Fatty Liver among Persons in a Community in Northern Italy

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The summary below is from the full report titled "Prevalence of and Risk Factors for Hepatic Steatosis in Northern Italy." It is in the 18 January 1999 issue of Annals of Internal Medicine (volume 131, pages 112-117). The authors are S. Bellentani, G. Saccoccio, F. Masutti, L.S. Crocè, G. Brandi, F. Sasso, G. Cristanini, and C. Tiribelli.

What is the problem and what is known about it so far?

Positive blood tests for liver abnormalities occur fairly often and can be caused by many different liver diseases. Steatosis (fatty deposits in the liver) is often the only condition found in people with abnormal liver tests. Fatty liver is usually a benign condition that does not progress to liver damage, although it can lead to worry and unnecessary medical testing. Little is known, however, about just how common fatty liver really is; we also have little information on the risk factors, such as alcohol use and obesity, that might be associated with it.

Why did the researchers do this particular study?

The researchers wanted to determine how common fatty liver actually is in a general population. They also wanted to see whether persons with fatty liver are more likely to drink alcohol and be overweight than persons without this condition.

Who was studied?

As part of a larger study of liver disease in two Northern Italian communities, the researchers studied four groups of people: 1) 2,753 normal-weight persons who drank little or no alcohol, 2) 283 obese persons who drank little or no alcohol, 3) 168 normal-weight persons who were heavy alcohol drinkers, and 4) 95 persons who were both obese and heavy alcohol drinkers.

How was the study done?

The researchers did physical examinations and performed blood tests for liver abnormalities and ultrasound tests of the liver on all study participants. The ultrasound was the test that showed whether there was fat in the liver. The ultrasound in combination with the other tests let the researchers rule out other types of liver disease.

What did the researchers find?

Fatty liver was present in 16% of normal weight non-drinkers, 46% of heavy drinkers, 76% of obese non-drinkers, and 95% of obese heavy drinkers.

What were the limitations of the study?

This study included only people living in two communities in a single country. It is unclear whether the same results would occur in different geographic regions. Although the researchers made every effort to accurately measure how much alcohol study participants drank, they used the participants' own estimates, and participants may not have accurately estimated how much alcohol they consume.

What are the implications of the study?

Both being overweight and drinking alcohol are associated with fatty liver, but being overweight appears to be associated with a greater accumulation of fat in the liver than does drinking alcohol.