Effects of Alcohol Consumption on Hepatocellular Injury in Japanese Men

Risk assessment of low-dose ethanol in food

A high variety of food contains low doses of ethanol which are sometimes difficult to identify by consumers (adults or children). However, even low doses of ethanol intake raises several toxicological concerns. In the present study, an enzymatic assay and an HS-GC/MS procedure were applied to determine the ethanol levels of 1260 samples from different food categories covering "nonalcoholic" beer, fruit juices/drinks, baked goods, bananas and baby foods. Based on these results, ethanol levels resulting from acute or chronic ethanol intake was calculated using consumption data from the EFSA Comprehensive European Food Consumption Database. Thus, health-based guidance values (HBGV) for ethanol intake were derived for acute or chronic exposure based on the available literature. For acute exposure, very few samples resulted in concerning ethanol uptake levels but following chronic exposure the here derived HBGV level was exceeded in several cases. This is mainly due to the following reasons: (1) certain amounts of ethanol are still tolerated in "nonalcoholic" beer and (2) presence of endogenous produced ethanol in bananas or baked goods via fermentation. Most analysed food samples, however, do not result in elevated ethanol doses linked with a potentially high risk following acute and chronic consumption by adults and children.

Can resveratrol in wine protect against the carcinogenicity of ethanol? A probabilistic dose-response assessment

Resveratrol, which may occur in wine, was suggested to act as a chemopreventive agent against the carcinogenic effects of ethanol. The assumption was based on data from experimental animals, which have shown that resveratrol above certain thresholds may reduce the incidence of tumours in several of the alcohol-related cancer sites (colon, liver and female breast). Using a probabilistic Monte Carlo type methodology, we estimated daily intake based on chemical analysis of resveratrol (n = 672) and ethanol (n = 867). Benchmark dose (BMD)-response modelling was conducted for resveratrol based on eight animal experiments, whereas BMD data for ethanol were taken from the literature. The margin of exposure (MOE) was calculated for both substances as an indicator if the intake may reach effective dosages. For intake of one 100-mL glass of wine, the average MOE was found to be 4.1 for ethanol and 459,937 for resveratrol. In the best-case scenario for resveratrol (e.g., very high contents and assuming a low effective dosage), the minimum MOE would be 111, which means that 111 glasses of wine need to be consumed daily to reach the BMD. The MOE ratio between resveratrol and ethanol is 166,128 on average, meaning that per glass of wine, ethanol is more than 100,000 times more potent than resveratrol. As resveratrol intake may not optimally reach the effective dosage, our study excludes a preventive effect of this substance on alcohol-related cancer. Commercial information about cancer-preventive or -protective effects of resveratrol in wine is misleading and must be prohibited.

Variation in benchmark dose (BMD) and the 95% lower confidence limit of benchmark dose (BMDL) among general Japanese populations with no anthropogenic exposure to cadmium

BACKGROUND

The use of benchmark dose (BMD) and the 95% lower confidence limit of benchmark dose (BMDL) have been gaining popularity not only in experimental studies but also in epidemiological studies including those on toxicology of cadmium (Cd), a ubiquitous hazardous element in the environment. However, the reproducibility of BMD and BMDL values has seldom been examined.

OBJECTIVES

This study was initiated to determine whether consistent BMD and BMDL values are obtained for similar non-exposed populations, i.e., the populations with no anthropogenic exposure to Cd in a single nation of Japan.

METHODS

Cd (an exposure marker), α(1)-microglobulin (α(1)-MG), β(2)-microglobulin (β(2)-MG) and N-acetyl-β-D-glucosaminidase (NAG) (three effect markers of tubular dysfunction) levels in the urine of adult Japanese women from five previous publications of this study group were examined. Overall, data were available for 17,375 cases (in 16 prefectures) regarding Cd, α(1)-MG and β(2)-MG, and 6,409 cases (in ten prefectures) regarding NAG. The data were used to calculate BMD and BMDL values taking advantage of the hybrid approach (Budtz-Jǿrgensen et al. in Biometrics 57:698-706, 2001). It was possible to calculate BMD and BMDL values for α(1)-MG and β(2)-MG for all of the 16 prefectures with 17,375 cases, whereas the values for NAG were successfully calculated for nine prefectures with 5,843 cases.

RESULTS

The application gave BMD values of 1.92, 2.46 and 2.32 μg Cd/g cr for α(1)-MG, β(2)-MG and NAG, respectively, and BMDL values of 1.83, 2.32 and 2.09 μg Cd/g cr. Large inter-prefectural variations were observed in the BMD and BMDL; there was about fourfold difference both in BMD and in BMDL calculated for α(1)-MG and β(2)-MG in 16 prefectures, and the variation was greater (i.e., by about sevenfold) in BMD and BMDL for NAG in nine prefectures. A survey of relevant literature revealed variation in BMD and BMDL values of similar folds as observed in the present analyses in five studies of Japanese populations. Multiple regression analyses taking BMD or BMDL as a dependent variable and age, CR concentration and Cd concentration as independent variables showed both BMD and BMDL were significantly influenced by Cd concentration in cases of α(1)-MG and β(2)-MG, whereas BMD and BMDL for NAG was by CR.

CONCLUSIONS

Even when the analysis was conducted in a single nation, both BMD and BMDL for the Cd effect markers varied by ca. fourfold when examining α(1)-MG or β(2)-MG and the values varied by ca. sevenfold for NAG among Cd-non-exposed populations. The most influential factors in the study population may include urine density and Cd levels in the urine.

[Application of the benchmark dose approach to epidemiological endpoints with clinical standards]

OBJECTIVE

By publishing the scientific opinion entitled "Use of the benchmark dose (BMD) approach in risk assessment: Guidance of the Scientific Committee," the European Food Safety Authority (EFSA) recommended that the BMD approach, as an alternative to the traditionally used no-observed-adverse-effect level approach, be used as the method of choice for the determination of the reference point for deriving health-based guidance values and margins of exposure, and described the BMD approach as being extensively applicable to all chemicals, even to dose-effect assessment of epidemiological data. When the BMD approach was first proposed, the approach was expected to estimate the dose causing a low but measurable target organ effect. We examined whether the BMD approach can be applied to epidemiological endpoints with clinical standards.

METHODS

Comparisons between the BMD approach recommended by the EFSA and classical BMD approach (hybrid method) were conducted using epidemiological data with clinical standards.

RESULTS

The 95% lower confidence limit of the EFSA-based BMD tended to be considerably lower than that of the hybrid method. The former approach is easily applicable to dose-response data in published papers, though it is difficult to adjust for possible confounders. The cutoff values, calculated by the hybrid method, of epidemiological endpoints are nearly concordant with the clinical standards.

CONCLUSIONS

By using the BMD approach recommended by the EFSA, human health safety may be better guaranteed because of the lower reference points for hazardous substances. However, its application to epidemiological data does not always reflect toxicological implications in light of the clinical standard.

Epidemiology-based risk assessment using the benchmark dose/margin of exposure approach: the example of ethanol and liver cirrhosis

BACKGROUND

A novel approach to derive a threshold dose with respect to alcohol-related harm, the benchmark dose (BMD) methodology, is introduced to provide a basis for evidence-based drinking guidelines. This study is the first to calculate a BMD for alcohol exposure using epidemiological cohort data. With this BMD we will be able to calculate the margin of exposure (MOE) for alcohol consumption, which can be used for comparative risk assessment and applied to setting public health policy.

METHODS

Benchmark dose-response modelling of epidemiological data gathered during a recent systematic review and meta-analysis of alcohol consumption as a risk factor for liver cirrhosis morbidity and mortality.

RESULTS

For a benchmark response (BMR) of 1.5%, the resulting BMD values were 30.9 g/day for males and 29.7 g/day for females; the corresponding lower one-sided confidence values were 25.7 and 27.2 g/day, respectively. The intake scenario for the Canadian population resulted in an MOE of 1.23. Intake scenarios for individuals as based on the Canadian drinking guidelines led to MOE values between 0.96 and 1.91. Using an uncertainty factor of 10, the acceptable daily intake for alcohol would be 2.6 g/day.

CONCLUSIONS

The BMD approach was feasible in developing evidence-based guidelines for low-risk drinking. As our calculated MOEs result around unity (i.e. 1) for moderate drinking, it is evident that the current guidelines correspond very well to low risk on the dose-response curve. The BMD methodology therefore validates current guidelines. The results again highlight the health risk associated with alcohol consumption.

Estimation of benchmark dose as the threshold amount of alcohol consumption for blood pressure in Japanese workers

In order to determine the threshold amount of alcohol consumption for blood pressure, we calculated the benchmark dose (BMD) of alcohol consumption and its 95% lower confidence interval (BMDL) in Japanese workers. The subjects consisted of 4,383 males and 387 females in a Japanese steel company. The target variables were systolic, diastolic, and mean arterial pressures. The effects of other potential covariates such as age and body mass index were adjusted by including these covariates in the multiple linear regression models. In male workers, BMD/BMDL for alcohol consumption (g/week) at which the probability of an adverse response was estimated to increase by 5% relative to no alcohol consumption, were 396/315 (systolic blood pressure), 321/265 (diastolic blood pressure), and 326/269 (mean arterial pressures). These values were based on significant regression coefficients of alcohol consumption. In female workers, BMD/BMDL for alcohol consumption based on insignificant regression coefficients were 693/134 (systolic blood pressure), 199/90 (diastolic blood pressure), and 267/77 (mean arterial pressure). Therefore, BMDs/BMDLs in males were more informative than those in females as there was no significant relationship between alcohol and blood pressure in females. The threshold amount of alcohol consumption determined in this study provides valuable information for preventing alcohol-induced hypertension.

Clotted blood as sign of alcohol intoxication: a retrospective study

A total of 138 autopsies performed at the Institute of Legal Medicine of the University of Münster between 1994 and 2006 were subdivided into two groups: (1) 69 asphyxial deaths with a blood alcohol level (BAL) > 1 per thousand and (2) 69 asphyxial deaths with a BAL of 0.00 per thousand. The coagulation state in the central vessels was registered in all cases as fluid, compactly clotted or loosely clotted, and the post-mortem interval was recorded. Histology investigations were performed on the liver to analyze the incidence of hepatic fibrosis/cirrhosis. Fisher's exact test was performed to check for statistical significance. The blood was found to be clotted in 49.3% of the cases of group (1) and in 5.8% of group (2) (p < 0.01). The post-mortem interval did not have any influence on the coagulation state as observed in both groups. Liver fibrosis/cirrhosis was a rare finding detected in three cases in group 1 and in two cases in the control group 2 and, therefore, not relative to our observations. A distinctly positive BAL is often associated with heavy stages of blood coagulation as observed during autopsy. Distinctly positive alcohol concentrations have an influence on the fibrinolytic process and, hence, on the coagulation status.

Relation between benchmark dose and no-observed-adverse-effect level in clinical research: effects of daily alcohol intake on blood pressure in Japanese salesmen

The benchmark dose (BMD) is defined as the dose that corresponds to a specific change in an adverse response compared to the response in unexposed subjects, and the lower 95% confidence limit is termed the benchmark dose level (BMDL). In this study, the threshold of daily ethanol intake affecting blood pressure was calculated by both the BMD approach and multiple logistic regression analysis to clarify the relation between the BMDL and no-observed-adverse-effect level (NOAEL). Systolic and diastolic blood pressures (SBP and DBP) and daily ethanol intake were explored in 1,100 Japanese salesmen. The SBP and DBP were positively related to daily ethanol intake (p < 0.001) when adjusting for possible confounders such as age, body mass index, and smoking status. The adjusted risk for hypertension (SBP >or= 140 mmHg or DBP >or= 90 mmHg) increased significantly when daily ethanol intake exceeded 60 g/day, and the categorical dose of interest was 60.1-90 g/day. The BMDL and BMD of ethanol intake for increased SBP and DBP were estimated to be approximately 60 and 75 g/day, respectively. These findings suggest that the BMDL and BMD correspond to the NOAEL and lowest-observed-adverse-effect level, respectively, if the sample number of clinical data is large enough to confirm the dose-response association.

Critical dose of lead affecting postural balance in workers

BACKGROUND

The threshold blood lead (BPb) level for nervous system dysfunction in adults has been estimated to be 30-40 microg/dl. This study was carried out to estimate the critical dose of lead affecting the neuromotor function in workers by introducing the benchmark dose (BMD) approach, as well as to identify the specific postural sway to lead exposure.

METHODS

Postural sway parameters with spectral analysis were compared between 121 lead workers with BPb levels of 6-89 (mean 40) microg/dl and 60 unexposed controls.

RESULTS

All sway parameters, except for sagittal sways with eyes open, were significantly larger in the lead workers than in the controls; also, the Romberg quotient for sagittal sway was significantly higher in the lead workers. The BPb level in the lead workers was significantly related to sagittal sways at 1-2 Hz and 2-4 Hz with eyes open, and sagittal and transversal sways at 1-2 Hz and 2-4 Hz with eyes closed. The BMD levels of BPb (i.e., lower 95% confidence limits of BMD) were estimated to be 12.1-17.3 (mean 14.4) microg/dl for postural sway.

CONCLUSIONS

Neuromotor dysfunction in lead workers may be initiated at BPbs below the level previously accepted as effectless, and be characterized mainly by an increased sway of high frequency (1-4 Hz) in the sagittal direction with eyes closed (high Romberg quotient).

Cardiac autonomic imbalance in female nurses with shift work

The pathophysiology underlying the shift work-related cardiovascular disease is still poorly understood. The chronic effects of shift work on cardiac autonomic functions were assessed in 47 hospital nurses working under a rotating three-shift system (shift nurses) and 36 public health nurses without shift work (non-shift nurses). The heart rate variability, %LF and %HF (i.e., proportions of sympathetic and vagal activities, respectively), and LF/HF ratio were calculated from the electrocardiographic RR intervals by using autoregressive spectral analysis, and heart rate-corrected QT interval (QTc and QT index) was also measured. The LF/HF ratio, %LF, and QT index were significantly larger in the shift nurses than in the non-shift nurses; also, the power spectral density of HF (PSD(HF)) was significantly decreased in the shift nurses. There was a significant, inverse correlation between the corrected QT interval and PSD(HF) in the non-shift nurses, but not in the shift nurses. It is suggested that shift work in female nurses may cause a sympathodominant state due to depressed vagal tones. Also, a pathophysiology of shift work-related cardiovascular disease, derived from the present and previous findings, may be characterized by the attenuation of the inverse association between the corrected QT interval and vagal activity observed in non-shift workers.

Benchmark dose of lead inducing anemia at the workplace

To estimate the critical dose of lead inducing anemia in humans, the effects of lead on hemoglobin (Hb) and hematocrit (Hct) levels and red blood cell (RBC) count were examined in 388 male lead-exposed workers with blood lead (BPb) levels of 0.05-5.5 (mean 1.3) micromol/L by using the benchmark dose (BMD) approach. The BPb level was significantly related to Hb (regression coefficient beta=-0.276), RBC (beta=-11.35), and Hct (beta=-0.563) among the workers (p < 0.001) when controlling for age and working status. The average BPb levels were significantly higher in the workers with anemia (1.85 micromol/L), based on the WHO criteria, than in those without anemia (1.26 micromol/L). The benchmark dose levels of BPb (i.e., lower 95% confidence limits of BMD), calculated from the K-power model set at an abnormal probability of 5% in unexposed workers and an excess risk of 5% in exposed workers were estimated to be 0.94 micromol/L (19.5 microg/dl) for Hb, 0.94 micromol/L (19.4 microg/dl) for RBC, and 1.43 micromol/L (29.6 microg/dl) for Hct. These findings suggest that reduction in hematopoietic indicators may be initiated at BPbs below the level currently considered without effect.

Chronic heavy ethanol consumption is associated with decreased platelet aggregation in rats

Although moderate alcohol consumption seems to be protective against atherosclerosis, coronary artery disease rate increases with its higher doses. Platelet aggregation is an important process which contributes to the atherosclerosis. The aim of this study was to determine whether heavy ethanol consumption stimulates or inhibits platelet aggregation. Fourteen adult male Wistar rats were used. Ethanol (7.2%, v/v) in a modified liquid diet was given to eight rats for 21 days, which mimicked characteristics similar to human chronic alcoholism. Six rats constituted the control group. Adenosine diphophate (ADP) and collagen-induced platelet aggregation was measured in whole blood. We found reduced ADP-induced mean maximal aggregation in the alcoholic rat group compared to the control group at dose of 5 microM (p < 0.005). We also found decreased platelet aggregation responses to collagen in the alcoholic group (p < 0.006 for 2 microg/ml collagen, and p < 0.05 for 5 microg/ml collagen). In conclusion, chronic heavy ethanol consumption results in the decreased platelet aggregation in a rat model of alcoholism. Therefore, increased mortality from coronary artery disease in chronic alcoholism may be explained by other factors such as dietary imbalances and coexisting conditions, which include hypertension and depression.

Effects of Mixed Organic Solvents on Neuromotor Functions among Workers in Buddhist Altar Manufacturing Factories

To clarify the neuromotor effects of long-term exposure to mixed organic solvents, postural sway and tremor were measured in 62 solvent workers of four Buddhist altar manufacturing factories who had worked for 1-46 (mean 12) yr. By using the passive gas sampler, 8-h time-weighted average concentrations in the workers were estimated to be 0.02-8.7 ppm for toluene, 0.02-7.7 ppm for xylene, 0.02-5.5 ppm for styrene and 0.02-40.5 ppm for n-hexane. Sagittal sway and sway area of the posturography with eyes closed were significantly larger in the solvent workers than in 35 age-matched controls (p<0.05), and there was a significant difference in Romberg quotient of sagittal sway between the two groups (p<0.05). Also, tremor intensities at 1.0-5.9 Hz, 6.0-9.9 Hz and 10.0-13.9 Hz with the right hand, and at 6.0-9.9 Hz with the left hand were significantly stronger in the solvent workers than in the controls. Among the solvent workers, transversal and sagittal sways with eyes open and tremor intensity at 10.0-13.9 Hz were significantly related to toluene exposure (p<0.05), which may have been due to the acute effects of such solvents. These findings suggest that long-term exposure to mixed organic solvents may impair neuromotor functions as measured by postural sway and tremor.

Effects of shift work on autonomic and neuromotor functions in female nurses

Thirty-seven nurses with shift work, working under a rotating three-shift system, and 37 nurses without shift work, having worked during the daytime for one or more years prior to this study, were examined to assess the effects of shift work on cardiac autonomic and neuromotor functions. Their ages ranged from 25 to 58 yr. The electrocardiographic (ECG) R-R interval variability, %LF and %HF (i.e., proportions of sympathetic and parasympathetic activities, respectively), and LF/HF ratio were computed by means of autoregressive spectral and component analyses. The %LF and LF/HF ratio were significantly larger in the nurses with shift work than in those without shift work, although there was no significant difference in the heart rate-corrected QT interval on ECG between them. And, hand-ear coordination differed significantly between the nurses with shift work and those without. Despite the presence of potential selection bias, it is suggested that shift work in nurses may cause not only a long-term sympathodominant state but also some neuromotor impairment.