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Drinkers who are overweight are much more likely to develop deadly liver disease, according to scientists from the University of Glasgow.

In a study conducted by Dr Carole Hart of the Section of Public Health and Health Policy, scientists examined whether a raised Body Mass Index (BMI) and alcohol consumption acted together to increase the risk of liver disease.

The researchers looked at figures from two separate Midspan studies – large occupational and general population health surveys based in the West of Scotland which began in the 1960s and involved nearly 30,000 people.

On examining the results, published in the latest edition of the BMJ, the researchers found that the combination of drinking and being overweight or obese led to a much greater risk of liver disease than either alcohol consumption or overweight/obesity alone.

Dr Hart said: “There was already considerable evidence that on their own, both alcohol consumption and raised BMI were risk factors for developing liver disease.

“What our study has shown is that when both these factors are combined there is a supra-additive effect, meaning the risk of developing liver disease is even higher than the sum of their separate effects.

The rate of chronic liver disease in Scotland has trebled in the last 15 years – it was responsible for 9,072 hospital admissions and 1,059 deaths in 2008.

The figures used by the researchers came from the first Midspan study, known as the Main study, originally gathered between 1965 and 1968 from male participants aged 18-92, and from the Collaborative Midspan study, gathered between 1970 and 1973 from men aged 21-75.

Participants were asked to complete a questionnaire about their usual weekly consumption of alcohol, smoking habits and general health. They were then medically examined with blood pressure, lung capacity and electrocardiogram, as well as weight and height, measurements taken.

Subjects were then tracked through the NHS Central Register and the study was notified of dates of death and causes.

Just under half of the 9,559 men included in this study were overweight or obese, while 80 (0.8%) died with liver disease as the main cause of death, and 146 (1.5%) died with liver disease mentioned in any of the causes of death.

Overweight (BMI of 25 to <30) men had higher death rates than normal weight men while obese men (BMI of 30 or more) had a five-fold increase in the risk of dying of liver disease.

Drinkers of 15 or more units a week of alcohol in any BMI category, and obese drinkers had higher risks of liver disease mortality than normal weight non-drinkers. Risks increased as BMI and alcohol levels increased. Obese men drinking 15 or more units a week had almost 19 times higher risk of dying of liver disease.

Dr Hart added: “There are limitations to this study, such as the fact that liver function was not measured at the time of the original health screening and that BMI and alcohol consumption might have changed over time, but nevertheless, these results still have important clinical and public health implications.

“We may need to consider recommending lower ‘safe’ limits of alcohol consumption for people who are overweight.”

The £22,326 research project was funded by the Chief Scientist’s Office of the Scottish Government.

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For more information contact Stuart Forsyth in the University of Glasgow Media Relations Office on 0141 330 4831 or email s.forsyth@admin.gla.ac.uk

First published: 12 March 2010