Alcohol consumption alters insulin secretion and cardiac autonomic activity

Elevated levels of alcohol dehydrogenase aggravate ethanol-evoked cardiac remodeling and contractile anomalies through FKBP5-yap-mediated regulation of ferroptosis and ER stress

Alcohol intake provokes severe organ injuries including alcoholic cardiomyopathy with hallmarks of cardiac remodeling and contractile defects. This study examined the toxicity of facilitated ethanol metabolism in alcoholism-evoked changes in myocardial morphology and contractile function, insulin signaling and various cell death domains using cardiac-selective overexpression of alcohol dehydrogenase (ADH). WT and ADH mice were offered an alcohol liquid diet for 12 weeks prior to assessment of cardiac geometry, function, ER stress, apoptosis and ferroptosis. Alcohol intake provoked pronounced glucose intolerance, cardiac remodeling and contractile anomalies with apoptosis, ER stress, and ferroptosis, the effects were accentuated by ADH with the exception of global glucose intolerance. Hearts from alcohol ingesting mice displayed dampened insulin-stimulated phosphorylation of insulin receptor (tyr1146) and IRS-1 (tyrosine) along with elevated IRS-1 serine phosphorylation, the effect was augmented by ADH. Alcohol challenge dampened phosphorylation of Akt and GSK-3β, and increased phosphorylation of c-Jun and JNK, the effects were accentuated by ADH. Alcohol challenge promoted ER stress, FK506 binding protein 5 (FKBP5), YAP, apoptosis and ferroptosis, the effects were exaggerated by ADH. Using a short-term ethanol challenge model (3 g/kg, i.p., twice in three days), we found that inhibition of FKBP5-YAP signaling or facilitated ethanol detoxification by Alda-1 alleviated ethanol cardiotoxicity. In vitro study revealed that the ethanol metabolite acetaldehyde evoked cardiac contractile anomalies, lipid peroxidation, and apoptosis, the effects of which were mitigated by Alda-1, inhibition of ER stress, FKBP5 and YAP. These data suggest that facilitated ethanol metabolism via ADH exacerbates alcohol-evoked myocardial remodeling, functional defects, and insulin insensitivity possibly through a FKBP5-YAP-associated regulation of ER stress and ferroptosis.

Patients with AUD exhibit dampened heart rate variability during sleep as compared to social drinkers

Chronic heavy alcohol use profoundly affects the cardiovascular system, contributing to several life-threatening cardiovascular diseases. Heart rate variability (HRV), or the fluctuations in heart rate, reflects dynamic autonomic nervous system processes that change to meet biological demands and environmental challenges. In the current study, we examined whether HRV metrics are altered in alcohol use disorder (AUD) during waking and sleeping with passive biomonitoring as participants went about their daily lives. Social drinkers (standard deviation: n = 10, 5 female) and treatment-seeking individuals with moderate to severe AUD (n = 16, 7 female) provided continuous, real-world heart rate monitoring for 5 days of monitoring on average (M = 5.27 ± 2.22). Five indices of respiration and HRV-respiratory sinus arrhythmia (RSA) amplitude, high frequency (HF), low frequency (LF), HF/LF ratio, root-mean-square standard deviation (RMSSD), and standard deviation of the N-N intervals (SDNN)-were analyzed separately for waking and sleeping hours. Both RMSSD and SDNN decreased the longer the participants were awake (Ps < .013). During sleeping hours, HF, RSA amplitude, RMSSD, and SDNN were significantly higher in light social drinkers as compared to patients with AUD (all Ps < .009), indicating higher parasympathetic activation during sleep in the SD versus AUD group. Sleep and waking HRV measures were significantly correlated with patient-reported symptoms of depression and sleep difficulties in the AUD group (Ps < .05). This natural observational study utilizing continuous autonomic biomonitoring in the real world indicates parasympathetic dysfunction that is clearly detectable during sleep in AUD and HRV measures, which are also related to clinical, patient-related symptoms of AUD.

The potential effects of HECTD4 variants on fasting glucose and triglyceride levels in relation to prevalence of type 2 diabetes based on alcohol intake

Excessive alcohol intake is an important cause of major public health problem in East Asian countries. Growing evidence suggests that genetic factors are associated with alcohol consumption and the risk for alcohol-associated disease, and these factors contribute to the risk of developing chronic diseases, including diabetes. This study aims to investigate the association of type 2 diabetes with genetic polymorphisms within HECTD4 based on alcohol exposure. We performed a genome-wide association study involving the cohorts of the KoGES-HEXA study (n = 50,028) and Ansan and Ansung study (n = 7,980), both of which are prospective cohort studies in Korea. The top three single-nucleotide polymorphisms (SNPs) of the HECTD4 gene, specifically rs77768175, rs2074356 and rs11066280, were found to be significantly associated with alcohol consumption. We found that individuals carrying the variant allele in these SNPs had lower fasting blood glucose, triglyceride, and GGT levels than those with the wild-type allele. Multiple logistic regression showed that statistically significant associations of HECTD4 gene polymorphisms with an increased risk of type 2 diabetes were found in drinkers. Namely, these SNPs were associated with decreased odds of diabetes in the presence of alcohol consumption. As a result of examining the effect of alcohol on the expression of the HECTD4 gene, ethanol increased the expression of HECTD4 in cells, but the level was decreased by NAC treatment. Similar results were obtained from liver samples of mice treated with alcohol. Moreover, a loss of HECTD4 resulted in reduced levels of CYP2E1 and lipogenic gene expression in ethanol-treated cells, while the level of ALDH2 expression increased, indicating a reduction in ethanol-induced hepatotoxicity.

Effects of Alcohol Reduction Interventions on Blood Pressure

PURPOSE OF REVIEW

Much of alcohol's purported negative impact on a population's health can be attributed to its association with increased blood pressure, rates of hypertension, and incidence of cardiovascular disease (CVD). Less attention, however, has been placed on the association of the positive impact of alcohol reduction interventions on physical health.

RECENT FINDINGS

This review delineates the evidence of blood pressure reductions as a function of alcohol reduction interventions based on current care models. The findings of this review suggest two things: (1) sufficient evidence exists for a relationship between alcohol reductions and blood pressure generally, and (2) little evidence exists for the relationship between alcohol reductions and blood pressure for any one care model currently employed in the health system. The evidence base would benefit from more studies using established alcohol reduction interventions examining the impact of these interventions on blood pressure.

Disentangling the impact of alcohol use and hepatitis C on insulin action in Latino individuals

BACKGROUND

Alcohol, insulin resistance (IR), and hepatitis C (HCV) are all significant contributors to adverse outcomes of chronic liver disease. Latinos are disproportionately affected by these risk factors. We investigated the relationship between alcohol use and insulin action in a prospective cohort of Latino individuals with and without HCV.

METHODS

One hundred fifty-three nondiabetic Latino individuals (60 HCV+, 93 HCV-) underwent clinical evaluation and metabolic testing; 56 had repeat testing over a median follow-up of 1.5 years. Peripheral IR and hepatic IR were measured via steady-state plasma glucose (SSPG) and endogenous glucose production during a two-step, 240-min insulin suppression test. Insulin secretion (IS) was measured using the graded glucose infusion test. Alcohol use was categorized as none, moderate (≤1 drink/day for women and ≤2 drinks/day for men), and heavy (>moderate). Multivariable models including HCV status assessed associations of alcohol use with baseline SSPG, hepatic IR and IS, and changes in these parameters over time.

RESULTS

Overall, the median age was 44 years, 63.4% were male, 66.7% overweight/ obese, and 31.9% had heavy lifetime alcohol use while 60.4% had moderate lifetime alcohol use. SSPG and IS were similar by levels of alcohol use at baseline and alcohol use was not statistically significantly associated with change in these measures over time. However, lifetime daily heavy alcohol use (vs. not heavy, coef 2.4 μU-mg/kg-min-ml, p = 0.04) and HCV status (coef 4.4 μU-mg/kg-min-ml, p = 0.0003) were independently associated with higher baseline hepatic IR, and current heavy alcohol use was associated with greater change in hepatic IR in follow-up (coef 5.8 μU-mg/kg-min-ml, p = 0.03).

CONCLUSIONS

In this cohort of Latino individuals, lifetime and current heavy alcohol use influenced hepatic IR and its change over time. Strategies to decrease rates of heavy alcohol use or increase abstinence along with lifestyle modification and anti-HCV therapy to reduce metabolic risk are critical to prevent adverse liver and metabolic outcomes in Latino individuals.

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.

Heart rate variability in alcohol use: A review

BACKGROUND

Prior studies have shown that resting heart rate variability (HRV) is reduced in those with alcohol use disorders (AUD). However, HRV following an acute stressful stimulus (reactive HRV), and the relationship between resting or reactive HRV and drinking, craving and relapse in AUD have received less attention.

METHODS

Studies using HRV in relationship to acute or chronic alcohol consumption were included in this review. Manuscripts that related to alcohol in the context of cardiovascular disease were excluded.

RESULTS

Thirty-three articles were included and findings are presented in healthy social drinkers, moderate/heavy drinkers without AUD and individuals with AUD. Results on resting and reactive HRV were presented separately. Acute alcohol reduced resting HRV in healthy subjects but healthy controls had higher resting HRV then AUD subjects and moderate/heavy drinkers (in some studies). Resting HRV improved in AUD subjects only after at least 4 months of abstinence. AUD subjects had higher reactive HRV scores when compared to controls. In AUD subjects increased reactivity was related to more craving, faster relapse and more negative mood. Reactive HRV showed slower improvement with abstinence in AUD subjects.

CONCLUSIONS

Chronic, heavy alcohol has a negative effect on the autonomic nervous system and may be a sensitive biomarker of craving and relapse.

Association between alcohol consumption pattern and the incidence risk of type 2 diabetes in Korean men: A 12-years follow-up study

Moderate alcohol consumption is generally associated with reduced risk of type 2 diabetes. However, this beneficial effects of alcohol intake remains controversial due to inconsistent results across studies. The analysis was performed using data from the Ansung-Ansan cohort study. We categorized the participants into four groups-based on the baseline (one-point measure; non-drinking, <5 g/day, ≥5, <30 g/day, and ≥30 g/day) and follow-up (consumption pattern; never-drinking, light, moderate, and heavy drinking) measurement. At baseline, ≥30 g/day alcohol consumption increased the risk of incident diabetes (HR: 1.42; 95% CI, 1.10-1.85), but ≥5, <30 g/day alcohol consumption had no effects on the incident diabetes. Meanwhile, when using the alcohol consumption pattern, a heavy-drinking pattern increased the risk of incident diabetes (HR = 1.32, 1.01-1.73), but the light and moderate consumption pattern was associated with a reduced risk of type 2 diabetes (HR: 0.66; 0.50-0.87 and HR: 0.74; 0.57-0.95, respectively). At the end point of follow-up, the insulinogenic index (IGI), but not the insulin sensitivity index (ISI), differed among the groups. Alcohol consumption pattern had a J-shaped association with the incident type 2 diabetes in Korean men. The IGI showed an inverted J-shaped association according to alcohol drinking pattern, but the ISI was not a J-shape.

The effect of a reduction in alcohol consumption on blood pressure: a systematic review and meta-analysis

BACKGROUND

Although it is well established that heavy alcohol consumption increases the risk of hypertension, little is known about the effect of a reduction of alcohol intake on blood pressure. We aimed to assess the effect of a reduction in alcohol consumption on change in blood pressure stratified by initial amount of alcohol consumption and sex in adults.

METHODS

In this systematic review and meta-analysis, we searched MedLine, Embase, CENTRAL, and ClinicalTrials.gov from database inception up to July 13, 2016, for trials investigating the effect of a change of alcohol consumption on blood pressure in adults using keywords and MeSH terms related to alcohol consumption, blood pressure, and clinical trials, with no language restrictions. We also searched reference lists of identified articles and published meta-analyses and reviews. We included full-text articles with original human trial data for the effect of a change of alcohol consumption on blood pressure in adults, which reported a quantifiable change in average alcohol consumption that lasted at least 7 days and a corresponding change in blood pressure. We extracted data from published reports. We did random-effects meta-analyses stratified by amount of alcohol intake at baseline. All meta-analyses were done with Stata (version 14.1). For the UK, we modelled the effect of a reduction of alcohol consumption for 50% of the population drinking more than two standard drinks per day (ie, 12 g pure alcohol per drink).

FINDINGS

36 trials with 2865 participants (2464 men and 401 women) were included. In people who drank two or fewer drinks per day, a reduction in alcohol was not associated with a significant reduction in blood pressure; however, in people who drank more than two drinks per day, a reduction in alcohol intake was associated with increased blood pressure reduction. Reduction in systolic blood pressure (mean difference -5·50 mm Hg, 95% CI -6·70 to -4·30) and diastolic blood pressure (-3·97, -4·70 to -3·25) was strongest in participants who drank six or more drinks per day if they reduced their intake by about 50%. For the UK, the results would translate into more than 7000 inpatient hospitalisations and 678 cardiovascular deaths prevented every year.

INTERPRETATION

Reducing alcohol intake lowers blood pressure in a dose-dependent manner with an apparent threshold effect. Implementation of effective alcohol interventions in people who drink more than two drinks per day would reduce the disease burden from both alcohol consumption and hypertension, and should be prioritised in countries with substantial alcohol-attributable risk.

FUNDING

National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health (NIH).

Chronic binge alcohol administration impairs glucose-insulin dynamics and decreases adiponectin in asymptomatic simian immunodeficiency virus-infected macaques

Alcohol use disorders (AUDs) frequently exist among persons living with HIV/AIDS. Chronic alcohol consumption, HIV infection, and antiretroviral therapy (ART) are independently associated with impairments in glucose-insulin dynamics. Previous studies from our laboratory have shown that chronic binge alcohol (CBA) administration decreases body mass index, attenuates weight gain, and accentuates skeletal muscle wasting at end-stage disease in non-ART-treated simian immunodeficiency virus (SIV)-infected male rhesus macaques. The aim of this study was to investigate whether CBA and ART alone or in combination alter body composition or glucose-insulin dynamics in SIV-infected male rhesus macaques during the asymptomatic phase of SIV infection. Daily CBA or sucrose (SUC) administration was initiated 3 mo before intrarectal SIV inoculation and continued until the study end point at 11 mo post-SIV infection. ART or placebo was initiated 2.5 mo after SIV infection and continued until study end point. Four treatment groups (SUC/SIV ± ART and CBA/SIV ± ART) were studied. CBA/SIV macaques had significantly decreased circulating adiponectin and resistin levels relative to SUC/SIV macaques and reduced disposition index and acute insulin response to glucose, insulin, and C-peptide release during frequently sampled intravenous glucose tolerance test, irrespective of ART status. No statistically significant differences were observed in homeostatic model assessment-insulin resistance values, body weight, total body fat, abdominal fat, or total lean mass or bone health among the four groups. These findings demonstrate CBA-mediated impairments in glucose-insulin dynamics and adipokine profile in asymptomatic SIV-infected macaques, irrespective of ART.

Acute effects of traditional Japanese alcohol beverages on blood glucose and polysomnography levels in healthy subjects

Background. Alcohol consumption is a lifestyle factor associated with type 2 diabetes. This relationship is reportedly different depending on the type of alcohol beverage. The purpose of this study was to examine the acute effects of traditional Japanese alcohol beverages on biochemical parameters, physical and emotional state, and sleep patterns.

Methods. Six healthy subjects (three men and three women; age, 28.8 ± 9.5 years; body mass index, 21.4 ± 1.6 kg/m²) consumed three different types of alcohol beverages (beer, shochu, and sake, each with 40 g ethanol) or mineral water with dinner on different days in the hospital. Blood samples were collected before and 1, 2, and 12 h after drinking each beverage, and assessments of physical and emotional state were administered at the same time. In addition, sleep patterns and brain waves were examined using polysomnography.

Results. Blood glucose levels at 1 h and the 12-h area under the curve (AUC) value after drinking shochu were significantly lower than that with water and beer. The 12-h blood insulin AUC value after drinking shochu was significantly lower than that with beer. Blood glucose × insulin level at 1 h and the 2-h blood glucose × insulin AUC value with shochu were significantly lower than that with beer. The insulinogenic indexes at 2 h with beer and sake, but not shochu, were significantly higher than that with water. The visual analogue scale scores of physical and emotional state showed that the tipsiness levels with beer, shochu, and sake at 1 h were significantly higher than that with water. These tipsiness levels were maintained at 2 h. The polysomnography showed that the rapid eye movement (REM) sleep latency with shochu and sake were shorter than that with water and beer.

Conclusions. Acute consumption of alcohol beverages with a meal resulted in different responses in postprandial glucose and insulin levels as well as REM sleep latency. Alcohol beverage type should be taken into consideration for people with impaired glucose tolerance.

Impact of Alcohol on Glycemic Control and Insulin Action

Alcohol has profound effects on tissue and whole-body fuel metabolism which contribute to the increased morbidity and mortality in individuals with alcohol use disorder. This review focuses on the glucose metabolic effects of alcohol, primarily in the muscle, liver and adipose tissue, under basal postabsorptive conditions and in response to insulin stimulation. While there is a relatively extensive literature in this area, results are often discordant and extrapolating between models and tissues is fraught with uncertainty. Comparisons between data generated in experimental cell and animals systems will be contrasted with that obtained from human subjects as often times results differ. Further, the nutritional status is also an important component of the sometimes divergent findings pertaining to the effects of alcohol on the regulation of insulin and glucose metabolism. This work is relevant as the contribution of alcohol intake to the development or exacerbation of type 2 diabetes remains ill-defined and a multi-systems approach is likely needed as both alcohol and diabetes affect multiple targets within the body.

The effect of alcohol consumption on insulin sensitivity and glycemic status: a systematic review and meta-analysis of intervention studies

OBJECTIVE

Moderate alcohol consumption is associated with a reduced risk of type 2 diabetes. This reduced risk might be explained by improved insulin sensitivity or improved glycemic status, but results of intervention studies on this relation are inconsistent. The purpose of this study was to conduct a systematic review and meta-analysis of intervention studies investigating the effect of alcohol consumption on insulin sensitivity and glycemic status.

RESEARCH DESIGN AND METHODS

PubMed and Embase were searched up to August 2014. Intervention studies on the effect of alcohol consumption on biological markers of insulin sensitivity or glycemic status of at least 2 weeks' duration were included. Investigators extracted data on study characteristics, outcome measures, and methodological quality.

RESULTS

Fourteen intervention studies were included in a meta-analysis of six glycemic end points. Alcohol consumption did not influence estimated insulin sensitivity (standardized mean difference [SMD] 0.08 [-0.09 to 0.24]) or fasting glucose (SMD 0.07 [-0.11 to 0.24]) but reduced HbA1c (SMD -0.62 [-1.01 to -0.23]) and fasting insulin concentrations (SMD -0.19 [-0.35 to -0.02]) compared with the control condition. Alcohol consumption among women reduced fasting insulin (SMD -0.23 [-0.41 to -0.04]) and tended to improve insulin sensitivity (SMD 0.16 [-0.04 to 0.37]) but not among men. Results were similar after excluding studies with high alcohol dosages (>40 g/day) and were not influenced by dosage and duration of the intervention.

CONCLUSIONS

Although the studies had small sample sizes and were of short duration, the current evidence suggests that moderate alcohol consumption may decrease fasting insulin and HbA1c concentrations among nondiabetic subjects. Alcohol consumption might improve insulin sensitivity among women but did not do so overall.

Lead Intoxication Synergies of the Ethanol-Induced Toxic Responses in Neuronal Cells--PC12

Lead (Pb)-induced neurodegeneration and its link with widespread neurobehavioral changes are well documented. Experimental evidences suggest that ethanol could enhance the absorption of metals in the body, and alcohol consumption may increase the susceptibility to metal intoxication in the brain. However, the underlying mechanism of ethanol action in affecting metal toxicity in brain cells is poorly understood. Thus, an attempt was made to investigate the modulatory effect of ethanol on Pb intoxication in PC12 cells, a rat pheochromocytoma. Cells were co-exposed to biological safe doses of Pb (10 μM) and ethanol (200 mM), and data were compared to the response of cells which received independent exposure to these chemicals at similar doses. Ethanol (200 mM) exposure significantly aggravated the Pb-induced alterations in the end points associated with oxidative stress and apoptosis. The finding confirms the involvement of reactive oxygen species (ROS)-mediated oxidative stress, and impairment of mitochondrial membrane potential, which subsequently facilitate the translocation of triggering proteins between cytoplasm and mitochondria. We further confirmed the apoptotic changes due to induction of mitochondria-mediated caspase cascade. These cellular changes were found to recover significantly, if the cells are exposed to N-acetyl cysteine (NAC), a known antioxidant. Our data suggest that ethanol may potentiate Pb-induced cellular damage in brain cells, but such damaging effects could be recovered by inhibition of ROS generation. These results open up further possibilities for the design of new therapeutics based on antioxidants to prevent neurodegeneration and associated health problems.

Moderate alcohol use and cardiovascular disease from Mendelian randomization

Background

Observational studies show moderate alcohol use negatively associated with ischemic heart disease (IHD) and cardiovascular disease (CVD). However, healthier attributes among moderate users compared to never users may confound the apparent association. A potentially less biased way to examine the association is Mendelian randomization, using alcohol metabolizing genes which influence alcohol use.

Methods

We used instrumental variable analysis with aldehyde dehydrogenase 2 (ALDH2) genotypes (AA/GA/GG) as instrumental variables for alcohol use to examine the association of alcohol use (10 g ethanol/day) with CVD risk factors (blood pressure, lipids and glucose) and morbidity (self-reported IHD and CVD) among men in the Guangzhou Biobank Cohort Study.

Results

ALDH2 genotypes were a credible instrument for alcohol use (F-statistic 74.6). Alcohol was positively associated with HDL-cholesterol (0.05 mmol/L per alcohol unit, 95% confidence interval (CI) 0.02 to 0.08) and diastolic blood pressure (1.15 mmHg, 95% CI 0.23 to 2.07) but not with systolic blood pressure (1.00 mmHg, 95% CI -0.74 to 2.74), LDL-cholesterol (0.03 mmol/L, 95% CI -0.03 to 0.08), log transformed triglycerides (0.03 mmol/L, 95% CI -0.01 to 0.08) or log transformed fasting glucose (0.01 mmol/L, 95% CI -0.006 to 0.03), self-reported CVD (odds ratio (OR) 0.98, 95% CI 0.76 to 1.27) or self-reported IHD (OR 1.10, 95% CI 0.83 to 1.45).

Conclusion

Low to moderate alcohol use among men had the expected effects on most CVD risk factors but not fasting glucose. Larger studies are needed to confirm the null associations with IHD, CVD and fasting glucose.

Habitual alcohol consumption is associated with lower cardiovascular stress responses--a novel explanation for the known cardiovascular benefits of alcohol?

In contrast to heavy alcohol consumption, which is harmful, light to moderate drinking has been linked to reduced cardiovascular morbidity and mortality. Effects on lipid status or clotting do not fully explain these benefits. Exaggerated cardiovascular responses to mental stress are detrimental to cardiovascular health. We hypothesized that habitual alcohol consumption might reduce these responses, with potential benefits. Advanced magnetic resonance techniques were used to accurately measure cardiovascular responses to an acute mental stressor (Montreal Imaging Stress Task) in 88 healthy adults (∼1:1 male:female). Salivary cortisol and task performance measures were used to assess endocrine and cognitive responses. Habitual alcohol consumption and confounding factors were assessed by questionnaire. Alcohol consumption was inversely related to responses of heart rate (HR) (r = -0.31, p = 0.01), cardiac output (CO) (r = -0.32, p = 0.01), vascular resistance (r = 0.25, p = 0.04) and mean blood pressure (r = -0.31, p = 0.01) provoked by stress, but not to stroke volume (SV), or arterial compliance changes. However, high alcohol consumers had greater cortisol stress responses, compared to moderate consumers (3.5 versus 0.7 nmol/L, p = 0.04). Cognitive measures did not differ. Findings were not explained by variations in age, sex, social class, ethnicity, physical activity, adrenocortical activity, adiposity, smoking, menstrual phase and chronic stress. Habitual alcohol consumption is associated with reduced cardiac responsiveness during mental stress, which has been linked to lower risk of hypertension and vascular disease. Consistent with established evidence, our findings suggest a mechanism by which moderate alcohol consumption might reduce cardiovascular disease, but not high consumption, where effects such as greater cortisol stress responses may negate any benefits.

Ethanol causes endoplasmic reticulum stress and impairment of insulin secretion in pancreatic β-cells

Chronic ethanol consumption increases the risk of type 2 diabetes mellitus, and ethanol has been reported to cause insulin resistance and, inconsistently, to reduce insulin secretion. The mechanism(s) underlying the reduction of insulin secretion by ethanol is not known. We used β-cell lines and isolated murine islets to determine the effect of ethanol on insulin content and secretion at low- and high-glucose concentrations, in the presence of KCl, diazoxide, tolbutamide, and regulators of cyclic AMP and protein kinase C (PKC). We also determined the gene expression of insulin; pancreas duodenum homeobox 1; and endoplasmic reticulum (ER) stress markers, such as Chop, ERp57, glucose-regulated protein 78/binding immunoglobulin protein, and inositol 1,4,5-triphosphate receptors. Ethanol reduced insulin secretion by interfering with muscarinic signaling and PKC activation but not the K-ATP channels. In addition, ethanol reduced insulin content and caused ER stress. The deleterious effects of ethanol on β-cells were prevented by 4-methyl pyrazole, an inhibitor of alcohol dehydrogenase, suggesting that ethanol metabolism is required for these effects.

Dose-related effects of red wine and alcohol on heart rate variability

In healthy subjects a standard drink of either red wine (RW) or ethanol (EtOH) has no effect on muscle sympathetic nerve activity or on heart rate (HR), whereas two drinks increase both. Using time- and frequency-domain indexes of HR variability (HRV), we now tested in 12 subjects (24-47 yr, 6 men) the hypotheses that 1) this HR increase reflects concurrent dose-related augmented sympathetic HR modulation and 2) RW with high-polyphenol content differs from EtOH in its acute HRV effects. RW, EtOH, and water were provided on 3 days, 2 wk apart according to a randomized, single-blind design. Eight-minute segments were analyzed. One alcoholic drink increased blood concentrations to 36 + or - 2 mg/dl (mean + or - SE), and 2 drinks to 72 + or - 4 (RW) and 80 + or - 2 mg/dl (EtOH). RW quadrupled plasma resveratrol (P < 0.001). HR fell after both water drinks. When compared with respective baselines, one alcoholic drink had no effect on HR or HRV, whereas two glasses of both increased HR (RW, +5.4 + or - 1.2; and EtOH, +5.7 + or - 1.2 min(-1); P < 0.001), decreased total HRV by 28-33% (P < 0.05) and high-frequency spectral power by 32-42% (vagal HR modulation), and increased low-frequency power by 28-34% and the ratio of low frequency to high frequency by 98-119% (sympathetic HR modulation) (all, P < or = 0.01). In summary, when compared with water, one standard drink lowered time- and frequency-domain markers of vagal HR modulation. When compared with respective baselines, two alcoholic drinks increased HR by diminished vagal and augmented sympathetic HR modulation. Thus alcohol exerts dose-dependent HRV responses, with RW and EtOH having a similar effect.

Alcohol consumption and diabetes risk in the Diabetes Prevention Program

BACKGROUND

Moderate alcohol consumption is associated with a decreased risk of type 2 diabetes in the general population, but little is known about the effects in individuals at high risk of diabetes.

OBJECTIVES

The objectives were to determine associations between alcohol consumption and diabetes risk factors and whether alcohol consumption was a predictor of incident diabetes in individuals enrolled in the Diabetes Prevention Program (DPP).

DESIGN

DPP participants (n = 3175) had impaired glucose tolerance (2-h glucose: 7.8-11.1 mmol/L), elevated fasting glucose (5.3-7.0 mmol/L), and a body mass index (in kg/m(2)) > or =24. Participants were randomly assigned to placebo, metformin, or lifestyle modification and were followed for a mean of 3.2 y. Alcohol intake was assessed at baseline and year 1 by using a semiquantitative food-frequency questionnaire. Diabetes was diagnosed by annual oral-glucose-tolerance testing and semiannual fasting plasma glucose measurement.

RESULTS

Participants who reported higher alcohol consumption tended to be male, older, white, and less obese and to have a higher calorie intake and a higher HDL-cholesterol concentration. Higher alcohol consumption was associated with lower insulin secretion at any level of insulin sensitivity. We found lower incidence rates of diabetes with higher alcohol consumption in the metformin (P < 0.01 for trend) and lifestyle modification (P = 0.02 for trend) groups, which remained significant after adjustment for multiple baseline covariates. No similar association was observed in the placebo group.

CONCLUSIONS

Despite overall low rates of alcohol consumption, there was a reduced risk of incident diabetes in those who reported modest daily alcohol intake and were assigned to metformin or lifestyle modification. Moderate daily alcohol intake is associated with lower insulin secretion-an effect that warrants further investigation. This trial was registered at clinicaltrials.gov as NCT00038727.

Insulin resistance in experimental alcohol-induced liver disease

BACKGROUND AND AIM

Chronic ethanol consumption impairs liver regeneration due, in part, to inhibition of insulin signaling. This study characterizes the mechanisms and consequences of ethanol-impaired insulin signaling in relation to oxidative injury and altered gene expression.

METHODS

Long-Evans rats were fed for 8 weeks with isocaloric liquid diets containing 0% (control) or 37% ethanol (caloric content). Livers were used to examine histopathology, indices of oxidative stress, gene expression required for insulin and insulin-like growth factor (IGF) signaling, insulin-responsive gene expression, i.e. glyceraldehydes-3-phosphate dehydrogenase (GAPDH) and aspartyl-asparaginyl-beta-hydroxylase (AAH), and competitive equilibrium binding to the insulin, IGF-I, and IGF-II receptors.

RESULTS

Chronic ethanol exposure caused liver injury with increased hepatocellular steatosis, inflammation, apoptosis, and increased immunoreactivity for activated caspase-3, 8-hydroxy-2'-deoxyguanosine, and 4-hydroxy-2,3-nonenol. These effects were associated with increased expression of IGF-I receptor, IGF-II, and IGF-II receptor, and expression of IGF-I, AAH, and GAPDH, which mediate energy metabolism and cell motility/remodeling, and reduced binding to the insulin receptor.

CONCLUSIONS

Chronic ethanol-induced liver injury causes insulin resistance with inhibition of insulin-responsive genes needed for metabolism, remodeling, and regeneration. In contrast, the IGF-I and IGF-II signaling mechanisms remain relatively preserved, suggesting that insulin-regulated hepatic functions may be selectively vulnerable to the toxic effects of ethanol.

RETRACTED: Cardiac overexpression of alcohol dehydrogenase exacerbates chronic ethanol ingestion-induced myocardial dysfunction and hypertrophy: role of insulin signaling and ER stress

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). At the request of the University of Wyoming, this article has been retracted. The University of Wyoming's institutional investigation of the work authored by Dr. Jun Ren found evidence of data irregularities in Figures 2, 3 and 4 that affect the reported results and conclusions. All authors have been notified of the retraction of this article.

The cardioprotective effects of alcohol consumption: does cardiac autonomic function play a role?

Moderate alcohol consumption has cardioprotective properties and several mechanisms have been proposed. In over 4,000 men and women from the Whitehall II study, mean heart rate variability levels were lowest among those consuming the most alcohol per week, but in multivariate analyses no statistical associations were found. The cardiac autonomic nervous system is unlikely to explain much of the cardioprotective properties of alcohol.

Alcohol intake, insulin resistance, and abdominal obesity in elderly men

OBJECTIVE

Moderate and high alcohol intake have been associated with decreased and increased risk of type 2 diabetes, respectively. Insulin resistance, insulin secretion, and abdominal obesity are major predictors of diabetes, but the links with alcohol intake remain contradictory because of limited data.

RESEARCH METHODS AND PROCEDURES

In a population-based cohort of 807 men (age, 70 years), we studied whether alcohol intake was related to insulin sensitivity, measured with the gold standard technique (euglycemic clamp), insulin secretion (early insulin response), or adiposity [BMI, waist circumference (WC), waist-to-hip ratio]. Alcohol intake was self-reported (questionnaire) and was assessed from a validated 7-day dietary record. The cross-sectional associations were evaluated using multivariable linear regression, adjusting for smoking, education level, physical activity, dietary total energy intake, hypertension, diabetes, triglycerides, and cholesterol.

RESULTS

In multivariable models, self-estimated alcohol intake was not related to insulin sensitivity, early insulin response, or BMI, but was positively related to WC (beta-coefficient, 0.77; 95% confidence interval, 0.15 to 1.39; p=0.02) and waist-to-hip ratio (0.006 [0.002-0.009], p=0.003). The association with WC and waist-to-hip ratio was most pronounced in men in the lowest tertile of BMI. The results using dietary records were similar.

DISCUSSION

Evaluated in a large sample in elderly men, neither insulin sensitivity measured by clamp technique nor insulin secretion was significantly associated with alcohol intake. However, high alcohol intake was associated with abdominal obesity, which might explain the higher diabetes risk previously observed in high alcohol consumers.

Alcohol-induced disruption of endocrine signaling

This article contains the proceedings of a symposium at the 2006 ISBRA meeting in Sydney Australia, organized and cochaired by Martin J. Ronis and Thomas M. Badger. The presentations were (1) Effect of long-term ethanol consumption on liver injury and repair, by Jack R. Wands; (2) Alcohol-induced insulin resistance in liver: potential roles in regulation of ADH expression, ethanol clearance, and alcoholic liver disease, by Thomas M. Badger; (3) Chronic gestational exposure to ethanol causes brain insulin and insulin-like growth factor resistance, by Suzanne M de la Monte; (4) Disruption of IGF-1 signaling in muscle: a mechanism underlying alcoholic myopathy, by Charles H. Lang; (5) The role of reduced plasma estradiol and impaired estrogen signaling in alcohol-induced bone loss, by Martin J. Ronis; and (6) Short-term influence of alcohol on appetite-regulating hormones in man, by Jan Calissendorff.

Brewing controversies: Darwinian perspective on the adaptive and maladaptive effects of caffeine and ethanol as dietary autonomic modulators

Ethanol and caffeine are two of the oldest human drugs. Their pervasive integration into the modern human diet may reflect behavioral attempts to correct maladaptations induced by evolutionary displacement of the autonomic system. The dietary adoption of caffeine may parallel the emergence of cognition as an independent basis of competition. Enhancement of the cognitive ability to gather and process information likely evolved as a valuable adjunct to physical behavior in prehistoric fight-or-flight encounters. Caffeine effectively exploits this pre-existing association between adrenergic activity and cognitive readiness, leading to its use in the modern environment where success in competition increasingly depends on cognitive, rather than physical, prowess. Ethanol may have emerged as a dietary means to buffer the maladaptive chronic sympathetic activation and fear response associated with stressful lifestyles and the social phobias associated with the dissolution of kin networks. We explore the health implications of ethanol and caffeine use, with particular attention to their acute and chronic effects on the autonomic axis. The putative protective effects of ethanol in surviving major trauma or reducing inflammation and heart disease may relate to tempering the behavioral and cardiovascular consequences of catastrophic or chronic sympathetic activation. Acute or chronic abuse of ethanol manifests paradoxical pro-adrenergic effects such as tremors and insomnia that may partly represent compensatory responses. Compensatory remodeling may also explain why confirmation of detrimental effects related to caffeine-induced sympathetic activation has proven elusive; indeed, paradoxical pro-vagal benefits may eventually be recognized. Ethanol and caffeine are potential agents that may beneficially expand the dynamic range of the autonomic system. In an environment where the Darwinian value of knowledge has increasingly supplanted that of physical traits, the consumption of caffeine and alcohol may represent both a cause and an effect of modern human evolution.

Chronic alcohol consumption alters mammalian target of rapamycin (mTOR), reduces ribosomal p70s6 kinase and p4E-BP1 levels in mouse cerebral cortex

Reduced insulin sensitivity following chronic alcohol consumption may contribute to alcohol-induced brain damage although the underlying mechanism(s) has not been elucidated. This study was designed to examine the effect of chronic alcohol intake on insulin signaling in mouse cerebral cortex. FVB mice were fed with a 4% alcohol diet for 16 weeks. Insulin receptor substrates (IRS-1, IRS-2) and post-receptor signaling molecules Akt, mammalian target of rapamycin (mTOR), ribosomal p70s6 kinase (p70s6k) and the eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) as well as the apoptotic marker caspase-3 were evaluated using Western blot analysis. Chronic alcohol intake significantly dampened whole body glucose tolerance, enhanced expression of caspase-3 and mTOR, reduced p70s6k and 4E-BP1 with little effect on Akt signaling in alcohol-consuming mice. These data suggest that chronic alcohol intake may contribute to cerebral cortex dysfunction through mechanisms related, at least in part, to dampened post insulin receptor signaling at the levels of mTOR, p70s6k and 4E-BP1.

The many metrics of cardiac chronotropy: a pragmatic primer and a brief comparison of metrics

This paper focuses on pragmatic issues in obtaining measures of cardiac vagal control, and overviews a set of freely available software tools for obtaining several widely used metrics that putatively reflect sympathetic and/or parasympathetic contributions to cardiac chronotropy. After an overview of those metrics, and a discussion of potential confounds and extraneous influences, an empirical examination of the relationships amongst these metrics is provided. This study examined 10 metrics in 96 unselected college students under conditions of resting baseline and serial paced arithmetic. Intercorrelations between metrics were very high. Factor analyses were conducted on the metrics reflecting variability in cardiac rate, once at baseline and again during mental arithmetic. Factor structure was highly stable across tasks, and included a factor that had high loadings of all variables except Toichi's "cardiac sympathetic index" (CSI), and a second factor that was defined predominantly by the CSI. Although generally highly correlated, the various metrics responded differently under challenge.

CARDIAC OVEREXPRESSION OF METALLOTHIONEIN RESCUES CHRONIC ALCOHOL INTAKE-INDUCED CARDIOMYOCYTE DYSFUNCTION: ROLE OF AKT, MAMMALIAN TARGET OF RAPAMYCIN AND RIBOSOMAL P70S6 KINASE

AIMS

Reduced insulin sensitivity following alcohol intake plays a role in alcohol-induced organ damage although its precise mechanism is undefined. This study was designed to examine the effect of cardiac overexpression of the antioxidant metallothionein on alcohol-induced cardiac contractile dysfunction and post-receptor insulin signaling.

METHODS

FVB and metallothionein mice were fed a 4% alcohol diet for 16 weeks. Cardiomyocyte contractile function was evaluated including peak shortening (PS), time-to-PS (TPS), and time-to-relengthening (TR(90)). Post-insulin receptor signaling molecules Akt, mammalian target of rapamycin (mTOR), and ribosomal p70s6 kinase (p70s6k) were evaluated using western blot analysis. Akt1 kinase activity was assayed with a phosphotransferase kit.

RESULTS

Alcohol intake dampened whole body glucose tolerance, depressed PS, shortened TPS, and prolonged TR(90), which were abrogated by metallothionein with the exception of glucose intolerance. Our results revealed reduced expression of total Akt, phosphorylated mTOR, and phosphorylated p70s6k-to-p70s6k ratio as well as Akt1 kinase activity in alcohol consuming FVB mice. Phosphorylated Akt, total mTOR, and phosphorylated p70s6k were unaffected by alcohol. Metallothionein ablated reduced Akt protein and kinase activity without affecting any other proteins or their phosphorylation.

CONCLUSION

In summary, our data suggest that chronic alcohol intake interrupted cardiac contractile function and Akt/mTOR/p70s6k signaling. Akt but unlikely mTOR and p70s6k may contribute to metallothionein-elicited cardiac protective response.

The effect of acute, chronic, and prenatal ethanol exposure on insulin sensitivity

Ethanol has been considered as a lifestyle factor that may influence the risk of type 2 diabetes mellitus. In healthy adults, acute ethanol consumption results in insulin resistance. Acute ethanol consumption causes insulin resistance selectively in skeletal muscle by an indirect mechanism. Possible mediators include triglycerides (TGs), catecholamines, acetaldehyde, alterations in insulin binding, and hepatic insulin sensitizing substance (HISS). Recent studies in rats showed that acute administration of ethanol causes insulin resistance in a dose-dependent manner that is secondary to the blockade of insulin-induced HISS release. Chronic ethanol consumption may improve insulin sensitivity, but the results from the randomized controlled trials are mixed. Differences in ethanol dose, consumption period, and abstention period may account for the discrepant results. Epidemiological studies have suggested that the relationship between ethanol and insulin sensitivity is either an inverted U-shape or a positive linear relationship. Future randomized controlled trials should consider the dose of ethanol and the duration of ethanol consumption and abstention in the experimental design. Chronic prenatal and postnatal (nursing) ethanol exposure results in insulin resistance that is secondary to the absence of HISS release/action with the HISS-independent insulin action and insulin-like growth factor-1 (IGF-1)-mediated glucose disposal action remaining unimpaired. The impaired HISS release may be related to a reduction in hepatic glutathione (GSH) levels. The effect of chronic ethanol consumption on HISS has not been evaluated.

Relation of alcohol use and smoking to glucose tolerance status in Japanese men

To investigate the relation of alcohol use and cigarette smoking to glucose tolerance status, we performed a cross-sectional study of 3038 male officials aged 46-59 years in the Self-Defense Forces. Glucose tolerance status was determined by a 75-g oral glucose tolerance test. A self-administered questionnaire was used to ascertain alcohol use, smoking habits, and other lifestyle characteristics. Statistical adjustment was made for parental history of diabetes, body mass index, and leisure-time physical activity. Alcohol use was positively associated with impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes mellitus each. The association was dose-dependent, with odds of each category of glucose intolerance increased even among those with moderate alcohol use. Cigarette smoking was not related to any categories of glucose intolerance. Alcohol use may confer increased risks not only of type 2 diabetes mellitus but also of preceding glucose intolerance status. Smoking does not seem to deteriorate glucose tolerance.

Women living alone have an increased risk to develop diabetes, which is explained mainly by lifestyle factors

OBJECTIVE

The purpose of this study was to assess the role of household conditions for the progression to diabetes in women with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

A total of 461 women, aged 50-64 years, with IGT defined by an oral glucose tolerance test, had baseline advice on physical exercise, diet, smoking, and alcohol habits. Physical examination, blood tests, and questionnaires were completed at baseline and after 2.5 years. Household status was categorized into living alone or with a partner, other adults, or children.

RESULTS

Women living alone had a 2.68-fold increased risk (95% CI 1.02-7.05) of developing diabetes after adjustments for biological risk factors. Further stepwise adjustments for education, occupation, subjective mental health, exercise, diet, and alcohol showed remaining significant odds ratios (ORs), decreasing from 3.26 (1.19-8.96) to 3.03 (1.02-8.99). However, when smoking status was added, the OR became nonsignificant, 2.07 (0.62-6.88). More women who lived alone smoked and did not reduce their daily cigarette consumption compared with women in other household conditions. At follow-up, women living alone had reduced their alcohol consumption and were more often abstainers and fewer had healthy dietary habits or had improved their diet. Physical exercise did not differ among the groups. Separate analyses of any other household status did not show any excess risk for development of diabetes.

CONCLUSIONS

Women living alone had a higher risk to progress from IGT to diabetes, mostly explained by smoking, alcohol, and dietary habits. Household conditions should be accounted for when assessing future risk for diabetes.

Alcohol for the prevention of type 2 diabetes mellitus?

While diabetes mellitus is recognized clinically as a complication of alcohol dependence, in the last 15 years several large prospective studies have demonstrated a significant reduction in risk of incident type 2 diabetes in moderate drinkers. In this article, we review prospective studies on the association between alcohol consumption and incidence of diabetes. Few prospective studies have demonstrated an unequivocal positive association between alcohol use and incidence of diabetes. A number of large prospective studies have now demonstrated an inverse association: typically a 40% risk reduction after controlling for other major risk factors. Studies based on cohorts of health professionals have not demonstrated an increased risk of diabetes with heavier consumption, but these cohorts contain few heavy drinkers. Some cohorts drawn from the general population have shown a J- or U-shaped association between level of alcohol consumption and incidence of diabetes. Frequent moderate drinking has been reported to be associated with lower risk than infrequent drinking. There have been contradictory reports on the importance of the type of alcoholic beverage and whether the effect of alcohol differs according to the bodyweight of the drinker. We conclude that like many other chronic diseases, there is a delicate balance between the harmful and beneficial effects of alcohol on the incidence of diabetes. In moderate amounts, drinking is associated with a reduced risk of diabetes, whereas in higher amounts with an increased risk.

Primary prevention of diabetes: what can be done and how much can be prevented?

Although it is widely believed that type 2 diabetes mellitus is the result of a complex interplay between genetic and environmental factors, compelling evidence from epidemiologic studies indicates that the current worldwide diabetes epidemic is largely due to changes in diet and lifestyle. Prospective cohort studies and randomized clinical trials have demonstrated that type 2 diabetes can be prevented largely through moderate diet and lifestyle modifications. Excess adiposity is the most important risk factor for diabetes, and thus, maintaining a healthy body weight and avoiding weight gain during adulthood is the cornerstone of diabetes prevention. Increasing physical activity and reducing sedentary behaviors such as prolonged TV watching are important both for maintaining body weight and improving insulin sensitivity. There is increasing evidence that the quality of fat and carbohydrate plays a more important role than does the quantity, and thus, public health strategies should emphasize replacing saturated and trans fats with unsaturated fats and replacing refined grain products with whole grains. Recent studies have also suggested a potential role for coffee, dairy, nuts, magnesium, and calcium in preventing diabetes. Overall, a healthy diet, together with regular physical activity, maintenance of a healthy weight, moderate alcohol consumption, and avoidance of sedentary behaviors and smoking, could nearly eliminate type 2 diabetes. However, there is still a wide gap between what we know and what we practice in the field of public health; how to narrow that gap remains a major public health challenge.

Cardiovascular responses to physical and psychological stress in female alcoholics with transitory hypertension after early abstinence

BACKGROUND

Male alcoholic patients with acute withdrawal hypertension have shown exaggerated cardiovascular reactivity to stress after 3 to 4 weeks of abstinence, although resting blood pressures (BP) had returned to normal. Studies of this nature, however, have not been extended to women.

METHODS

In this study, 32 alcohol-dependent women, abstinent for 4 weeks, were compared with 16 healthy controls on cardiovascular hemodynamics during rest and in response to 2 moderately aversive stressors: isometric handgrip and a speech task. The alcoholics were placed according to withdrawal BP into transitory hypertensive (tHT; n = 16; BP >or=140/90 mm Hg) and normotensive (NT; n = 16; BP <140/90 mm Hg) subgroups.

RESULTS

During stress testing, the transitory hypertensive women had increased diastolic BP (p < 0.01), a higher peripheral resistance index (p < 0.05), and a reduced cardiac efficiency index (p < 0.03) relative to the normotensive and control subjects.

CONCLUSIONS

This cardiovascular pattern suggests that both cardiac and vascular functions were altered adversely in the transitory hypertensives. In contrast to men examined in previous studies, the transitory hypertensive women had no exaggeration of BP reactivity, but instead showed sustained alterations of resting cardiovascular function in relation to chronic alcohol consumption. Although the pattern of cardiovascular dysregulation seems to be different in female alcoholics than in males, it is consistent with studies showing that cardiovascular effects in women are more severe than in men and emerge at a lower threshold level of chronic drinking.

Alcohol consumption and insulin resistance syndrome parameters: associations and evolutions in a longitudinal analysis of the French DESIR cohort

PURPOSE

To determine the effects of average alcohol consumption and changes in alcohol intake on the insulin resistance syndrome parameters in a 3-year follow-up study.

METHODS

Longitudinal study of 1856 and 1529 alcohol drinking men and women in the French DESIR study (Data from an Epidemiological Study on the Insulin Resistance syndrome), aged 30 to 64 years.

RESULTS

In men, fasting glucose, body mass index, waist circumference, systolic blood pressure, and HDL-cholesterol were positively associated with average alcohol consumption while there was no association with insulin or triglycerides concentrations. A change in alcohol intake was positively associated with HDL-cholesterol concentration and systolic blood pressure at follow-up. These effects of alcohol could not be attributed specifically to the intake of wine. In women, while the alcohol HDL-cholesterol relation was similar to that found in the men, the only significant effect of average alcohol intake was an increase in systolic blood pressure, with a spurious decrease in blood pressure related to a 3-year increase in alcohol intake.

CONCLUSIONS

Alcohol only provided a beneficial effect on HDL-cholesterol. The beneficial effect seen by other authors of moderate alcohol drinking on diabetes and cardiovascular risk may be due to effects on parameters other than those included in the current definitions of the insulin resistance syndrome.

Effect of moderate alcohol consumption on adiponectin, tumor necrosis factor-alpha, and insulin sensitivity

OBJECTIVE

Epidemiological studies suggest that moderate alcohol consumers have enhanced insulin sensitivity and a reduced risk of type 2 diabetes. Adiponectin, an adipocyte-derived plasma protein, has been found to be negatively associated with adiposity and positively associated with insulin sensitivity. Moderate alcohol consumption may increase adiponectin, which in turn causes a decrease of tumor necrosis factor (TNF)-alpha. A decreased TNF-alpha level may consequently increase insulin sensitivity.

RESEARCH DESIGN AND METHODS

To test this hypothesis, we performed a randomized crossover partially diet-controlled study. A total of 23 healthy middle-aged male subjects consumed daily four glasses of whisky (40 g ethanol) or tap water with dinner during two successive periods of 17 days.

RESULTS

Moderate alcohol consumption increased plasma adiponectin level (11%; P = 0.0002) but did not affect plasma TNF-alpha level. An increase in insulin sensitivity index was observed in an insulin-resistant subgroup (21%; P = 0.11), which positively correlated with the relative alcohol-induced increase in plasma adiponectin level (r = 0.73, P = 0.02).

CONCLUSIONS

The experimental results are in agreement with observational data. Moderate alcohol consumption improved insulin sensitivity in relatively insulin-resistant middle-aged men, an effect that may be mediated through alcohol-induced increases in adiponectin.

Moderate alcohol consumption, estrogen replacement therapy, and physical activity are associated with increased insulin sensitivity: is abdominal adiposity the mediator?

OBJECTIVE

To investigate 1). associations between environmental factors (alcohol consumption, hormone replacement therapy [HRT], and physical activity) and insulin resistance and secretion, independent of genetic influences; 2). the contribution of abdominal adiposity to these relationships; and 3). whether gene-environment interactions mediate these associations.

RESEARCH DESIGN AND METHODS

Reported effects of lifestyle factors on insulin resistance and secretion are inconsistent, possibly due to difficulty in dissecting environmental from genetic influences and to confounding by adiposity. We examined these relationships in 798 nondiabetic female twins. Insulin resistance and secretion were estimated by modified homeostasis model assessment (HOMA-R' and HOMA-beta', respectively). Percent total body fat and percent central abdominal fat (CAF) were measured by dual-energy X-ray absorptiometry.

RESULTS

All categories of alcohol consumption were associated with lower insulin levels and HOMA-beta' than abstinence. Only moderate alcohol consumers (11-20 units/week) had lower HOMA-R' than abstainers (-0.16 +/- 0.09 vs. 0.14 +/- 0.13 SD, P = 0.048). This difference was attenuated after controlling for percent CAF (P = 0.57), which was lower in moderate drinkers. Controlling for genetic and smoking effects in cotwin case-control analysis, monozygotic pairs discordant for alcohol consumption had greater within-pair differences in HOMA-R' than concordant pairs (P = 0.02). Postmenopausal women using estrogen-only HRT had lower HOMA-R' than non-HRT users (-0.33 +/- 0.16 vs. 0.17 +/- 0.08 SD, P = 0.003), even after controlling for percent CAF. Lower fasting glucose levels and insulin resistance and secretion indexes in physically active subjects were partly explained by lower abdominal adiposity.

CONCLUSIONS

Moderate alcohol consumption, estrogen replacement, and physical activity are associated with increased insulin sensitivity in female twins. The favorable effects of moderate alcohol consumption and physical activity on insulin sensitivity are partly mediated by lower abdominal adiposity.

The effect of alcohol intake on insulin sensitivity in men: a randomized controlled trial

OBJECTIVE

Population data suggest that alcohol consumption may influence the risk of diabetes in a biphasic manner, but this has not been tested by any controlled interventions. The object of this study was to determine whether reducing alcohol intake in moderate-to-heavy drinkers (40-110 g/day) results in improvement in insulin sensitivity.

RESEARCH DESIGN AND METHODS

A 4-week run-in period where subjects maintained their usual drinking pattern was followed by randomization to a two-way cross-over intervention study. In each of two 4-week treatment interventions, subjects either substituted their usual alcohol intake with a 0.9% alcohol beer or maintained their usual alcohol intake. At the end of each 4-week period, insulin sensitivity as determined by the low-dose insulin glucose infusion test and the homeostasis model assessment (HOMA) score, and biomarkers of alcohol consumption (gamma-glutamyl transpeptidase [gamma-GT] and HDL cholesterol) were measured.

RESULTS

A total of 16 healthy men aged 51.0 +/- 2.7 (mean +/- SEM) years with a BMI of 26.4 +/- 0.61 kg/m(2) completed the study. There was a large reduction in alcohol intake (72.4 +/- 5.0 vs. 7.9 +/- 1.6 g/day, P < 0.001) and significant reductions in gamma-GT (geometric mean 24.4 units/l [95% CI 19.7-30.2] vs. 18.6 units/l [15.5-22.2], P < 0.01) and HDL cholesterol (1.36 +/- 0.07 vs. 1.13 +/- 0.07 mmol/l, P < 0.001). There was no effect of alcohol on insulin sensitivity index (ISI), fasting insulin, glucose, or HOMA score.

CONCLUSIONS

A substantial reduction in alcohol intake from 7.2 to 0.8 standard drinks per day in healthy men did not change insulin sensitivity as measured by ISI or HOMA score.