in ALDH2, are specifically prevalent among East Asian population. They are shown to be under recent positive selection, but the reasons for the selection are unknown. To test whether these positively selected variants have beneficial effects on survival in modern population, we performed the survival analyses using the large-scale Japanese cohort (n = 135,974) with genotype and follow-up survival data. The rs671-A allele was significantly associated with the better survival in the additive model (HR for mortality = 0.960, P = 1.7 × 10⁻⁵), and the rs1229984-A had both additive and non-additive effects (HR = 0.962, P = 0.0016 and HR = 0.958, P = 0.0066, respectively), which was consistent with the positive selection. The favorable effects of these alleles on survival were independent of the habit of alcohol consumption itself. The heterogenous combinatory effect between rs1229984 and rs671 genotype was also observed (HRs for AA genotype at rs671 were 1.03, 0.80, and 0.90 for GG, GA, and AA genotype at rs1229984, respectively), supposedly reflecting the synergistic effects on survival.

Impact of Diarrhea after Drinking on Colorectal Tumor Risk: A Case Control Study

Background:

Recently, the number of colorectal cancer (CRC) cases in Japan has been increasing, and is strongly influenced by alcohol consumption. On the other hand, there are several reports suggesting a relationship between bowel movement (constipation and diarrhea) and CRC development. Moreover, it is generally known that diarrhea may occur after drinking. However, the mechanism by which drinking alcohol increases CRC is not fully clarified yet. We hypothesized that diarrhea after drinking may play an important role in colorectal carcinogenesis.

Methods:

We examined the presence of diarrhea after drinking and further evaluated the correlation of diarrhea after drinking with the incidence of colorectal tumors. To obtain the status of the feces, a self-recorded questionnaire survey was administered using the dietary-recording method. Blood samples were obtained to analyze the ALDH2 Glu504Lys and ADH1B His48Arg polymorphisms.

Results:

The participants were 417 patients who had undergone a total colonoscopy. The control was selected from 186 patients who underwent a medical checkup at the same hospital during the same time period. The odds ratio for all subjects was 2.1 (95% CI: 1.18 - 3.80), and that for heavy drinkers was 4.2 (1.48 - 11. 90).

Conclusions:

The results demonstrated that those who have diarrhea after drinking possess a high risk of developing colon tumors.

Primary Reason for Drinking Among Current, Former, and Never Flushing College Students

Alcohol consumption among individuals who experience a flushing response (reddening of the face, nausea, dizziness, headache, anxiety, and increased heartbeat) can result in serious health problems. However, studies on reasons for drinking among flushers, especially in the college context, are limited. Thus, this study investigated the association between primary reason for drinking and alcohol use among a nationally representative sample of current, former, and never flushing college students. The aim was to measure whether college students with current or former experience of facial flushing have different primary reasons for drinking compared to students with no experience of facial flushing. We surveyed and analyzed the data of 4590 students in a nationally representative sample of 82 colleges in South Korea. Multiple regression analysis was used to identify the association between primary reason for drinking and alcohol intake. Alcohol intake was measured using the Alcohol Use Disorders Identification Test (AUDIT). Among 1537 current (33.5%), 152 former (3.3%), and 2901 (63.2%) never flushers, mean AUDIT scores were 7.715 ± 5.434, 11.039 ± 6.405, and 10.465 ± 5.779, respectively. Current flushers had significantly higher AUDIT scores when drinking for pleasure (β = 2.696, p < 0.0001) or stress/depression (β = 2.578, p < 0.0001). Primary reasons for drinking were not associated with alcohol intake for former flushers. Never flushers had significantly higher AUDIT scores when drinking for pleasure (β = 2.696, p < 0.0001), stress/depression (β = 2.578, p < 0.0001), or boredom (β = 0.740, p = 0.029) than peer pressure. Our results suggest that former and never flushers consume higher amounts of alcohol on average than never flushers. For current flushers, drinking for pleasure or stress/depression may increase alcohol intake, while for never flushers, drinking for pleasure, stress/depression, as well as boredom may have the same effect.

Alcohol Dehydrogenases, Aldehyde Dehydrogenases, and Alcohol Use Disorders: A Critical Review

Alcohol use disorders (AUDs) are complex traits, meaning that variations in many genes contribute to the risk, as does the environment. Although the total genetic contribution to risk is substantial, most individual variations make only very small contributions. By far the strongest contributors are functional variations in 2 genes involved in alcohol (ethanol [EtOH]) metabolism. A functional variant in alcohol dehydrogenase 1B (ADH1B) is protective in people of European and Asian descent, and a different functional variant in the same gene is protective in those of African descent. A strongly protective variant in aldehyde dehydrogenase 2 (ALDH2) is essentially only found in Asians. This highlights the need to study a wide range of populations. The likely mechanism of protection against heavy drinking and AUDs in both cases is alteration in the rate of metabolism of EtOH that at least transiently elevates acetaldehyde. Other ADH and ALDH variants, including functional variations in ADH1C, have also been implicated in affecting drinking behavior and risk for alcoholism. The pattern of linkage disequilibrium in the ADH region and the differences among populations complicate analyses, particularly of regulatory variants. This critical review focuses upon the ADH and ALDH genes as they affect AUDs.

Alcohol metabolism and oesophageal cancer: a systematic review of the evidence

Alcohol is a major risk factor for oesophageal squamous cell carcinoma (OSCC), the most prevalent histological subtype of oesophageal cancer (OC) worldwide. The metabolism of alcohol is regulated by specific enzymes whose activity and expression is influenced by genetic polymorphisms. We conducted a systematic review of current epidemiological evidence of the relationship between alcohol intake and OC risk, including the role of tobacco smoking and functional polymorphisms of alcohol dehydrogenases (ADHs) and aldehyde dehydrogenases (ALDHs). Potential biological mechanisms underlying oesophageal carcinogenesis are also discussed. Frequency and intensity of alcohol intake have been consistently associated with an increased risk of OSCC in regions with low and high incidence of the disease. The highest risk was reported among tobacco smokers, whereas the association between alcohol and OSCC risk was weak in the absence of tobacco use. The ADH1B, ADH1C and ALDH2 gene polymorphisms influence the risk of OSCC through modulation of acetaldehyde metabolism and propensity to alcohol intake. These functional variants may be suitable proxies of alcohol exposure for use in Mendelian randomization studies if complemented by reported alcohol intake data. Recent epidemiological and experimental studies investigating the role of alcohol consumption in OC development have implicated the microbiome as a new promising avenue for research, which entail novel potential mechanisms of alcohol-related oesophageal carcinogenesis. Microbial communities associated with alcohol consumption might be used as biomarkers to raise the potential of intervening among susceptible individuals.

A Bayesian Approach for Population Pharmacokinetic Modeling of Alcohol in Japanese Individuals

Background

Blood alcohol concentration data that were previously obtained from 34 healthy Japanese subjects with limited sampling times were reanalyzed. Characteristics of the data were that the concentrations were obtained from only the early part of the time-concentration curve.

Objective

To explore significant covariates for the population pharmacokinetic analysis of alcohol by incorporating external data using a Bayesian method, and to estimate effects of the covariates.

Methods

The data were analyzed using a Markov chain Monte Carlo Bayesian estimation with NONMEM 7.3 (ICON Clinical Research LLC, North Wales, Pennsylvania). Informative priors were obtained from the external study.

Results

A 1-compartment model with Michaelis-Menten elimination was used. The typical value for the apparent volume of distribution was 49.3 L at the age of 29.4 years. Volume of distribution was estimated to be 20.4 L smaller in subjects with the ALDH2*1/*2 genotype than in subjects with the ALDH2*1/*1 genotype.

Conclusions

A population pharmacokinetic model for alcohol was updated. A Bayesian approach allowed interpretation of significant covariate relationships, even if the current dataset is not informative about all parameters. This is the first study reporting an estimate of the effect of the ALDH2 genotype in a PPK model.

Recovery from anemia and leukocytopenia after abstinence in Japanese alcoholic men and their genetic polymorphisms of alcohol dehydrogenase-1B and aldehyde dehydrogenase-2

BACKGROUND

The combination of the fast-metabolizing alcohol dehydrogenase-1B (ADH1B*2 allele) and inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/*2) increases susceptibility to macrocytic anemia and leukocytopenia in alcoholics due to severe acetaldehydemia. More than half of Japanese drinkers with esophageal cancer have this genotype combination.

METHODS

To assess the recovery of hematologic abnormalities after drinking cessation, changes in blood erythrocyte indices and leukocyte count during 8-week hospital stay were evaluated in 925 Japanese alcoholic men. We used four categories in ascending order for high blood acetaldehyde exposure from drinking: A, ADH1B*1/*1 plus ALDH2*1/*1; B, ADH1B*2 plus ALDH2*1/*1; C, ADH1B*1/*1 plus ALDH2*1/*2; and D, ADH1B*2 plus ALDH2*1/*2.

RESULTS

Mean values of hemoglobin and hematocrit were the lowest, and those of mean corpuscular volume (MCV) were markedly the highest in the D group on admission, and returning toward normal after abstinence, but the inter-group differences remained significant throughout the 8 weeks. The mean leukocyte count was the lowest in the D group on admission, but increased during 4-week abstinence when the inter-group differences were no longer significant. Frequencies of MCV ≥110 fl (50.5%), hemoglobin levels <11.5 g/dL (32.7%), hemoglobin levels <10.0 g/dL (9.9%) and leukocytopenia <4000/μL (22.8%) were the highest in the D group on the admission day and decreased at the 4-week abstinence (28.7%, 18.8%, 4.0% and 7.9%, respectively). The inter-group differences in frequencies of the severe anemia and leukocytopenia disappeared after 4-week abstinence.

CONCLUSIONS

Drinking cessation before surgery and/or chemoradiation treatment for esophageal cancer may be effective for recovery from anemia and leukocytopenia in drinkers belonging to the D group.

[Associations between ALDH2 and ADH1B Genotypes and Ethanol-Induced Cutaneous Erythema in Young Japanese Women]

OBJECTIVES

The purpose of this study was to identify associations between ALDH2 and ADH1B genotypes and ethanol-induced cutaneous erythema and assess the accuracy of an ethanol patch test in young Japanese women.

METHODS

The subjects were 942 female Japanese university students. They were given an ethanol patch test and examined for ethanol-induced cutaneous erythema both immediately after removing the patch and 10 minutes after removing the patch. A saliva sample was used to determine the ALDH2 and ADH1B genotype of each subject by realtime PCR.

RESULTS

The sensitivity and specificity of erythema immediately after removing the patch as the marker for the presence of inactive ALDH2 were 69.6% and 87.7%, respectively, and the sensitivity and specificity of erythema 10 minutes after removing the patch were 85.2% and 85.1%, respectively. The sensitivity of erythema after 10 minutes was markedly lower in the ADH1B*1/*1 carriers than in the ADH1B*2 carriers (8.3% vs. 89.7%, p<0.0001), and the specificity was significantly higher in the ADH1B*1/*1 carriers than in the ADH1B*2 carriers (96.9% vs. 84.3%, p<0.05).

CONCLUSIONS

Overall, both sensitivity and specificity were satisfactorily high, but having the ADH1B*1/*1 genotype prevented a positive reaction for inactive ALDH2 and caused false-negative results. The data also suggested that having the ADH1B*2/*2 genotype caused a positive reaction in subjects with the ALDH2*1/*1 genotype. Despite these exceptions, the ethanol patch test has enough accuracy and can be used easily to subjects who don't drink alcohol. This is a valuable tool for improving the health literacy of younger generation subjects.

Relationships of alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2) genotypes with alcohol sensitivity, drinking behavior and problem drinking in Japanese older men

OBJECTIVES

Many East Asians have the genetic polymorphisms rs1229984 in alcohol dehydrogenase 1B (ADH1B) and rs671 in aldehyde dehydrogenase 2 (ALDH2). Here we analyzed the relationships of the two genotypes with alcohol sensitivity, drinking behavior and problem drinking among older and younger men living in rural areas of Japan.

METHODS

The subjects were 718 Japanese men aged 63.3 ± 10.8 (mean ± SD), categorized into the older (≥65 years, n = 357) and younger (<65 years, n = 361) groups. Facial flushing frequency, drinking behavior and positive CAGE results were compared among the genotypes using Bonferroni-corrected χ(2) test and a multivariate logistic regression analysis adjusting for age, BMI and lifestyle factors.

RESULTS

The frequency of 'always' facial flushing among the ADH1B*1/*2 carriers was significantly lower than that among the ADH1B*2/*2 carriers in the older group (P < 0.01). The alcohol consumption (unit/day) in the ADH1B*1/*2 carriers tended to be higher compared with that in the ADH1B*2/*2 carriers among the older group (P = 0.050). In the younger group, no significant differences in alcohol sensitivity and drinking habits were generally found among the ADH1B genotypes. The ADH1B*1/*1 genotype tended to be positively associated with problem drinking in the older group (P = 0.080) but not in the younger group. The ALDH2 genotypes consistently and strongly affected the alcohol sensitivity, drinking behavior and problem drinking in both the younger and older group.

CONCLUSIONS

We for the first time observed a significant difference in alcohol sensitivity between ADH1B*1/*2 and ADH1B*2/*2 in older men aged 65 and above.

ALDH2*2 but not ADH1B*2 is a causative variant gene allele for Asian alcohol flushing after a low-dose challenge: correlation of the pharmacokinetic and pharmacodynamic findings

OBJECTIVE

It has been well documented that variant alleles of both ADH1B*2 of alcohol dehydrogenase (ADH) and ALDH2*2 of aldehyde dehydrogenase (ALDH) protect against the development of alcoholism in East Asians. However, it remains unclear whether ADH1B*2 contributes significantly toward the accumulation of systemic blood acetaldehyde and whether it plays a critical role in the alcohol flushing reaction.

PARTICIPANTS AND METHODS

Sixty-one adult Han Chinese men were recruited and divided into six combinatorial genotypic groups: ALDH2*1/*1-ADH1B*1/*1 (12), ALDH2*1/*1-ADH1B*1/*2 (11), ALDH2*1/*1-ADH1B*2/*2 (11); ALDH2*1/*2-ADH1B*1/*1 (9), ALDH2*1/*2-ADH1B*1/*2 (9), and ALDH2*1/*2-ADH1B*2/*2 (9). After ingesting 0.3 g/kg of alcohol, blood ethanol, acetaldehyde, and acetate concentrations, as well as the facial skin blood flow (FSBF) and pulse rate were measured for 130 min.

RESULTS

The ALDH2*1/*2 heterozygotes carrying three ADH1B allelotypes showed significantly higher peak levels and areas under the concentration curve (AUCs) of the blood acetaldehyde as well as significantly greater increases in the peak pulse rate and peak FSBF compared with the ALDH2*1/*1 homozygotes. However, no significant differences in peak levels and AUCs of blood ethanol, acetaldehyde or acetate, or the peak cardiovascular responses, were found between the ADH1B allelotypes carrying ALDH2*1/*1 or between those with ALDH2*1/*2. Partial correlation analyses showed that peak blood acetaldehyde, rather than the blood ethanol or acetate, was correlated significantly with the peak responses of pulse rate and FSBF.

CONCLUSION

Findings indicate that ALDH2*2, rather than ADH1B2*2, is a causal variant allele for the accumulation of blood acetaldehyde and the resultant facial flushing during low alcohol consumption.

Genetic alcohol sensitivity regulated by ALDH2 and ADH1B polymorphisms is strongly associated with depression and anxiety in Japanese employees

BACKGROUND

Although alcohol-related disorders (ARD) have been shown to be accompanied by comorbid depressive and anxiety disorders, and alcohol metabolic enzyme genes, ADH1B and ALDH2 polymorphisms, have been associated with an increased risk of ARD, no studies have been conducted to evaluate the associations between these genetic polymorphisms and anxiety or depression.

METHOD

A total of 1944 Japanese workers were interviewed regarding their depressive and anxiety disorders, including suicidality, by a brief psychiatric structured interview (MINI). We investigated the relationship of ADH1B rs1229984 and ALDH2 rs671 polymorphism combinations with mental disorder risks. Logistic regression analysis was used to evaluate the associations between those polymorphisms and anxiety/depressive disorders, adjusting for sex, age, and job rank. The degree of alcohol sensitivity was classified into five groups according to the combination of two enzyme genotypes (Group I-V, in order from the lowest alcohol sensitivity).

RESULTS

Those with ALDH2(*)1/(*)1 and ADH1B(*)1/(*)1 were likely to be at an increased risk of depressive and anxiety disorders as well as ARD. This tendency was more apparent among non-drinkers (OR 9.20, 95% CI 1.66-50.89). No adverse effects of ALDH2 or ADH1B alone were observed with mental disorder risks. Likewise, analyses conducted combining job rank and genetic alcohol sensitivity showed no material associations with such risks.

CONCLUSIONS

Genetic alcohol sensitivity, especially that with the genotype combination of ALDH2(*)1/(*)1 and ADH1B(*)1/(*)1, was significantly associated with an increased risk of depressive and anxiety disorders as well as ARD.

Genetic alcohol sensitivity regulated by ALDH2 and ADH1B polymorphisms as indicator of mental disorders in Japanese employees

AIMS

Alcohol-related disorders (ARD) have been shown to be accompanied by a variety of other comorbid mental disorders. This study evaluated the associations between a variety of mental disorders and genetic alcohol sensitivity.

METHODS

A total of 1944 Japanese workers were interviewed regarding their mental disorders by the Mini-International Neuropsychiatric Interview (M.I.N.I.). We investigated the relationship of ADH1B rs1229984 and ALDH2 rs671 polymorphisms' combination with mental disorder risks. Logistic regression analysis was used to evaluate the associations between those polymorphisms and mental disorders, adjusting for sex, age, and job rank.

RESULTS

The degree of alcohol sensitivity was classified into five groups according to the combination of ADH1B and ALDH2 genotypes (Group I-V in order starting from the lowest alcohol sensitivity). Those with ALDH2 *1/*1 and ADH1B *1/*1 or with ALDH2 *1/*1 and ADH1B *1/*2,*2/*2 (low sensitivity) were significantly or nearly significantly associated with an increased risk of ARD compared with those with ALDH2 *1/*2 and ADH1B *1/*2,*2/*2 as a reference. Those with ALDH2 *1/*1 and ADH1B *1/*1 were also likely to be at an increased risk of any mental disorder except ARD, as well as disorders without comorbid ARD. This tendency was more apparent among women (OR 11.94, 95% CI 0.73-195.63) and non-drinkers (OR 5.43, 95% CI 1.05-28.23).

CONCLUSION

The genotype combination of ALDH2 *1/*1 and ADH1B *1/*1 is significantly associated with an increased risk of any mental disorder, especially ARD. Non-drinkers or women with ALDH2 *1/*1 and ADH1B *1/*1 are likely to suffer from any mental disorder except ARD.

Roles of the ALDH2 and ADH1B genotypes on the association between alcohol intake and serum adiponectin levels among Japanese male workers

BACKGROUND

Adiponectin secreted from adipose tissue is assumed to mediate protective effects on development of metabolic syndrome (MetS) and MetS-related diseases such as cardiovascular diseases and cancer. Relationship between alcohol intake and circulating adiponectin levels is not consistent among the several previous studies. In the present study, we investigated effects of alcohol intake and the alcohol-related polymorphisms on serum adiponectin levels among Japanese male workers.

METHODS

We conducted a cross-sectional design study with 541 male workers aged 51.5 ± 5.9 (mean ± SD) years in a Japanese plant. Information on alcohol intake and other lifestyles was obtained by a self-administered questionnaire. Serum total adiponectin (T-Ad), high-molecular-weight adiponectin (HMW-Ad), medium-molecular-weight adiponectin (MMW-Ad), and low-molecular-weight adiponectin (LMW-Ad) levels were measured by the enzyme-linked immune assay system kit. Two genotypes in the alcohol dehydrogenase-1B (ADH1B) and aldehyde dehydrogenase-2 (ALDH2) genes were determined using blood sample. In multivariate regression analyses, we adjusted for age, body mass index, smoking, and physical exercise.

RESULTS

Among all subjects, high alcohol consumption of 12 units (1 unit contains 22.9 g of ethanol) a week or more was negatively associated with T-Ad levels in the multivariate model, although not significant. When we performed analyses separately for each genotype, high alcohol consumption was negatively associated with T-Ad, HMW-Ad, and LMW-Ad levels only in those with ADH1B *2/*2. Such relationships were not observed in each ALDH2 genotype group.

CONCLUSIONS

High alcohol consumption was inversely associated with T-Ad, HMW-Ad, and LMW-Ad levels in those with ADH1B *2/*2 genotype, but not in those with the other ADH1B genotypes. To our knowledge, this is the first study that reports combined effects of the alcohol-related polymorphisms and alcohol intake on serum adiponectin levels. Additional studies are required to confirm the present finding.

Trends in gastrectomy and ADH1B and ALDH2 genotypes in Japanese alcoholic men and their gene-gastrectomy, gene-gene and gene-age interactions for risk of alcoholism

AIMS

The life-time drinking profiles of Japanese alcoholics have shown that gastrectomy increases susceptibility to alcoholism. We investigated the trends in gastrectomy and alcohol dehydrogenase-1B (ADH1B) and aldehyde dehydrogenase-2 (ALDH2) genotypes and their interactions in alcoholics.

METHODS

This survey was conducted on 4879 Japanese alcoholic men 40 years of age or older who underwent routine gastrointestinal endoscopic screening during the period 1996-2010. ADH1B/ALDH2 genotyping was performed in 3702 patients.

RESULTS

A history of gastrectomy was found in 508 (10.4%) patients. The reason for the gastrectomy was peptic ulcer in 317 patients and gastric cancer in 187 patients. The frequency of gastrectomy had gradually decreased from 13.3% in 1996-2000 to 10.5% in 2001-2005 and to 7.8% in 2006-2010 (P < 0.0001). ADH1B*1/*1 was less frequent in the gastrectomy group than in the non-gastrectomy group (age-adjusted prevalence: 20.4 vs. 27.6%, P = 0.006). ALDH2 genotype distribution did not differ between the two groups. The frequency of inactive ALDH2*1/*2 heterozygotes increased slightly from 13.0% in 1996-2000 to 14.0% in 2001-2005 and to 15.4% in 2006-2010 (P < 0.08). Two alcoholism-susceptibility genotypes, ADH1B*1/*1 and ALDH2*1/*1, modestly but significantly tended not to occur in the same individual (P = 0.026). The frequency of ADH1B*1/*1 decreased with ascending age groups.

CONCLUSIONS

The high frequency of history of gastrectomy suggested that gastrectomy is still a risk factor for alcoholism, although the percentage decreased during the period. The alcoholism-susceptibility genotype ADH1B*1/*1 was less frequent in the gastrectomy group, suggesting a competitive gene-gastrectomy interaction for alcoholism. A gene-gene interaction and gene-age interactions regarding the ADH1B genotype were observed.

Combination of ADH1B*2/ALDH2*2 polymorphisms alters acetaldehyde-derived DNA damage in the blood of Japanese alcoholics

The acetaldehyde associated with alcoholic beverages is an evident carcinogen for the esophagus. Genetic polymorphisms of the alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2) genes are associated with the risk of esophageal cancer. However, the exact mechanism via which these genetic polymorphisms affect esophageal carcinogenesis has not been elucidated. ADH1B*2 is involved in overproduction of acetaldehyde due to increased ethanol metabolism into acetaldehyde, and ALDH2*2 is involved in accumulation of acetaldehyde due to the deficiency of acetaldehyde metabolism. Acetaldehyde can interact with DNA and form DNA adducts, resulting in DNA damage. N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) is the most abundant DNA adduct derived from acetaldehyde. Therefore, we quantified N(2)-ethylidene-dG levels in blood samples from 66 Japanese alcoholic patients using liquid chromatography/electrospray tandem mass spectrometry, and investigated the relationship between N(2)-ethylidene-dG levels and ADH1B and ALDH2 genotypes. The median N(2)-ethylidene-dG levels (25th percentile, 75th percentile) in patients with ADH1B*1/*1 plus ALDH2*1/*1, ADH1B*2 carrier plus ALDH2*1/*1, ADH1B*1/*1 plus ALDH2*1/*2, and ADH1B*2 carrier plus ALDH2*1/*2 were 2.14 (0.97, 2.37)/10(7) bases, 2.38 (1.18, 2.98)/10(7) bases, 5.38 (3.19, 6.52)/10(7) bases, and 21.04 (12.75, 34.80)/10(7) bases, respectively. In the ALDH2*1/*2 group, N(2)-ethylidene-dG levels were significantly higher in ADH1B*2 carriers than in the ADH1B*1/*1 group (P < 0.01). N(2)-ethylidene-dG levels were significantly higher in the ALDH2*1/*2 group than in the ALDH2*1/*1 group, regardless of ADH1B genotype (ADH1B*1/*1, P < 0.05; ADH1B*2 carriers, P < 0.01) N(2)-ethylidene-dG levels in blood DNA of the alcoholics was remarkably higher in individuals with a combination of the ADH1B*2 and ALDH2*2 alleles. These results provide a new perspective on the carcinogenicity of the acetaldehyde associated with alcoholic beverages, from the aspect of DNA damage.

The role of ALDH2 and ADH1B polymorphism in alcohol consumption and stroke in Han Chinese

The genes encoding the enzymes for metabolising alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2) -- exhibit genetic polymorphism and ethnic variations. Although the ALDH2*2 variant allele has been widely accepted as protecting against the development of alcoholism in Asians, the association of the ADH1B*2 variant allele with drinking behaviour remains inconclusive. The goal of this study was to determine whether the polymorphic ADH1B and ALDH2 genes are associated with stroke in male Han Chinese with high alcohol consumption. Sixty-five stroke patients with a history of heavy drinking (HDS) and 83 stroke patients without such a history (NHDS) were recruited for analysis of the ADH1B and ALDH2 genotypes from the stroke registry in the Tri-Service General Hospital, Taipei, Taiwan, between January 2000 and December 2001. The allelotypes of ADH1B and ALDH2 were determined using the polymerase chain reaction-restriction fragment length polymorphism method. The HDS patients (3 per cent) showed a significantly lower ALDH2*2 allele frequency than NHDS patients (27 per cent) (p < 0.001). After controlling for age, patients with HDS were associated with a significantly higher occurrence of cigarette smoking (p < 0.01) and liver dysfunction (p < 0.01). Multiple logistic regression analyses revealed that the ALDH2*2 variant allele was an independent variable exhibiting strong protection (odds ratio 0.072; 95 per cent confidence interval 0.02-0.26) against HDS after adjustment for hypertension, diabetes mellitus, smoking status and liver dysfunction. By contrast, allelic variations in ADH1B exerted no significant effect on HDS. The present study indicated that, unlike ALDH2*2, ADH1B*2 appears not to be a significant negative risk factor for high alcohol consumption in male Han Chinese with stroke.

p53 protein accumulation, iodine-unstained lesions, and alcohol dehydrogenase-1B and aldehyde dehydrogenase-2 genotypes in Japanese alcoholic men with esophageal dysplasia

Inactive heterozygous aldehyde dehydrogenase-2 (ALDH2(*)1/(*)2) and less-active alcohol dehydrogenase-1B (ADH1B(*)1/(*)1) increase the risk of esophageal cancer in East Asian drinkers, and esophageal cancer multiplicity is strongly associated with ALDH2(*)1/(*)2. p53 alterations are key molecular events in multifocal carcinogenesis in the esophagus. We studied 260 esophageal-cancer free Japanese alcoholics with esophageal dysplasia diagnosed by biopsy of distinct iodine-unstained lesions (DIULs) ≥5mm. The degree of p53 protein accumulation was positively associated with the degree of atypia (p<0.0001) and size (p=0.040) of DIULs and with the presence of multiple DIULs (p=0.070), but not with ALDH2(*)1/(*)2 or ADH1B(*)1/(*)1.

Alcohol and aldehyde dehydrogenase polymorphisms and a new strategy for prevention and screening for cancer in the upper aerodigestive tract in East Asians

The ethanol in alcoholic beverages and the acetaldehyde associated with alcohol consumption are Group 1 human carcinogens (WHO, International Agency for Research on Cancer). The combination of alcohol consumption, tobacco smoking, the inactive heterozygous aldehyde dehydrogenase-2 genotype (ALDH2*1/*2) and the less-active homozygous alcohol dehydrogenase-1B genotype (ADH1B*1/*1) increases the risk of squamous cell carcinoma (SCC) in the upper aerodigestive tract (UADT) in a multiplicative fashion in East Asians. In addition to being exposed to locally high levels of ethanol, the UADT is exposed to a very high concentration of acetaldehyde from a variety of sources, including that as an ingredient of alcoholic beverages per se and that found in tobacco smoke; acetaldehyde is also produced by salivary microorganisms and mucosal enzymes and is present as blood acetaldehyde. The inefficient degradation of acetaldehyde by weakly expressed ALDH2 in the UADT may be cri! tical to the local accumulation of acetaldehyde, especially in ALDH2*1/*2 carriers. ADH1B*1/*1 carriers tend to experience less intense alcohol flushing and are highly susceptible to heavy drinking and alcoholism. Heavy drinking by persons with the less-active ADH1B*1/*1 leads to longer exposure of the UADT to salivary ethanol and acetaldehyde. The ALDH2*1/*2 genotype is a very strong predictor of synchronous and metachronous multiple SCCs in the UADT. High red cell mean corpuscular volume (MCV), esophageal dysplasia, and melanosis in the UADT, all of which are frequently found in ALDH2*1/*2 drinkers, are useful for identifying high-risk individuals. We invented a simple flushing questionnaire that enables prediction of the ALDH2 phenotype. New health appraisal models that include ALDH2 genotype, the simple flushing questionnaire, or MCV are powerful tools for devising a new strategy for prevention and screening for UADT cancer in East Asians.

Alcohol drinking and esophageal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population

Although alcohol drinking is considered as an important risk factor for esophageal cancer, the magnitude of the association might be varied among geographic areas. Therefore, we reviewed epidemiologic studies on the association between alcohol drinking and esophageal cancer among the Japanese population. Original data were obtained from MEDLINE, searched using PubMed or from searches of the Ichushi database, complemented with manual searches. Evaluation of associations was based on the strength of evidence ('convincing', 'probable', 'possible' or 'insufficient') and the magnitude of association ('strong', 'moderate', 'weak' or 'no association'), together with biological plausibility as previously evaluated by the International Agency of Research on Cancer. We identified four cohort studies and nine case-control studies. All cohort studies and case-control studies showed strong positive associations between esophageal cancer and alcohol drinking. All cohort studies and six case-control studies showed that alcohol drinking had the dose- or frequency-response relationships with esophageal cancer. In addition, four case-control studies showed that acetaldehyde dehydrogenase Glu504Lys polymorphism had strong effect modification with alcohol drinking. We conclude that there is convincing evidence that alcohol drinking increases the risk of esophageal cancer in the Japanese population.

ALDH2 and ADH1B interactions in retrospective reports of low-dose reactions and initial sensitivity to alcohol in Asian American college students

BACKGROUND

A mechanistic model has been proposed for how alcohol-metabolizing gene variants protect individuals from the development of alcohol use disorders, with heightened sensitivity to alcohol being an early step (endophenotype) in this model. This study was designed to determine whether possession of 2 alcohol-metabolizing genes variations, the aldehyde dehydrogenase ALDH2*2 allele and the alcohol dehydrogenase ADH1B*2 allele, was associated with self-reported sensitivity to alcohol at low doses and at initial use.

METHODS

Asian-American college students (N=784) of Chinese and Korean descent were genotyped at the ALDH2 and ADH1B loci and assessed for lifetime alcohol symptoms following 1 or 2 drinks and level of response to alcohol during the first 5 lifetime drinking episodes.

RESULTS

Participants who had an ALDH2*2 allele were more likely to report experiencing all 6 low-dose symptoms and having heightened initial response to alcohol. An interaction was found between ALDH2*2 and ADH1B*2, with ADH1B*2 being associated with heightened self-reported sensitivity to alcohol only in individuals who also possessed 1 ALDH2*2 allele.

CONCLUSIONS

These findings suggest the effects of ADH1B*2 may be felt more strongly in Asians who already have some heightened sensitivity to alcohol from possessing 1 ALDH2*2 allele, but who are not too sensitized to alcohol from possessing 2 ALDH2*2 alleles. These results offer additional insight into the discrepant findings that have been reported in the literature for the role of ADH1B*2 in response to alcohol and the development of alcohol-related problems.

Comparison between self-reported facial flushing after alcohol consumption and ALDH2 Glu504Lys polymorphism for risk of upper aerodigestive tract cancer in a Japanese population

Some Japanese exhibit facial flushing after drinking alcohol. Facial flushing was considered to be caused by acetaldehydemia. The concentration of blood acetaldehyde was concerned with the catalytic activity of acetaldehyde dehydrogenase (ALDH). Acetaldehyde dehydrogenase (ALDH)-2 polymorphism (rs671, Glu504Lys) was known to be associated with upper aerodigestive tract (UAT) cancer due to modulation of ALDH2 enzyme activity. It remains controversial whether facial flushing is useful in predicting UAT cancer risk as a surrogate marker of ALDH2 polymorphism. We conducted a case-control study to assess the risk of UAT cancer and facial flushing and ALDH2 polymorphism. Cases and controls were 585 UAT cancer patients and matched 1170 noncancer outpatients of Aichi Cancer Center Hospital. Information on facial flushing and other lifestyle factors was collected via a self-administered questionnaire. Association between facial flushing, polymorphism, and UAT cancer was assessed by odds ratios and 95% confidence intervals by using conditional logistic regression models. The facial flushing had no significant association with UAT cancer, although ALDH2 Lys allele was significantly associated with UAT cancer. No significant interaction between facial flushing and alcohol consumption was observed in this study, whereas ALDH2 Lys allele had significant association with UAT cancer. The misclassification between facial flushing and ALDH2 genotype was observed in 18% of controls with ALDH2 Glu/Glu genotype and in 16% of controls with ALDH2 Glu/Lys genotype. Facial flushing was less useful to predict UAT cancer risk than genotyping ALDH2 polymorphism.

Associations between ADH gene variants and alcohol phenotypes in Dutch adults

Recently, Macgregor et al. (2009) demonstrated significant associations of ADH polymorphisms with reactions to alcohol and alcohol consumption measures in an Australian sample. The aim of the present study was to replicate these findings in a Dutch sample. Survey data on alcohol phenotypes came from 1,754 unrelated individuals registered with the Netherlands Twin Register. SNPs in the ADH gene cluster located on chromosome 4q (n = 491) were subdivided in seven gene sets: ADH5, ADH4, ADH6, ADH1A, ADH1B, ADH1C and ADH7. Within these sets associations of SNPs with alcohol consumption measures, age at onset variables, reactions to alcohol and problem drinking liability were examined. Of the original 38 SNPs studied by Macgregor et al. (2009), six SNPs were not available in our dataset, because one of them had a minor allele frequency < .01 (rs1229984) and five could not be imputed. The remaining SNP associations with alcohol phenotypes as identified by Macgregor et al. (2009) were not replicated in the Dutch sample, after correcting for multiple genotype and phenotype testing. Significant associations were found however, for reactions to alcohol with a SNP in ADH5 (rs6827292, p = .001) and a SNP just upstream of ADH5 (rs6819724, p = .0007) that is in strong LD with rs6827292. Furthermore, an association between age at onset of regular alcohol use and a SNP just upstream of ADH7 (rs2654849, p = .003) was observed. No significant associations were found for alcohol consumption and problem drinking liability. Although these findings do not replicate the earlier findings at the SNP level, the results confirm the role of the ADH gene cluster in alcohol phenotypes.

Alcohol drinking habits, alcohol dehydrogenase genotypes and risk of acute coronary syndrome

Aims: The risk of myocardial infarction is lower among light-to-moderate drinkers compared with abstainers. Results from some previous studies, but not all, suggest that this association is modified by variations in genes coding for alcohol dehydrogenase (ADH). We aimed to test this hypothesis, including alcohol as both the amount of alcohol and the frequency of drinking. Methods: we conducted a nested case-cohort study within the Danish Diet, Cancer and Health study, including 1,645 men (770 incident cases of acute coronary syndrome from 1993—1997 through 2004 and 875 randomly selected controls). Results: Higher alcohol intake (measured as amount or drinking frequency) was associated with lower risk of acute coronary syndrome; however, there was no evidence that these finding were modified by ADH1B or ADH1C genotypes. Conclusions: The importance of functional variation in alcohol dehydrogenase for the association between alcohol drinking habits and the risk of developing acute coronary syndrome, if any, is very limited.

Polymorphisms of alcohol dehydrogenase-1B and aldehyde dehydrogenase-2 and the blood and salivary ethanol and acetaldehyde concentrations of Japanese alcoholic men

BACKGROUND

The effects of genetic polymorphism of aldehyde dehydrogenase-2 (ALDH2) on alcohol metabolism are striking in nonalcoholics, and the effects of genetic polymorphism of alcohol dehydrogenase-1B (ADH1B) are modest at most, whereas genetic polymorphisms of both strongly affect the susceptibility to alcoholism and upper aerodigestive tract (UADT) cancer of drinkers.

METHODS

We evaluated associations between ADH1B/ADH1C/ALDH2 genotypes and the blood and salivary ethanol and acetaldehyde levels of 168 Japanese alcoholic men who came to our hospital for the first time in the morning and had been drinking until the day before.

RESULTS

The ethanol levels in their blood and saliva were similar, but the acetaldehyde levels in their saliva were much higher than in their blood, probably because of acetaldehyde production by oral bacteria. Blood and salivary ethanol and acetaldehyde levels were both significantly higher in the subjects with the less active ADH1B*1/*1 genotype than in the ADH1B*2 carriers, but none of the levels differed according to ALDH2 genotype. Significant linkage disequilibrium was detected between the ADH1B and ADH1C genotypes, but ADH1C genotype did not affect the blood or salivary ethanol or acetaldehyde levels. High blood acetaldehyde levels were found even in the active ALDH2*1/*1 alcoholics, which were comparable with the levels of the inactive heterozygous ALDH2*1/*2 alcoholics with less active ADH1B*1/*1. The slope of the increase in blood acetaldehyde level as the blood ethanol level increased was significantly steeper in alcoholics with inactive heterozygous ALDH2*1/*2 plus ADH1B*2 allele than with any other genotype combinations, but the slopes of the increase in salivary acetaldehyde level as the salivary ethanol level increased did not differ between the groups of subjects with any combinations of ALDH2 and ADH1B genotypes.

CONCLUSIONS

The ADH1B/ALDH2 genotype affected the blood and salivary ethanol and acetaldehyde levels of nonabstinent alcoholics in a different manner from nonalcoholics, and clear effects of ADH1B genotype and less clear effects of ALDH2 were observed in the alcoholics. Alterations in alcohol metabolism as a result of alcoholism may modify the gene effects, and these findings provide some clues in regard to associations between the genotypes and the risks of alcoholism and UADT cancer.

From nature versus nurture, via nature and nurture, to gene x environment interaction in mental disorders

It is now generally accepted that complex mental disorders are the results of interplay between genetic and environmental factors. This holds out the prospect that by studying G x E interplay we can explain individual variation in vulnerability and resilience to environmental hazards in the development of mental disorders. Furthermore studying G x E findings may give insights in neurobiological mechanisms of psychiatric disorder and so improve individualized treatment and potentially prevention. In this paper, we provide an overview of the state of field with regard to G x E in mental disorders. Strategies for G x E research are introduced. G x E findings from selected mental disorders with onset in childhood or adolescence are reviewed [such as depressive disorders, attention-deficit/hyperactivity disorder (ADHD), obesity, schizophrenia and substance use disorders]. Early seminal studies provided evidence for G x E in the pathogenesis of depression implicating 5-HTTLPR, and conduct problems implicating MAOA. Since then G x E effects have been seen across a wide range of mental disorders (e.g., ADHD, anxiety, schizophrenia, substance abuse disorder) implicating a wide range of measured genes and measured environments (e.g., pre-, peri- and postnatal influences of both a physical and a social nature). To date few of these G x E effects have been sufficiently replicated. Indeed meta-analyses have raised doubts about the robustness of even the most well studied findings. In future we need larger, sufficiently powered studies that include a detailed and sophisticated characterization of both phenotype and the environmental risk.

Functional variants in ADH1B and ALDH2 coupled with alcohol and smoking synergistically enhance esophageal cancer risk

BACKGROUND & AIMS

Esophageal squamous cell carcinoma (ESCC) is prevalent among Asian populations, with marked regional variations in incidence and mortality. Patients with ESCC have a very poor prognosis, but detection of ESCC at earlier stages could improve clinical outcome. Therefore, identification of epidemiologic factors that influence the development of ESCC would facilitate prevention and/or early detection of the disease.

METHODS

We performed a 2-step genome-wide association study with subsequent replication analysis using a total of 1070 Japanese ESCC cases and 2836 controls. We also used logistic regression analysis to estimate the effect of gene-gene and gene-environmental interactions.

RESULTS

We identified the significant associations of ESCC with 4q21-23 and 12q24 regions, which include nonsynonymous single nucleotide polymorphisms (SNP) in ADH1B (rs1229984, P = 6.76 x 10(-35)) and ALDH2 (rs671, P = 3.68 x 10(-68)) that were previously shown to be associated with ESCC susceptibility. Multiple logistic regression analysis revealed SNP rs671, rs1229984, alcohol drinking, and smoking as the independent risk factors for ESCC (odds ratios of 1.66, 1.85, 1.92, and 1.79, respectively). Moreover, individuals who had both genetic and lifestyle-related risk factors had a nearly 190 times higher risk of ESCC than those who had neither of these.

CONCLUSIONS

We found 2 known functional variants involved in the metabolism of alcohol and tobacco by-products as the most significant risk factors for the development of ESCC in a Japanese population. The individuals carrying both risk genotypes have a higher baseline risk of ESCC that is substantially increased by 2 lifestyle risk factors.

Alcohol Intake, Myocardial Infarction, Biochemical Risk Factors, and Alcohol Dehydrogenase Genotypes

Background— The risk of myocardial infarction is lower among light-to-moderate alcohol drinkers compared with abstainers. We tested associations between alcohol intake and risk of myocardial infarction and risk factors and whether these associations are modified by variations in alcohol dehydrogenases.

Methods and Results— We used information on 9584 men and women from the Danish general population in the Copenhagen City Heart Study. During follow-up, from 1991 to 2007, 663 incident cases of myocardial infarction occurred. We observed that increasing alcohol intake was associated with decreasing risk of myocardial infarction, decreasing low-density lipoprotein cholesterol and fibrinogen, increasing diastolic and systolic blood pressure and high-density lipoprotein cholesterol, and with U-shaped nonfasting triglycerides. In contrast, ADH1B and ADH1C genotypes were not associated with risk of myocardial infarction or with any of the cardiovascular biochemical risk factors, and there was no indication that associations between alcohol intake and myocardial infarction and between alcohol intake and risk factors were modified by genotypes.

Conclusions— Increasing alcohol intake is associated with decreasing risk of myocardial infarction, decreasing low-density lipoprotein cholesterol and fibrinogen, increasing diastolic and systolic blood pressure and high-density lipoprotein cholesterol, and U-shaped nonfasting triglycerides. These associations were not modified by ADH1B and ADH1C are genotypes.

Associations of ALDH2 and ADH1B genotypes with alcohol-related phenotypes in Asian young adults

BACKGROUND

Associations of ALDH2 and ADH1B genotypes with alcohol use have been evaluated largely using case-control studies, which typically focus on adult samples and dichotomous diagnostic outcomes. Relatively fewer studies have evaluated ALDH2 and ADH1B in relation to continuous drinking outcomes or at different developmental stages. This study examined additive and interactive effects of ALDH2 and ADH1B genotypes on drinking behavior in a mixed-gender sample of Asian young adults, focusing on continuous phenotypes (e.g., heavy episodic and hazardous drinking, alcohol sensitivity, drinking consequences) whose expression is expected to precede the onset of alcohol use disorders.

METHODS

The sample included 182 Chinese- and Korean-American young adults ages 18 years and older (mean age = 20 years). Effects of ALDH2, ADH1B and ethnicity were estimated using generalized linear modeling.

RESULTS

The ALDH2*2 allele predicted lower reported rates of alcohol use and drinking consequences as well as greater reported sensitivity to alcohol. There were significant ethnic group differences in drinking outcomes, such that Korean ethnicity predicted higher drinking rates and lower alcohol sensitivity. ADH1B status was not significantly related to drinking outcomes.

CONCLUSIONS

Ethnicity and ALDH2 status, but not ADH1B status, consistently explained significant variance in alcohol consumption in this relatively young sample. Results extend previous work by showing an association of ALDH2 genotype with drinking consequences. Findings are discussed in the context of possible developmental and population differences in the influence of ALDH2 and ADH1B variations on alcohol-related phenotypes.

Associations of ADH and ALDH2 gene variation with self report alcohol reactions, consumption and dependence: an integrated analysis

Alcohol dependence (AD) is a complex disorder with environmental and genetic origins. The role of two genetic variants in ALDH2 and ADH1B in AD risk has been extensively investigated. This study tested for associations between nine polymorphisms in ALDH2 and 41 in the seven ADH genes, and alcohol-related flushing, alcohol use and dependence symptom scores in 4597 Australian twins. The vast majority (4296) had consumed alcohol in the previous year, with 547 meeting DSM-IIIR criteria for AD. There were study-wide significant associations (P<2.3 x 10(-4)) between ADH1B-Arg48His (rs1229984) and flushing and consumption, but only nominally significant associations (P<0.01) with dependence. Individuals carrying the rs1229984 G-allele (48Arg) reported a lower prevalence of flushing after alcohol (P=8.2 x 10(-7)), consumed alcohol on more occasions (P=2.7 x 10(-6)), had a higher maximum number of alcoholic drinks in a single day (P=2.7 x 10(-6)) and a higher overall alcohol consumption (P=8.9 x 10(-8)) in the previous year than those with the less common A-allele (48His). After controlling for rs1229984, an independent association was observed between rs1042026 (ADH1B) and alcohol intake (P=4.7 x 10(-5)) and suggestive associations (P<0.001) between alcohol consumption phenotypes and rs1693482 (ADH1C), rs1230165 (ADH5) and rs3762894 (ADH4). ALDH2 variation was not associated with flushing or alcohol consumption, but was weakly associated with AD measures. These results bridge the gap between DNA sequence variation and alcohol-related behavior, confirming that the ADH1B-Arg48His polymorphism affects both alcohol-related flushing in Europeans and alcohol intake. The absence of study-wide significant effects on AD results from the low P-value required when testing multiple single nucleotide polymorphisms and phenotypes.

Alcoholism and alcohol drinking habits predicted from alcohol dehydrogenase genes

Alcohol drinking habits and alcoholism are partly genetically determined. Alcohol is degraded primarily by alcohol dehydrogenase (ADH) wherein genetic variation that affects the rate of alcohol degradation is found in ADH1B and ADH1C. It is biologically plausible that these variations may be associated with alcohol drinking habits and alcoholism. By genotyping 9080 white men and women from the general population, we found that men and women with ADH1B slow vs fast alcohol degradation drank more alcohol and had a higher risk of everyday drinking, heavy drinking, excessive drinking and of alcoholism. For example, the weekly alcohol intake was 9.8 drinks (95% confidence interval (CI): 9.1-11) among men with the ADH1B.1/1 genotype compared to 7.5 drinks (95% CI: 6.4-8.7) among men with the ADH1B.1/2 genotype, and the odds ratio (OR) for heavy drinking was 3.1 (95% CI: 1.7-5.7) among men with the ADH1B.1/1 genotype compared to men with the ADH1B.1/2 genotype. Furthermore, individuals with ADH1C slow vs fast alcohol degradation had a higher risk of heavy and excessive drinking. For example, the OR for heavy drinking was 1.4 (95% CI: 1.1-1.8) among men with the ADH1C.1/2 genotype and 1.4 (95% CI: 1.0-1.9) among men with the ADH1B.2/2 genotype, compared with men with the ADH1C.1/1 genotype. Results for ADH1B and ADH1C genotypes among men and women were similar. Finally, because slow ADH1B alcohol degradation is found in more than 90% of the white population compared to less than 10% of East Asians, the population attributable risk of heavy drinking and alcoholism by ADH1B.1/1 genotype was 67 and 62% among the white population compared with 9 and 24% among the East Asian population.

Alcohol dehydrogenase 1B genotype and fetal alcohol syndrome: a HuGE minireview

Fetal alcohol syndrome (FAS), 1 of the most common developmental disabilities in the United States, occurs at a rate of 0.5-2.0:1000 live births. Animal model, family, and twin studies suggest a genetic component to FAS susceptibility. Alcohol dehydrogenases (ADHs) catalyze the rate-limiting step in alcohol metabolism. Studies of genetic associations with FAS have focused on the alcohol dehydrogenase 1B (ADH1B) gene, comparing mothers and children with the alleles ADH1B*2 or ADH1B*3, associated with faster ethanol metabolism, with those homozygous for ADH1B*1. While most studies have found a protective effect for genotypes containing ADH1B*2 or ADH1B*3, results have been conflicting, and further investigation into the association between the ADH1B genotype and FAS is needed. Whether increased alcohol intake accounts for the elevated risk reported for the ADH1B*1/ADH1B*1 genotype should be addressed, and future studies would benefit from consistent case definitions, enhanced exposure measurements, larger sample sizes, and careful study design.

Association of gene polymorphisms with intervertebral disc degeneration and vertebral osteophyte formation

STUDY DESIGN

Cross-sectional cohort study of elderly people.

OBJECTIVES

To examine the factors influencing osteophyte formation without lumbar disc degeneration and to estimate the implications of osteophytes from the viewpoint of low back pain and gene polymorphisms.

SUMMARY OF BACKGROUND DATA

The degenerative changes that occur in the intervertebral discs are the point of departure of osteophyte formation. Several studies on factors associated with genetic susceptibility to spinal osteophyte formation, such as VDR and TGF-beta1. However, there are no detailed studies concerning osteophytes not accompanied with disc degeneration.

METHODS

A total of 387 elderly persons were recruited, and disc degeneration and osteophyte formation were evaluated. The cases with osteophyte formation were classified into 3 groups: osteophyte formation with disc height narrowing (n = 217), osteophyte formation without disc height narrowing (n = 99), and control group defined as the cases without osteophyte formation (n = 71). Twelve genotypes were characterized. Correlations between these degenerative factors and the polymorphisms were analyzed.

RESULTS

The prevalence of low back pain was significantly greater in the group of osteophyte formation with disc height narrowing than the other 2 groups. In the polymorphism of alcohol dehydrogenase (ADH2), prevalence of osteophyte formation without disc height narrowing was less in His/Arg (odds ratio = 0.57, P = 0.041) and Arg/Arg (odds ratio = 0.41, P = 0.18) than His/His.

CONCLUSIONS

Patients with osteophyte formation preceding intervertebral disc narrowing had a lower risk of low back pain compared with those without osteophytes. The 47Arg polymorphism in the ADH2 may act to suppress osteophyte formation unaffected by disc degeneration.

Contribution of the alcohol dehydrogenase-1B genotype and oral microorganisms to high salivary acetaldehyde concentrations in Japanese alcoholic men

The less-active homozygous alcohol dehydrogenase-1B (ADH1B*1/*1) and inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/*2) increase the risk of upper aerodigestive tract cancer (UADTC) in Japanese alcoholics. We evaluated associations between ADH1B/ALDH2 genotypes and the blood and salivary ethanol/acetaldehyde levels of 80 Japanese alcoholic men in the morning when they first visited our hospital after drinking the day before. Higher levels of ethanol persisted in the blood for longer periods in ADH1B*1/*1 carriers (n = 25) than in ADH1B*2 allele carriers after adjustment for the amount and time of the preceding alcohol consumption and body weight [median (25th-75th %): 20.5 mM (15.5-52.4) vs. below detection level (<DL) (<DL-6.4), p = 0.0003]. The ethanol levels in blood and saliva were similar, but the acetaldehyde levels in saliva were strikingly higher than in the blood, and were higher in ADH1B*1/*1 carriers than in ADH1B*2 allele carriers [47.4 muM (22.2-87.6) vs. 1.60 (<DL-26.3) in the saliva, p = 0.009]. The salivary acetaldehyde levels were correlated with salivary acetaldehyde production (r = 0.34, p = 0.002). The oral bacteria and yeast counts were correlated with salivary acetaldehyde production. Both the microorganisms counts and acetaldehyde production decreased after 3 weeks of abstinence, and the decreases were correlated (r = 0.35, p = 0.042). No effect of inactive ALDH2 (n = 12) on ethanol lingering the next morning was observed. In conclusion, the high salivary acetaldehyde levels in the alcoholics were partly attributable to prolonged ethanol exposure because of the less-active ADH1B and increased salivary acetaldehyde production as a result of oral microorganism overgrowth, and may explain their high risk for UADTC.

INFLUENCE OF DRINKING ALCOHOL ON ATHEROSCLEROTIC RISK IN ALCOHOL FLUSHERS AND NON-FLUSHERS OF ORIENTAL PATIENTS WITH TYPE 2 DIABETES MELLITUS

AIMS

Facial flushing caused by alcohol drinking is a typical symptom of high sensitivity to alcohol in orientals. We investigated whether drinking alcohol influences atherosclerotic risk factors in alcohol flushers and non-flushers in patients with diabetes mellitus.

METHODS

A cross-sectional study was performed using 225 subjects with type 2 diabetes. Sensitivity to alcohol was surveyed by a questionnaire on facial flushing. Subjects were divided into three groups by average amount of alcohol drinking (non-drinkers; light drinkers: <140 g/week; heavy drinkers: 140 g/week or more).

RESULTS

Systolic blood pressure and blood HDL cholesterol were significantly higher in heavy drinkers than in non-drinkers. There were no significant differences in body mass index, blood pressure, blood total cholesterol, HDL cholesterol, uric acid, fibrinogen and sialic acid levels in flushers and non-flushers. In alcohol flushers, diastolic blood pressure and HDL cholesterol in heavy drinkers were significantly higher than those in non-drinkers, and systolic blood pressure was significantly higher in heavy drinkers than in non-drinkers and light drinkers. On the other hand, blood pressure and HDL cholesterol in non-flushers were not significantly different among non-, light and heavy drinkers. Serum total cholesterol was not significantly different among the three drinking groups both in flushers and non-flushers.

CONCLUSIONS

Blood pressure and HDL cholesterol are more prone to be affected by drinking in flushers than in non-flushers, suggesting that alcohol sensitivity evaluated by flushing response due to drinking alcohol should be taken into account when the effects of alcohol drinking on atherosclerotic risk factors are considered in oriental patients with type 2 diabetes mellitus.

Application of aldehyde dehydrogenase 2 (ALDH2) Genetic Diagnosis in Support of Decreasing Alcohol Intake

Encouraging behavioral changes to decrease alcohol intake is not easy from the standpoint of health support. This study was conducted to examine whether the genetic diagnosis of ALDH2 polymorphism is useful in supporting those who want to decrease their alcohol intake. The participants in this study were 329 male employees who wanted to know the result of their ALDH2 genotype. We divided the 329 participants randomly into two groups. One was the "notified group" (n=157), and the other was the "non-notified group" (n=172). The subjects belonging to the "notified group" were informed of the results of the ALDH2 genotype diagnosis in April, 2003. Drinking habits and laboratory data were obtained before and after notification of the ALDH2 genotype. Among those with genotype ALDH2*1/*1, there was no significant change in drinking frequencies, nor was there any significant decline in liver function laboratory data in either of the groups before and after notification of the genotype. However, weekly alcohol intake tended to increase compared to that before notification. On the other hand, with regard to those with genotype ALDH2*1/*2, no significant changes in drinking frequencies or liver function laboratory data were evident in either group before and after notification of the genotype. However, the weekly alcohol intake tended to increase in the non-notified group, whereas it tended to decrease in the notified group. Although the result was not significant, it is suggested that, with further study and an increased sample size, the genetic diagnosis may be found to be useful.