Do the ethanol metabolizing enzymes modify the relationship between alcohol consumption and blood pressure?

The ALDH2 gene rs671 polymorphism is associated with cardiometabolic risk factors in East Asian population: an updated meta-analysis

Introduction

Acetaldehyde dehydrogenase 2 (ALDH2) had reported as a prominent role in the development of cardiometabolic diseases among Asians. Our study aims to investigate the relationship between ALDH2 polymorphism and cardiometabolic risk factors in East Asian population.

Method

We searched databases of PubMed, Web of Science, and Embase updated to Oct 30th, 2023. We extracted data of BMI, Hypertension, SBP, DBP, T2DM, FBG, PPG, HbA1c, TG, TC, LDL-C and HDL-C.

Result

In total, 46 studies were finally included in our meta-analysis, containing, 54068 GG and, 36820 GA/AA participants. All outcomes related to blood pressure revealed significant results (hypertension OR=0.83 [0.80, 0.86]; SBP MD=-1.48 [-1.82, -1.14]; DBP MD=-1.09 [-1.58, -0.61]). FBG showed a significant difference (MD=-0.10 [-0.13, -0.07]), and the lipid resulted significantly in some outcomes (TG MD=-0.07 [-0.09, -0.04]; LDL-C MD=-0.04 [-0.05, -0.02]). As for subgroups analysis, we found that in populations without severe cardiac-cerebral vascular diseases (CCVDs), GG demonstrated a significantly higher incidence of T2DM (T2DM OR=0.88 [0.79, 0.97]), while the trend was totally opposite in population with severe CCVDs (T2DM OR=1.29 [1.00, 1.66]) with significant subgroup differences.

Conclusion

Our updated meta-analysis demonstrated that ALDH2 rs671 GG populations had significantly higher levels of BMI, blood pressure, FBG, TG, LDL-C and higher risk of hypertension than GA/AA populations. Besides, to the best of our knowledge, we first report GG had a higher risk of T2DM in population without severe CCVDs, and GA/AA had a higher risk of T2DM in population with severe CCVDs.Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023389242.

Association Between ALDH-2 rs671 and Essential Hypertension Risk or Blood Pressure Levels: A Systematic Review and Meta-Analysis

Background: The association between Aldehyde dehydrogenase II (ALDH-2) rs671 polymorphism and essential hypertension (EH) risk or blood pressure (BP) levels remains unclear. Objective: To systematically review the influence of the aldehyde dehydrogenase II rs671 polymorphism on essential hypertension risk and blood pressure levels. Methods: The PubMed, EMbase, Web of Science, Cochrane Library, CNKI and CBM databases were electronically searched to identify case-control or cohort studies published prior to July 2019 that examined the association between the rs671 polymorphism and the risk of essential hypertension or blood pressure levels. A meta-analysis was conducted with Stata 15.1 software. Results: Twenty-two articles were included. Among these articles, 20 incorporated 30 individual studies evaluating the association between the rs671 polymorphism and EH (11,051 hypertensive patients and 15,926 normotensive controls), and 8 incorporated 12 individual studies evaluating the association between the rs671 polymorphism and BP (20,512 subjects). The results of the meta-analysis showed that the mutation of the rs671 polymorphism was associated with a significantly decreased risk of EH in all models: allelic model (OR = 0.80, 95% CI: 0.73-0.87), homozygous model (OR = 0.71, 95% CI: 0.63-0.80), heterozygous model (OR = 0.79, 95% CI: 0.72-0.87), dominant model (OR = 0.79, 95% CI: 0.71-0.87), and recessive model (OR = 0.76, 95% CI: 0.68-0.85). In the stratified analyses, significant associations were found for males, drinkers and population-based studies. Simultaneously, the A carriers had lower SBP (WMD = -1.78, 95% CI: -3.02 to -0.53) and DBP (WMD = -1.09, 95% CI: -1.58 to -0.61) levels than individuals with the GG homozygote. Conclusion: The collective findings of this meta-analysis suggested that the ALDH-2 rs671 polymorphism represented an important genetic marker in the development of hypertension. Considering the overall quality of evidence and the relatively small pooled sample size, more well-conducted high-quality studies are required to verify the above conclusion. Systematic Review Registration Number: PROSPERO (CRD42019129746).

Effect of alcohol on blood pressure

BACKGROUND

Alcohol is consumed by over 2 billion people worldwide. It is a common substance of abuse and its use can lead to more than 200 disorders including hypertension. Alcohol has both acute and chronic effects on blood pressure. This review aimed to quantify the acute effects of different doses of alcohol over time on blood pressure and heart rate in an adult population.

OBJECTIVES

Primary objective To determine short-term dose-related effects of alcohol versus placebo on systolic blood pressure and diastolic blood pressure in healthy and hypertensive adults over 18 years of age. Secondary objective To determine short-term dose-related effects of alcohol versus placebo on heart rate in healthy and hypertensive adults over 18 years of age.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to March 2019: the Cochrane Hypertension Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 2), in the Cochrane Library; MEDLINE (from 1946); Embase (from 1974); the World Health Organization International Clinical Trials Registry Platform; and ClinicalTrials.gov. We also contacted authors of relevant articles regarding further published and unpublished work. These searches had no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing effects of a single dose of alcohol versus placebo on blood pressure (BP) or heart rate (HR) in adults (≥ 18 years of age).

DATA COLLECTION AND ANALYSIS

Two review authors (ST and CT) independently extracted data and assessed the quality of included studies. We also contacted trial authors for missing or unclear information. Mean difference (MD) from placebo with 95% confidence interval (CI) was the outcome measure, and a fixed-effect model was used to combine effect sizes across studies.  MAIN RESULTS: We included 32 RCTs involving 767 participants. Most of the study participants were male (N = 642) and were healthy. The mean age of participants was 33 years, and mean body weight was 78 kilograms. Low-dose alcohol (< 14 g) within six hours (2 RCTs, N = 28) did not affect BP but did increase HR by 5.1 bpm (95% CI 1.9 to 8.2) (moderate-certainty evidence). Medium-dose alcohol (14 to 28 g) within six hours (10 RCTs, N = 149) decreased systolic blood pressure (SBP) by 5.6 mmHg (95% CI -8.3 to -3.0) and diastolic blood pressure (DBP) by 4.0 mmHg (95% CI -6.0 to -2.0) and increased HR by 4.6 bpm (95% CI 3.1 to 6.1) (moderate-certainty evidence for all).  Medium-dose alcohol within 7 to 12 hours (4 RCTs, N = 54) did not affect BP or HR. Medium-dose alcohol > 13 hours after consumption (4 RCTs, N = 66) did not affect BP or HR. High-dose alcohol (> 30 g) within six hours (16 RCTs, N = 418) decreased SBP by 3.5 mmHg (95% CI -6.0 to -1.0), decreased DBP by 1.9 mmHg (95% CI-3.9 to 0.04), and increased HR by 5.8 bpm (95% CI 4.0 to 7.5). The certainty of evidence was moderate for SBP and HR, and was low for DBP. High-dose alcohol within 7 to 12 hours of consumption (3 RCTs, N = 54) decreased SBP by 3.7 mmHg (95% CI -7.0 to -0.5) and DBP by 1.7 mmHg (95% CI -4.6 to 1.8) and increased HR by 6.2 bpm (95% CI 3.0 to 9.3). The certainty of evidence was moderate for SBP and HR, and low for DBP. High-dose alcohol ≥ 13 hours after consumption (4 RCTs, N = 154) increased SBP by 3.7 mmHg (95% CI 2.3 to 5.1), DBP by 2.4 mmHg (95% CI 0.2 to 4.5), and HR by 2.7 bpm (95% CI 0.8 to 4.6) (moderate-certainty evidence for all).  AUTHORS' CONCLUSIONS: High-dose alcohol has a biphasic effect on BP; it decreases BP up to 12 hours after consumption and increases BP > 13 hours after consumption. High-dose alcohol increases HR at all times up to 24 hours. Findings of this review are relevant mainly to healthy males, as only small numbers of women were included in the included trials.

Associations between aldehyde dehydrogenase 2 (ALDH2) rs671 genetic polymorphisms, lifestyles and hypertension risk in Chinese Han people

Hypertension is a multiple factor disease which was influenced by gene, environment, and lifestyle. Several studies confirmed that the ALDH2 rs671 polymorphism is associated with hypertension. However, the evidence remains inconclusive. Whether lifestyle affects blood pressure in different genotype groups have not been clarified, either. The subjects were adult Chinese Han people who received health examination in the period from December 2014 to December 2015. Detection of the ALDH2 r671 polymorphism was determined by polymerase chain reaction. Lifestyle data were collected using self-administered questionnaires. Basic characteristics and fasting venous blood sample were collected at baseline. 4018 subjects were eligible for participation.The frequencies of the ALDH2 rs671 genotype were 68.67% (GG), 28.67%(GL), 2.66%(LL), respectively. Pepole who harbored the L allele were less likely to develop incident hypertension. There was a significant association between food frequency and hypertension in the L genotype group. Fried food intake was significantly increased the risk of hypertension in the L genotype group. Our study suggested that ALDH2 rs671 L-genotypes are protective factors for hypertension in Han Chinese. Consumption of fried food accelerated the development of hypertension in individuals with poor metabolism of acetaldehyde.

The ALDH2 gene rs671 polymorphism is not associated with essential hypertension

Essential hypertension (EH) is a worldwide problem. Acetaldehyde dehydrogenase 2 (ALDH2) gene has been suggested to be correlated with EH. However, the results are inconsistent. This study aimed to investigate the associations of ALDH2 rs671 polymorphism with EH in a Chinese Han population in Shanghai. Genotype of ALDH2 rs671 was analyzed in 1923 EH patients and 1115 control subjects. We found no association between ALDH2 rs671 and EH risk or EH-related quantitative blood chemistry values. Furthermore, a meta-analysis was performed and the summary results from 11220 patients and 8339 control subjects were consistent with our findings. These results indicated that rs671 of ALDH2 may not associate with the risk of EH.

Positive association between ALDH2 rs671 polymorphism and essential hypertension: A case-control study and meta-analysis

Background and objective

Several studies have been conducted to examine the association between aldehyde dehydrogenase 2 family (ALDH2) rs671 polymorphism and essential hypertension (EH). However, the results remain inconsistent. This study aimed to clarify the association between ALDH2 rs671 polymorphism and EH susceptibility.

Methods

One thousand and ninety-four cases and 1236 controls who were ethnic Han Chinese were collected for this population-based case-control study. A meta-analysis was performed to calculate the pooled odds ratio and 95% confidence interval, using allele contrast, dominant, recessive, and co-dominant models using fixed or random-effect models.

Results

Significant differences were observed between EH cases and controls at the level of both genotype (χ² = 6.656, P<0.05) and alleles (χ² = 6.314, P<0.05). An additional meta-analysis using 4204 cases and 5435 controls established that rs671 was significantly associated with EH (P<0.00001).

Conclusion

The results of our case-control study and meta-analysis showed that there is a significant association between ALDH2 rs671 polymorphism and EH susceptibility. In addition, the results of the breakdown analysis by gender suggest a male-specific association between the ALDH2 rs671 polymorphism and EH.

Does the flushing response modify the relationship between alcohol intake and hypertension in the Japanese population? NIPPON DATA2010

The influence of alcohol intake on hypertension may vary depending on the flushing response, but this relationship has not been confirmed. The relationship between alcohol intake and hypertension was examined according to the flushing response in a representative sample of the Japanese population. Participants in the National Health and Nutrition Survey in 2010 were asked to participate in the baseline survey of NIPPON DATA2010. Here, we investigated the relationship between alcohol intake and hypertension according to the flushing response. Statistical analyses were performed in a cross-sectional manner using multiple logistic regression models after adjusting for age, body mass index, smoking status, present illness of diabetes mellitus and present illness of dyslipidemia. Of the 1139 men and 1263 women, 659 and 463, respectively, had hypertension. Among the men, alcohol intake was positively associated with hypertension, regardless of the flushing response (P for linear trend both <0.05). This positive relationship was observed for both users and non-users of antihypertensive drugs. No interaction with the flushing response was observed (P for interaction=0.360). In women, although the direction differed between flushers and non-flushers, the association between alcohol intake and hypertension was not significant, regardless of flushing response. In conclusion, In Japanese men, alcohol intake was positively associated with hypertension in a manner that was not influenced by the flushing response.

Differential Effect of Initiating Moderate Red Wine Consumption on 24-h Blood Pressure by Alcohol Dehydrogenase Genotypes: Randomized Trial in Type 2 Diabetes

AIMS

Observational studies report inconsistent associations between moderate alcohol intake and blood pressure (BP). In a sub-study of a larger randomized controlled trial, we assessed the effect of initiating moderate red wine consumption on 24-h BP recordings and the effect of a common genetic variant of alcohol dehydrogenases (ADH) among patients with type 2 diabetes.

METHODS

Fifty-four type 2 diabetes, alcohol abstainers were randomized to consume 150 ml/dinner dry red wine or mineral water. Both groups were guided to adhere to a Mediterranean diet, without caloric restriction. We measured 24-h ambulatory BP monitoring (ABPM) at baseline and after 6 months.

RESULTS

Participants (age = 57 years; 85% men; mean 24-h BP = 129/77 mm Hg) had 92% 6-month retention. After 6 months of intervention, the average 24-h BP did not differ between the wine and water groups. A transient decrease in BP was observed in the red wine group at midnight (3-4 hours after wine intake: systolic BP: red wine = -10.6mm Hg vs. mineral water = +2.3 mm Hg; P = 0.031) and the following morning at 7-9 am (red wine: -6.2mm Hg vs. mineral water: +5.6mm Hg; P = 0.014). In a second post hoc sub-analysis among the red wine consumers, individuals who were homozygous for the gene encoding ADH1B*2 variant (Arg48His; rs1229984, TT, fast ethanol metabolizers), exhibited a reduction in mean 24-h systolic BP (-8.0mm Hg vs. +3.7 mm Hg; P = 0.002) and pulse pressure (-3.8 mm Hg vs. +1.2 mm Hg; P = 0.032) compared to heterozygotes and those homozygous for the ADH1B*1 variant (CC, slow metabolizers).

CONCLUSIONS

Initiating moderate red wine consumption at dinner among type 2 diabetes patients does not have a discernable effect on mean 24-h BP. Yet, a modest temporal BP reduction could be documented, and a more pronounced BP-lowering effect is suggested among fast ethanol metabolizers.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov Identifier: NCT00784433.

Effect of alcohol and aldehyde dehydrogenase gene polymorphisms on alcohol-associated hypertension: the Guangzhou Biobank Cohort Study

The effects of alcohol dehydrogenase (ADH) 2 and aldehyde dehydrogenase (ALDH) 2 genotypes on the alcohol–blood pressure association are unclear. We examined the association of ADH2 or ALDH2 genotypes with blood pressure in older Chinese men. Based on the Guangzhou Biobank Cohort Study (GBCS), 4792 men with valid ADH2, ALDH2 genotypes were included, and genotyping of rs1229984 ADH2 and rs671 ALDH2 (AA, AG/GA or GG) was performed using a Sequenom Mass-Array platform. Information on socio-demographics and lifestyle factors, including alcohol use, was obtained from a questionnaire, and blood pressure was measured. Among alcohol drinkers, systolic and diastolic blood pressure (SBP and DBP) and mean arterial pressure (MAP) were highest for men with the GG ADH2 genotype (136.6, 77.9 and 97.5 mm Hg, respectively), followed by those with the (AA/AG ADH2+GG ALDH2) genotype (133.4, 77.6 and 96.2 mm Hg, respectively) and then the (AA/AG ADH2+AA/AG ALDH2) genotype (SBP=132.6, DBP=76.6 and MAP=95.2 mm Hg) (P for trend ranged 0.025–0.035). After adjustment for potential confounders, as well as frequency or amount of alcohol use, men with the GG ADH2 genotype were more likely to have hypertension (odds ratio (OR)=1.62, 95% confidence interval 1.15–2.28) as were men with the (AA/AG ADH2+AA/AG ALDH2) genotype (OR=1.40, 95% confidence interval 1.01–1.96) compared with men with the (AA/AG ADH2+GG ALDH2) genotype). ADH2 or ALDH2 genotypes were unrelated to hypertension among those who never drink alcohol. ADH2 genotype influences blood pressure and risk of hypertension among male alcohol drinkers, suggesting that the hypertensive effect of alcohol is due to ethanol rather than acetaldehyde.

Genetic polymorphisms of alcohol dehydrogenase-1B and aldehyde dehydrogenase-2 and liver cirrhosis, chronic calcific pancreatitis, diabetes mellitus, and hypertension among Japanese alcoholic men

BACKGROUND

The presence of the less-active form of alcohol dehydrogenase-1B encoded by ADH1B*1/*1 (vs. *2 allele) and active form of aldehyde dehydrogenase-2 (ALDH2) encoded by ALDH2*1/*1 (vs. *2 allele) increases the risk of alcoholism in East Asians.

METHODS

The subjects in this cross-sectional survey were 1,902 Japanese alcoholic men (≥40 years) who underwent ADH1B/ALDH2 genotyping.

RESULTS

Age-adjusted daily alcohol consumption did not differ according to the ADH1B/ALDH2 genotypes. The age-adjusted odds ratios (AORs; 95% confidence interval) for liver cirrhosis (LC; n = 359, 1.58 [1.19 to 2.09]), chronic calcific pancreatitis (CP; n = 80, 2.24 [1.20 to 4.20]), and diabetes mellitus (DM; n = 383, 1.51 [1.15 to 1.99]) were higher in the ADH1B*2 allele carriers than in the ADH1B*1/*1 carriers. The AORs for LC (1.43 [1.01 to 2.02]), CP (1.68 [0.80 to 3.53]), DM (1.63 [1.15 to 2.30]), and hypertension (HT; n = 495, 1.52 [1.11 to 2.07]) were higher in the ALDH2*1/*1 carriers than in the ALDH2*1/*2 carriers. The ADH1B*2-associated AOR for LC was 2.08 (1.46 to 2.94) among those aged 40 to 59 years, but 0.89 (0.56 to 1.43) among those aged 60 years or over, and the interaction between ADH1B genotype and age on the LC risk was significant (p = 0.009). When the group with non-LC and no/mild fibrosis was used as controls, the ADH1B*2-associated AORs increased according to the severity of their liver disease: 1.67 (1.32 to 2.11) for the group with non-LC and serum type IV collagen values ≥200 ng/ml, 1.81 (1.24 to 2.63) for the group of Child-Pugh class A LC, and 3.17 (1.98 to 5.07) for the group with Child-Pugh class B/C LC. Anti-hepatitis C virus (HCV) antibody was positive in 103 patients, and the groups with a high anti-HCV antibody titer and either the ADH1B*2/*2 genotype or the ALDH2*1/*1 genotype had the highest AORs (8.83 and 4.90, respectively). The population attributable fraction (PAF) due to the ADH1B*2 allele was 29% for LC, 47% for CP, and 27% for DM, and the PAF due to the ALDH2*1/*1 genotype was 26% for LC, 34% for DM, and 30% for HT.

CONCLUSIONS

The ADH1B*2 allele increased the AORs for LC, CP, and DM of the alcoholics, and the ALDH2*1/*1 genotype increased their AORs for LC, DM, and HT. HCV infection and genetic susceptibility had a synergistic effect on the AOR for LC.

Alcohol dehydrogenase-1B genotype (rs1229984) is a strong determinant of the relationship between body weight and alcohol intake in Japanese alcoholic men

BACKGROUND

The calories in alcoholic beverages consumed by alcoholics are a major energy source and a strong modifier of their body weight. Genetic polymorphisms of alcohol dehydrogenase-1B (ADH1B) and aldehyde dehydrogenase-2 (ALDH2) affect susceptibility to alcoholism and may affect body weight via gene-associated differences in fuel utilization in alcoholics.

METHODS

We evaluated associations between ADH1B/ALDH2 genotypes and the body weight and body mass index (BMI) of 1,301 Japanese alcoholic men at the time of their first visit to an addiction center.

RESULTS

Median (25th to 75th) caloric intake in the form of alcoholic beverages was 864 (588 to 1,176) kcal/d. Age-adjusted caloric intake did not differ according to ADH1B/ALDH2 genotypes. The body weight and BMI values showed that the ADH1B*2/*2 and *1/*2 carriers (n = 939) were significantly leaner than the ADH1B*1/*1 carriers (n = 362) irrespective of age, drinking, smoking, and dietary habits. The age-adjusted body weight values of the ADH1B*2/*2, ADH1B*1/*2, and ADH1B*1/*1 carriers were 58.4 ± 0.4, 58.7 ± 0.5, and 63.6 ± 0.5 kg, respectively (ADH1B*2 vs. ADH1B*1/*1 carriers, p < 0.0001), and the corresponding BMI values were 21.0 ± 0.1, 21.0 ± 0.1, and 22.9 ± 0.2 kg/m(2) , respectively (ADH1B*2 vs. ADH1B*1/*1 carriers, p < 0.0001). No effects of inactive ALDH2 on body weight or BMI were observed. A multivariate analysis showed that BMI decreased by 0.35 per 10-year increase in age, by 1.73 in the presence of the ADH1B*2 allele, by 1.55 when the preferred beverage was whiskey, and by 0.19 per +10 cigarettes/d and that it increased by 0.10 per +22 g ethanol (EtOH)/d and by 0.41 per increase in category of frequency of milk intake (every day, occasionally, rarely, and never). The increase in BMI as alcohol consumption increased was significantly smaller in the ADH1B*2 group than in the ADH1B*1/*1 group (p = 0.002).

CONCLUSIONS

ADH1B genotype was a strong determinant of body weight in the alcoholics. The more rapid EtOH elimination associated with the ADH1B*2 allele may result in less efficient utilization of EtOH as an energy source in alcoholics.

Common ALDH2 genetic variants predict development of hypertension in the SAPPHIRe prospective cohort: gene-environmental interaction with alcohol consumption

Background

Genetic variants near/within the ALDH2 gene encoding the mitochondrial aldehyde dehydrogenase 2 have been associated with blood pressure and hypertension in several case–control association studies in East Asian populations.

Methods

Three common tag single nucleotide polymorphisms (tagSNP) in the ALDH2 gene were genotyped in 1,134 subjects of Chinese origin from the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) family cohort. We examined whether the ALDH2 SNP genotypes predicted the development of hypertension in the prospective SAPPHIRe cohort.

Results

Over an average follow-up period of 5.7 years, carriers homozygous for the rs2238152 T allele in the ALDH2 gene were more likely to progress to hypertension than were non-carriers (hazard ratio [HR], 2.88, 95% confidence interval [CI], 1.06-7.84, P = 0.03), corresponding to a population attributable risk of ~7.1%. The risk associated with the rs2238152 T allele were strongest in heavy/moderate alcohol drinkers and was reduced in non-drinkers, indicating an interaction between ALDH2 genetic variants and alcohol intake on the risk of hypertension (P for interaction = 0.04). The risk allele was associated with significantly lower ALDH2 gene expression levels in human adipose tissue.

Conclusion

ALDH2 genetic variants were associated with progression to hypertension in a prospective Chinese cohort. The association was modified by alcohol consumption.

Acetaldehyde dehydrogenase 2 SNP rs671 and susceptibility to essential hypertension in Mongolians: a case control study

Mongolians are known as heavy drinkers, and they have a high incidence of essential hypertension, which may be an associated pathology. We examined a possible association of essential hypertension and polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene in Mongolians from Inner Mongolia. Single nucleotide polymorphism rs671 of ALDH2 was detected by TaqMan PCR in 91 essential hypertensive patients (44 males and 47 females) and 70 healthy Mongolians (37 males and 33 females). Frequencies of the ALDH2*1/1 genotype and the ALDH2*1 allele in patients (91.2 and 95.6%, respectively) were significantly higher than in controls (78.6 and 89.3%; P < 0.05), while frequencies of ALDH2*1/2 genotype and ALDH2*2 allele in patients (8.79 and 4.4%) were much lower than in controls (21.4 and 10.7%; P < 0.05). Frequencies of ALDH2*1/1 genotype and ALDH2*1 allele in female patients (95.8 and 94.9%) were higher than in female controls (70.0 and 84.9%; P < 0.05); frequencies of the ALDH2*1/2 genotype and the ALDH2*2 allele in female patients (4.25 and 2.13%) were lower than in female controls (30.3 and 15.2%, P < 0.05). There was no significant difference in male subjects. ALDH2*2/2 was not found in any of the subjects. We conclude that ALDH2 polymorphism is associated with essential hypertension in Mongolians, especially in female Mongolians. ALDH2*2 was found to be a negative risk factor for essential hypertension in Mongolians from Inner Mongolia.

Assignment of grouped exposure levels for trend estimation in a regression analysis of summarized data

For performing regression analysis of summarized response data containing grouped intervals of exposure, many researchers use pre-assigned doses such as the median values of each interval. However, the trend estimate is considerably sensitive to the choice of the assigned values. In this paper, we propose a method to assign the values to obtain a more accurate regression coefficient applying the likelihood approach. Numerical illustrations and comparisons through simulations showed that the proposed dose assignment can yield better estimates of trend in the regression analysis of two variants than that obtained by the conventional assignment methods such as those that use median values. In particular, for the data of a case-control study, the proposed dose improved the accuracy of the procedures such as that developed by Greenland and Longnecker (1992) compared with the conventional pre-assigned dose.

Polymorphisms of alcohol metabolizing enzymes in indigenous Mexican population: unusual high frequency of CYP2E1*c2 allele

BACKGROUND

Alcohol abuse represents the major identified etiological factor of cirrhosis in México. ADH1B, ALDH2, and CYP2E1 have been considered candidate genes in alcohol-related diseases. Controversial results probably due to ethnic differences, among other factors, have been reported. Mexican Mestizos (MES) derive from the combination of indigenous, Spaniard, and African genes. Huichols (HUI) constitute an indigenous group from western Mexico with no racial admixture. We determined ADH1B*2, ALDH2*2, and CYP2E1*c2 allele frequencies in healthy HUI and MES from western Mexico. Lipid and hepatic profile were also carried out.

METHODS

One hundred and one HUI and 331 MES subjects were studied. Genotype and allele frequency were assessed through polymerase chain reaction-restriction fragment length polymorphism after DNA isolation from peripheral leukocytes. Commercial kits for lipid and hepatic determinations were used.

RESULTS

Polymorphic allele distribution in HUI was: 0%ADH1B*2, 0.5%ALDH2*2, 51.5%CYP2E1*c2; in MES: 3.4%ADH1B*2, 0%ALDH2*2, 16.1%CYP2E1*c2. Frequency of ADH1B*2 was statistically (p < 0.001) lower in HUI than MES. CYP2E1*c2 polymorphic allele was significantly higher (p < 0.0001) in HUI than MES. Hepatic profile was normal in both groups. HUI showed a better lipid profile than MES independently of genotype.

CONCLUSIONS

Huichols exhibited the highest CYP2E1*c2 allele frequency of the world documented up to this date; meanwhile, ADH1B*2 and ALDH2*2 were practically absent. This feature could be useful in the understanding of Mexican population gene composition, alcohol metabolism, and alcoholic liver disease development. However, further association studies are necessary. The heterogeneity of Mexican population was evidenced by the significantly different distribution of CYP2E1*c2 allele observed among different regions of the country. Lipid and hepatic values were not associated to genotype. This report constitutes the first study dealing with gene polymorphisms of alcohol metabolizing enzymes conducted in HUI.

Sensitivity of circulatory response to alcohol influences the relationship between alcohol consumption and blood pressure in Orientals

There is a genetic difference in sensitivity to alcohol in Orientals, which is known to be mainly due to polymorphisms of alcohol-metabolizing enzymes such as aldehyde dehydrogenase. Habitual alcohol drinking is a risk factor for hypertension. However, it has not been determined whether individual sensitivity to alcohol influences the relationship between alcohol consumption and blood pressure. In this study, the relationship between amount of alcohol consumption and blood pressure was compared between groups of subjects with low and high sensitivities of circulatory response to alcohol. Sensitivity to alcohol in subjects (306 male workers) was evaluated by a self-administered questionnaire on symptoms (skin flushing and palpitation) that appear when drinking alcohol. Weight, height and blood pressure were measured. In subjects with high sensitivity to alcohol, systolic blood pressure was significantly higher in the subgroup of moderate-to-heavy drinkers (30 g/day or more) than in the subgroups of non-drinkers and light drinkers (less than 30 g/day). On the other hand, in subjects with low sensitivity to alcohol, systolic blood pressure in the subgroup of non-drinkers was not significantly different from that in the subgroups of light drinkers and moderate-to-heavy drinkers. The amount of daily alcohol consumption was significantly correlated with both systolic and diastolic blood pressures in subjects with high sensitivity to alcohol but not in subjects with low sensitivity to alcohol. Pressor effects of alcohol drinking on blood pressure were significant only in subjects with high sensitivity to alcohol, suggesting that there is a greater risk of development of hypertension from drinking large amounts of alcohol in people with high sensitivity to alcohol.

Gene-environmental interaction regarding alcohol-metabolizing enzymes in the Japanese general population

Epidemiological studies have shown that excessive alcohol consumption is a potent risk factor to develop hypertension. In addition, some polymorphisms of the alcohol metabolism genes have been reported to exert significant impacts on the risk of alcoholism. We investigate the relevance of genetic susceptibility to drinking behavior and its influence on the sensitivity to pressor effects of alcohol in the Japanese general population. We initially screened SNPs in four candidate genes by resequencing. From 35 SNPs thus identified, 10 tag SNPs were selected and used for large-scale association analysis in a total of 5724 subjects. Among the SNPs tested, significant association (P<0.001) with drinking behavior was observed for ADH1B Arg47His (rs1229984) and ALDH2 Glu487Lys (rs671) polymorphisms. All subjects with Lys homozygote (AA genotype) of rs671 turned out to be nondrinkers and the combination of two SNP genotypes appeared to substantially influence people's drinking behavior in a synergistic manner. rs671 was significantly associated with blood pressure (P=0.0001-0.0491) in subgroups of drinkers. In the context of gene-environment interaction, our data clearly show the genetic impacts of two SNPs on drinking behavior and of one SNP on the sensitivity to the pressor effects of alcohol in the Japanese general population.

Alcohol intake and blood pressure: a systematic review implementing a Mendelian randomization approach

BACKGROUND

Alcohol has been reported to be a common and modifiable risk factor for hypertension. However, observational studies are subject to confounding by other behavioural and sociodemographic factors, while clinical trials are difficult to implement and have limited follow-up time. Mendelian randomization can provide robust evidence on the nature of this association by use of a common polymorphism in aldehyde dehydrogenase 2 (ALDH2) as a surrogate for measuring alcohol consumption. ALDH2 encodes a major enzyme involved in alcohol metabolism. Individuals homozygous for the null variant (*2*2) experience adverse symptoms when drinking alcohol and consequently drink considerably less alcohol than wild-type homozygotes (*1*1) or heterozygotes. We hypothesise that this polymorphism may influence the risk of hypertension by affecting alcohol drinking behaviour.

METHODS AND FINDINGS

We carried out fixed effect meta-analyses of the ALDH2 genotype with blood pressure (five studies, n = 7,658) and hypertension (three studies, n = 4,219) using studies identified via systematic review. In males, we obtained an overall odds ratio of 2.42 (95% confidence interval [CI] 1.66-3.55, p = 4.8 x 10(-6)) for hypertension comparing *1*1 with *2*2 homozygotes and an odds ratio of 1.72 (95% CI 1.17-2.52, p = 0.006) comparing heterozygotes (surrogate for moderate drinkers) with *2*2 homozygotes. Systolic blood pressure was 7.44 mmHg (95% CI 5.39-9.49, p = 1.1 x 10(-12)) greater among *1*1 than among *2*2 homozygotes, and 4.24 mmHg (95% CI 2.18-6.31, p = 0.00005) greater among heterozygotes than among *2*2 homozygotes.

CONCLUSIONS

These findings support the hypothesis that alcohol intake has a marked effect on blood pressure and the risk of hypertension.

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.

Lack of association between ADH3 polymorphism, alcohol intake, risk factors and carotid intima-media thickness

OBJECTIVE

We assess the relationships between alcohol dehydrogenase 3 (ADH3) polymorphism, alcohol consumption and cardiovascular risk factor levels.

METHODS

In a representative population sample from Southwestern France (614 men, 567 women, age 49.7+/-8.5 years), alcohol intake was assessed by questionnaire.

RESULTS

Alcohol consumption was significantly related with higher levels of total and HDL cholesterol, triglycerides, apolipoprotein A-I in men and with higher levels of HDL cholesterol in women. Also, an inverse relationship between alcohol consumption and intima-media thickness was found in men. Conversely, in both genders, no differences were found between ADH3 genotypes regarding all cardiovascular risk factors studied and carotid intima-media thickness. Also, in both genders, no significant ADH3xalcohol interaction was found for all variables, and further adjustment on age, body mass index, educational level, smoking status or after excluding subjects on hypolipidemic or antihypertensive drug treatment did not change the results.

CONCLUSION

We found no interaction between the ADH3 polymorphism and alcohol intake on cardiovascular risk factor levels and atherosclerotic markers in Southwestern France.

Polymorphism of methylenetetrahydrofolate reductase gene (C677T MTHFR) is not a confounding factor of the relationship between serum uric acid level and the prevalence of hypertension in Japanese men

BACKGROUND

The association between serum uric acid (UA) and the prevalence of hypertension, and the relationship between methylenetetrahydrofolate reductase (MTHFR) polymorphism and hypertension remains unclear. The aim of the present study was to investigate whether the C677T MTHFR mutation genotype (VV) is independently associated with the prevalence of hypertension or blood pressure (BP), and examined any interaction of MTHFR and UA with BP.

METHODS AND RESULTS

Participants were randomly selected from all residents (aged 40-69 years) in a rural county of Japan, and the data for the men (n=335) were analyzed. ;Hypertension' was defined as systolic BP >or=140 and/or diastolic BP >or=90 mmHg and/or being administered antihypertensive medication. Serum UA level was independently associated with the prevalence of hypertension (odds ratio (95% confidence interval) =2.7 (1.2-5.9), p=0.047) for the highest tertile of serum UA (>or=398.5 micromol/L (6.7 mg/dl)) vs that of the lowest tertile (<321.2 micromol/L (5.4 mg/dl)), but the MTHFR mutation was not independently associated with prevalence of hypertension or BP. No interaction of the MTHFR mutation and serum UA with BP was found.

CONCLUSIONS

The mutation of C677T MTHFR was not independently associated with the prevalence of hypertension or BP levels although serum UA was. Furthermore, the relationship between serum UA and BP was not modulated by the MTHFR mutation in Japanese men.

Gly395Arg Polymorphism of PPAR.ALPHA. Gene Was Not Detected in Japanese Population of 729 Individuals

Peroxisome proliferator-activated receptor a (PPARalpha) is a member of the nuclear receptor superfamily and participates in the regulation of key proteins involved in lipid metabolism, fatty acid oxidation, homeostasis, and inflammation. Several polymorphisms of the human PPARalpha gene, such as Leu162Val polymorphism and Val227Ala polymorphism, have been described in different races. Recently, another PPARalpha polymorphism Gly395Arg polymorphism has been reported in Caucasian and African subjects. Using the Invader assay, we searched for this polymorphism in 729 Japanese adults randomly selected in a rural population. Although the synthesized oligonucleotides of each polymorphism could be distinguished clearly, all 729 individuals had the Gly (G) allele and none had the Arg (C) allele. These data suggest that there is racial variability in the frequencies of PPARalpha gene polymorphisms.

The 2.3 genotype of ESRRA23 of the ERR alpha gene is associated with a higher BMI than the 2.2 genotype

ERR alpha (NR3B1) is an orphan nuclear receptor believed to be involved in energy metabolism and obesity. A 23-base pair sequence in the 5'-flanking region of the ERR alpha gene, referred to as ESRRA23, is polymorphic in human chromosomes. Here, we investigated the influence of the ESRRA23 polymorphism on obesity in 703 Japanese individuals by analyzing indices of obesity and related lifestyle factors. The frequency of genotypes was similar to that reported in whites. The 2.3-genotype was associated with a significantly higher BMI than was the 2.2-genotype. An increased number of ESRRA23 repeats may be a genetic factor in human obesity.

Epidemiological evidence that acetaldehyde plays a significant role in the development of decreased serum folate concentration and elevated mean corpuscular volume in alcohol drinkers

BACKGROUND

Elevated mean corpuscular volume (MCV) is a traditional biological marker for alcohol abuse and alcoholism, but the underlying mechanism is unclear. Three recent epidemiologic studies consistently showed that MCV was elevated by alcohol drinking more markedly among individuals with genetically inactive aldehyde dehydrogenase-2 (ALDH2) (encoded by ALDH2*2 mutant allele) than those with active ALDH2 (encoded by ALDH2*1/2*1 genotype), suggesting that the elevated MCV was etiologically linked to acetaldehyde exposure. The purpose of the present study was to clarify further this relationship by examining the status of folate and vitamin B12.

METHODS

The study participants were 159 men who were aged 40 to 69 years and randomly selected from a Japanese rural population. The genetic polymorphism of ALDH2 was determined by PCR-restriction fragment length polymorphism method; data on alcohol drinking and other lifestyles were collected using a structured questionnaire; serum concentrations of folate and vitamin B12 were measured using the protein competitive reaction method, and blood cell counts were measured by routine methods. A multiple linear regression model was used to analyze the data.

RESULTS

: The relationship between alcohol drinking and serum folate concentration was significantly different between ALDH2 genotypes, indicating that the reduction of serum folate by alcohol drinking was more marked in men with ALDH2*1/2*2 than those with ALDH2*1/2*1. The relationship between alcohol drinking and elevated MCV was significantly stronger in men with ALDH2*1/2*2 than those with ALDH2*1/2*1 even after adjustment for serum folate and vitamin B12 concentrations.

CONCLUSIONS

These findings indicate that acetaldehyde plays a significant role in the development of decreased serum folate concentration and elevated MCV by alcohol drinking.

Hypertension Treatment Guidelines: Practical Implications

The focus of blood pressure (BP) lowering is to prevent or reduce the risk for cardiovascular and renal events. This rationale forms the basis for the recent guideline statements issued by the Seventh Joint National Committee, the American Diabetes Association, the European Society of Hypertension, and the Kidney Disease Outcomes Quality Initiative. The goal BP in the majority of hypertensive patients should be less than 140/90 mm Hg, with a lower goal of less than 130/80 mm Hg in patients with diabetes or kidney disease. Meta-analyses of clinical trials with renal end points make it clear that the presence of 1 gram or more of proteinuria mandates a BP approaching 115 mm Hg to slow the progression of advanced nephropathy adequately. Compelling indications also exist for the use of certain antihypertensive agents in the setting of kidney dysfunction, diabetes, heart failure, and coronary artery disease. Initiation with 2 antihypertensive agents should be considered strongly for patients with a BP of more than 20 mm Hg greater than the systolic BP goal. This means that those with a goal BP of less than 130 mm Hg should be started on 2 antihypertensive medications with complementary actions when the systolic BP is 150 mm Hg or greater. In patients with kidney disease, reaching the BP goal requires multiple agents that should include an appropriate diuretic and an agent that blocks the renin-angiotensin-aldosterone system to slow the progression of kidney disease.

Role of human aldehyde dehydrogenases in endobiotic and xenobiotic metabolism

The human genome contains at least 17 genes that are members of the aldehyde dehydrogenase (ALDH) superfamily. These genes encode NAD(P)(+)-dependent enzymes that oxidize a wide range of aldehydes to their corresponding carboxylic acids. Aldehydes are highly reactive molecules that are intermediates or products involved in a broad spectrum of physiologic, biologic, and pharmacologic processes. Aldehydes are generated during retinoic acid biosynthesis and the metabolism of amino acids, lipids, carbohydrates, and drugs. Mutations in several ALDH genes are the molecular basis of inborn errors of metabolism and contribute to environmentally induced diseases.