Application of bioelectric impedance methodology and prediction equations to determine the volume of distribution for ethanol

The impact of total body water on breath alcohol calculations

Due to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h⁻¹) and women (0.074 ± 0.017 mg/L h⁻¹). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).

Body shape and composition in HIV-infected women: an urban cohort

OBJECTIVES

Alterations in body shape and composition are associated with HIV/AIDS. Wasting remains prevalent; increasingly, lipodystrophy is reported. Obesity is also epidemic in the USA. In this study, we sought to characterize the body changes reported by women attending a US urban clinic, and to evaluate contributing factors using inexpensive methods that are readily available in clinical practice.

METHODS

In an urban Maryland clinic, a cross-section of HIV-infected women were evaluated by self report, anthropomorphic measurements, bioelectric impedance analysis (BIA) and chart review; they were categorized as no change, lipodystrophy, weight loss/wasting or weight gain/obesity.

RESULTS

One hundred and sixty-one women were evaluated: 144 (89%) were African-American; 100 (62%) had used intravenous drugs and 40 (25%) were actively injecting drugs, while 39 (24%) smoked crack. Ninety-five (59%) were on highly active antiretroviral therapy (HAART) for a median period of 11.7 months [interquartile range (IQR)=4.5-24.2]. Since starting current HAART or in the previous year, 12 (7.4%) reported lipodystrophy changes, 85 (52.8%) weight gain, 27 (16.8%) overall weight loss, and 37 (23.0%) no change. Lipodystrophy was associated with higher CD4 percentage (P=0.03), lower frequency of crack use (P=0.04) and higher educational level (P=0.03). Weight loss correlated with longer duration of infection (P=0.01), select BIA results and increased rate of crack use (P=0.005). Weight gain was associated with higher fat mass (P=0.005), higher peak viral load (P=0.02), and lower rate of intravenous drug use (P=0.03).

CONCLUSIONS

Self-reported changes in body shape were common. Obesity and complications of illicit drug use were more prevalent than lipodystrophy in this inner-city population of HIV-positive women.

Nutritional status and body fluid distribution in chronic alcoholics compared with controls

BACKGROUND

At present few data are available on the total body water (TBW) content and in particular on the distribution of water in the intra- and extracellular compartments (ICW and ECW) of alcoholics. The aim of this study was to evaluate TBW, ICW, and ECW in chronic alcoholic patients.

METHODS

Thirty-six alcoholics meeting DSM-III-R criteria for diagnosis (20 men, 16 women; body mass index [BMI] 22.3+/-2.57 kg/m2) were enrolled. Fifty-four healthy social drinkers (31 men, 23 women; BMI 23.7+/-1.68 kg/m2) matched for age and height were used as controls. Systolic and diastolic blood pressure was measured for all cases. All patients were assessed using specific anthropometric measurements. The waist-to-hip ratio (WHR) was used as an indicator of body fat distribution. TBW was measured by isotopic dilution by giving 100 microCi of tritiated water. ICW and ECW were assessed by multifrequence bioelectric impedance analysis (BIA). Basal metabolic rate (BMR) was measured by indirect calorimetry.

RESULTS

Body weight was lower in the alcoholics than in the controls (61.9+/-5.5 kg vs. 65.8+/-5.2 kg;p < 0.01), essentially due to a reduction in fat mass. Significantly higher WHR values were found in both male (p < 0.001) and female (p < 0.001) alcoholics than in healthy subjects. A higher ECW/TBW ratio was found in the alcoholics compared with the controls, both as a whole (0.53+/-0.04 vs. 0.41+/-0.03; p < 0.0001) and separated by gender (p < 0.001).

CONCLUSIONS

The increased ECW could derive from an increase in cellular permeability related to endothelial damage linked to the vasoconstriction present in the alcoholics and/or to a direct toxic effect of ethanol on cellular membranes. In addition, because the high ECW volumes correlated positively with WHR in the alcoholics, a potential association of these two factors in determining an increased risk of liver disease, hypertension, and cardiovascular disease may exist. Finally, the lower TBW characteristic of women may be one of the reasons for the observed greater rate of toxic effects of ethanol that occur in women.

Residual pressor effects of chronic alcohol in detoxified alcoholics

Although research in population studies has indicated that recent alcohol intake is positively correlated with blood pressure, there is a need to study the relationship of blood pressure to measures of lifetime alcohol intake in alcoholics. To this end, we assessed systolic and diastolic pressures and lifetime alcohol intake through structured interviews with 253 normotensive recovering alcoholics. Blood pressures were first corrected with multiple linear regression for the influence of confounding or modifying variables and then were regressed against alcohol consumption measures. Systolic pressure was significantly correlated (positively) with only a few measures of recent alcohol intake, and the correlations were not high (r2 = .05 to .11, P < .05). Diastolic pressure was found to be highly and positively correlated with the duration of the drinking career, but more so in blacks than in whites. The total lifetime dose of alcohol was found to be positively correlated with diastolic but not systolic pressure, but only in black male alcoholics. The steeper slope of the regression of blood pressure versus lifetime total alcohol or duration of the drinking career in black alcoholics suggests greater cardiovascular susceptibility to alcohol toxicity as lifetime doses increase and as the drinking career lengthens.