Influence of alcohol use, ethnicity, age, gender, BMI and smoking on the serum transferrin glycoform pattern: implications for use of carbohydrate-deficient transferrin (CDT) as alcohol biomarker

BACKGROUND: An alcohol-induced change in the serum transferrin glycoform pattern, carbohydrate-deficient transferrin (CDT), is used as a biomarker for detection and follow-up of heavy alcohol consumption. Besides studying the effects of drinking, this study evaluated any baseline differences in the transferrin pattern in relation to ethnicity, age, gender, body mass index (BMI) and smoking, as these could be confounders causing bias in CDT testing. METHODS: The transferrin glycoform pattern was determined in 1387 sera (68% men, 32% women) collected in Australia, Brazil, Canada, Finland and Japan from subjects classified as non-drinkers, light/moderate drinkers, or heavy drinkers by use of the WHO/ISBRA Interview Schedule. The iron-saturated glycoforms were separated by an HPLC candidate reference method, and the relative amounts of individual glycoforms to total transferrin were determined. RESULTS: In non-drinkers, the differences in the serum transferrin glycoform pattern in relation to ethnicity, age, gender and BMI were small and mostly not statistically significant. A higher disialotransferrin level in smokers compared with non-smokers could largely be explained by a higher alcohol intake in smokers. In the drinking subgroups, the main CDT glycoform disialotransferrin showed a positive correlation (r=0.80) with asialotransferrin, and disialo- and asialotransferrin a negative correlation with tetrasialotransferrin, that was dependent on the alcohol consumption level. CONCLUSIONS: With respect to CDT testing, the results indicated that adjustment of reference intervals for disialotransferrin and CDT in relation to ethnicity, age, gender, BMI and smoking is not required.