Carbohydrate deficient transferrin in alcoholic and non-alcoholic liver disease: a comparison of two assay methods

Obesity as a cause of "false-positive" alcohol misuse laboratory investigations

Three patients are reported with a prior history of alcohol misuse accompanied by abnormal liver toxicity tests and other indices of alcohol misuse. A decreased but persistently raised serum gamma-glutamyl transferase activity during subsequent abstinence or controlled drinking was interpreted incorrectly as due to continued alcohol misuse whereas obesity-related fatty liver was the probable cause. The value of serum carbohydrate deficient transferrin assays in the differential diagnosis of abnormal liver toxicity tests is emphasized.

Carbohydrate-deficient transferrin (CDT) determination by nephelometry using a commercial kit. Analytical and diagnostic aspects

Carbohydrate-deficient transferrin (CDT) has been proposed as the most efficient marker of alcohol abuse. Absolute and relative concentrations of CDT were measured with a commercial assay (%CDTTIA from AXIS-Shield, Oslo, Norway) using rate nephelometry for transferrin determination. One hundred eighty-eight alcoholic patients (154 males, 34 females) and 132 control patients (113 males, 19 females) were included in the study. Within-run and day-to-day imprecision were 3.15% and 9.77%, respectively. The calibration curve was stable for more than 4 months with a shift below 5%. The commercial assay lacked sensitivity (Se = 0.48), but was highly specific (Sp = 0.98). Lowering the cut-off from 6% to 4.6% raised the sensitivity of the %CDTTIA test to 0.76 with a specificity of 0.90. We conclude that this adaptation to the Array Protein System (Beckman-Coulter) is suitable for routine use and offers precise results. It, however, requires an adaptation of the cut-off value for patients and of the target value for kit controls.

Effects of oral ethanol on end-tidal CO₂tension in patients misusing alcohol

This study examines the effect of oral ethanol ingestion on P(et)CO₂ and other respiratory variables in alcohol-misusing subjects. Twelve patients were given a loading dose of alcohol (0.270 g/kg) followed by a second dose (0.135 g/kg) half an hour later, increasing blood alcohol to a mean of 82.0 +/- 10.3 (SEM) mg/100 ml at 1 hour. Five patients were classified as hazardous drinkers with evidence of mild alcohol dependence but no toxicity (Severity of Alcohol Dependency (SADQ) score < 15/60; serum carbohydrate-deficient transferrin < 6%). These patients showed a significant fall in mean end-tidal PCO² (P(et)CO₂) on alcohol (2.08 +/- 0.61 mm Hg; p = 0.027) with slightly increased ventilation (1.76 +/- 0.94 1 min(-1), p = 0.14); responses similar to those previously reported for normal subjects. Seven patients had evidence of moderate alcohol dependency and/or recent use (SADQ > 15/60; CDT > 6%). In these patients P et CO₂ did not fall after alcohol challenge (mean change + 0.61 mm Hg; p > 0.30). There were significant correlations between the changes in P et CO₂ and CDT (n = 12; r(s)= 0.66, p = 0.019) and SADQ (n = 11; r(s)= 0.688, p = 0.019). The results show that P(et)CO₂ control is abnormal in the alcohol dependency syndrome.

Alcohol intake, lipids and risks of myocardial infarction

The health effects of alcohol consumption remain complex for several reasons: the risks and benefits accrue over many years, assessment of drinking is generally based on self-report, drinking habits change over time and studies estimate average daily drinking disregarding how or when the beverage was consumed. In addition, alcohol consumption is associated with lifestyle factors which may confound relationship with disease. Despite these methodological difficulties, epidemiological studies are surprisingly consistent, showing that light to moderate intake is associated with a lower risk of total mortality compared with those who drink heavily or do not drink at all. Thus there is a J-shaped association of alcohol intake with risk of total mortality whose basis is likely to be the effect of summing the cause-specific effects at the various drinking levels. Studies using a diversity of methods and populations have consistently reported an inverse relationship between coronary heart disease and light to moderate drinking, with the depth and width of the J-shaped mortality curve depending on the underlying risk of coronary heart disease for that population. The higher risk of death at heavy drinking levels is due to increased risk of cancer, liver diseases, cardiomyopathy and stroke. The precise mechanisms behind these effects of alcohol are only now beginning to be understood. The most plausible mechanism by which alcohol reduces the risk of coronary heart disease is by its effects on blood lipids, particularly increases in high density lipoprotein (HDL) cholesterol: about 50% of the risk reduction attributable to alcohol is explained by changes in total HDL. Further support for the HDL hypothesis comes from the lack of a differential effect of alcohol by beverage type. While the association of alcohol and cardiovascular disease is likely to be causal, any public health recommendations must consider the complexity of alcohol's metabolic, physiological and psychological effects.