5 July 2012

Research shows genetic factors ‘modestly’ affect alcoholic liver disease risk

Research has suggested that environmental factors have a greater impact on the risk of alcoholic liver disease (ALD) than genetic predisposition.

A team of researchers at the University of Sheffield and Sheffield Teaching Hospitals NHS Foundation Trust has published results this month in the European Journal of Gastroenterology and Hepatology showing that patients with ALD are no more likely to have relatives with ALD than are heavy drinkers without evidence of liver disease.

The results are based on a study comparing 291 heavy drinkers with liver disease with 208 participants with similar levels of alcohol consumption, but no evidence of liver disease (called the ‘control’ group).

Led by Dr Dermot Gleeson, Consultant Hepatologist, the team collected data on both groups of drinkers, through a questionnaire and a follow-up phone call, on drinking behaviour and the presence of liver disease in parents and siblings. Men who consume more than 60 units per week and women who consume more than 40 units per week were included.

Participants were asked questions about their drinking behaviours at different stages across their lives, and were asked to grade his or her relatives’ drinking behaviours as abstinent, light/social, moderate or heavy.

The results showed that the relatives of both groups had similar drinking habits, with similar proportions of each recorded as being abstinent (15.8 per cent for patients vs 16.1 per cent for controls), light/social (35.4 per cent vs 37.4per cent ), moderate (30.4 per cent vs 27.4per cent), and heavy (18.3 per cent vs 19.7 per cent) drinkers.

The frequency of any liver disease in the relatives of patients and controls was also similar, at 3.3 per cent vs 3.1 per cent. Furthermore, only a slightly higher percentage (12 per cent) of relatives of patients were reported to have ALD (defined as liver disease in a heavy drinker), compared to 9.7 per cent of the relatives of the control group.

ALD – liver damage caused by alcohol excess – is an important cause of mortality and ill-health in the developed world. Death rates linked to ALD have risen by more than two-thirds in the last 30 years in England, making alcohol one of the most common causes of death. However, only about 10 per cent of heavy drinkers develop severe liver disease, and the basis for this variable susceptibility remains unclear. Whilst it is widely recognised that a tendency to drink heavily does have a genetic component, it remains unclear to what extent genetic factors influence the risk of a heavy drinker developing ALD.

Dr Dermot Gleeson said: “ALD can have a severe impact on a person’s health and quality of life and can cause death. However, we still do not know exactly what impacts on a person’s risk of developing ALD.

“Our results point towards environmental factors as being more significant than genetic predisposition in determining the risk of a heavy drinker developing ALD. Although genetic predisposition may have an impact, we believe that this is likely to be modest. Environmental factors, for example diet, other medications, and infections may well have greater influence on a person’s risk.