Biomarkers of alcohol use and related health risks

Onni Niemelä1,*

1Laboratory Medicine, Seinäjoki Central Hospital and University of Tampere, Tampere, Finland

Excessive use of alcohol consumption causes enormous morbidity and mortality worldwide. Liver is the main target of ethanol toxicity due to its primary role in ethanol metabolism. Measurements of liver enzyme activities (GGT, ALT, AST) are important screening tools for detecting abnormal liver function. However, due to lack of ethanol-specificity and inconsistencies regarding the definitions of significant alcohol consumption, several other blood tests are usually needed to exclude competing and co-existing causes of tissue toxicity. Information on the specific role of ethanol consumption behind health disorders may be obtained through measurements of blood ethanol and its specific metabolites (ethyl glucuronide, phosphatidylethanol, protein-acetaldehyde condensates and associated autoimmune responses). Recent evidence has also indicated that being overweight is another highly common cause of abnormal liver enzyme levels. The presence or absence of adiposity may also modulate the risk of ethanol consumption in creating the detrimental health effects. Interestingly, increased liver enzyme activities in circulation may reflect not only hepatic function but can also serve as indicators of general health and the status of oxidative stress in vivo. ALT and GGT activities have been shown to be closely associated with insulin resistance, metabolic syndrome, mortality from coronary heart diseases and even mortality from all causes. Recent clinical evidence also supports a close link between fatty liver, GGT levels and the development of cardiovascular disease. If the upper normal limits for liver enzyme activities were defined based on the data obtained from normal weight abstainers, the clinical value of liver enzyme measurements as screening tools and in patient follow-up could be significantly improved.

Keywords: Biomarker, Liver