Obesity, Alcohol and Liver Disease

Chronic liver disease, including cirrhosis, is the 12th most common cause of death in the United States, alone, and causes nearly 30,000 deaths per year in America. Increased alcohol intake and obesity are both known risk factors for chronic liver disease.  Moreover, recent research has suggested that the combination of alcohol intake and obesity may synergistically increase the risk of chronic liver disease above and beyond the sum of these two risk factors.  

Two newly published prospective, randomized clinical research studies from the United Kingdom further suggest that increased alcohol intake in the presence of obesity significantly increases the risk of chronic liver disease, and premature death related to chronic liver disease.  Both of these studies appear in the current issue of the British Medical Journal.

In the first study, more than 1.2 million women (average age was 56 years) were recruited between 1996 and 2001.  In this Million Woman Study, after an average duration of follow-up of 6.2 years, 1,811 women were either admitted to a hospital with a new diagnosis of cirrhosis, or died of cirrhosis.  

Based upon the extensive health data collected from all of the participants in this enormous public health study, both obesity and alcohol intake were proportionally linked to an increased risk of cirrhosis, as well as death due to cirrhosis.  (Note: a standard glass of wine, mixed drink, or beer contains about 0.6 ounces, or 14 grams, of alcohol.)

For every 5 units of BMI above 22.5, the relative risk of cirrhosis increased by 28 percent (BMI is a standard measure of body fat content that is adjusted for height and weight).  Among women who reported the consumption of less than 70 grams of alcohol per week (equivalent to 5 alcoholic drinks per week), the absolute risk of developing cirrhosis, over a period of 5 years, was 20 percent higher in women with a BMI of 30 or more, when compared to non-obese women with normal BMIs (“obesity” is defined as a BMI of 30, or greater; while being “overweight is defined as having a BMI of 25 or greater, but less than 30).  

Among the women who reported consuming 150 grams or more of alcohol per week (which is equivalent to 11 or more alcoholic drinks per week), a normal BMI was associated with a 170 percent increase in the absolute risk of developing cirrhosis, while obese women (with a BMI of 30 or greater) who consumed 150 grams or more of alcohol per week experienced a whopping 400 percent increase in the risk of developing cirrhosis!  

When this data was extrapolated to the population of the United Kingdom, as a whole, it was determined that alcohol consumption, particularly at higher levels, accounted for 42 percent of all cases of non-fatal and fatal cirrhosis in middle-aged women, while obesity caused an additional 17 percent of all non-fatal and fatal cases of cirrhosis of the liver.

In the second published study in the British Medical Journal, data from two prospective clinical studies was analyzed.  A total of 9,559 men participated in these prospective public health studies, with a highly impressive median follow-up of 29 years.  These nearly 10,000 male study participants were divided into separate study groups based upon their measured BMI and their self-reported alcohol intake.

During nearly 3 decades of observation, 80 (0.8 percent) of these male research volunteers died directly due to chronic liver disease, while another 146 (1.5 percent) died of multiple causes, but with liver disease as a contributing cause of death.

As with the previous study, there were significant interactions between alcohol intake, BMI, and chronic liver disease (after adjusting for other known risk factors for chronic liver disease).  In this study, the consumption of 15 or more alcoholic drinks per week in volunteers with a normal BMI more than doubled the relative risk of dying of chronic liver disease when compared to other non-obese men who consumed less than 15 drinks per week.  

Among the overweight (but not obese) men who consumed 15 or more alcoholic drinks per week, the relative risk of death due to chronic liver disease was more than 7 times higher than was observed in overweight men who consumed significantly less than 15 drinks per week.  Finally, and most disconcertingly, obese men who consumed 15 or more alcoholic drinks per week experienced nearly 18 times the relative risk of dying from chronic liver disease as compared to their obese counterparts who drank significantly less alcohol.

(Even among obese men who consumed 14 or fewer alcoholic drinks per week, the relative risk of death due to chronic liver disease was still more than 4 times higher than what was observed in obese men who did not drink alcoholic drinks at all.)

Based upon this data, the researchers conducting this study were able to determine that there was a synergistic, enhanced risk of dying from liver disease when alcohol intake was present in addition to being overweight or obese.  This “relative excess risk” due to an interaction between alcohol intake and increasing BMI amounted to 4 times the relative risk of simply adding the individual liver disease risks of increased BMI and alcohol intake.

Taken together, these two large prospective public health studies confirm previous observations that both rising levels of excess weight and increasing levels of regular alcohol intake are associated, both separately and together, with an increased risk of chronic liver disease, and death due to chronic liver disease. 

Moreover, the combination of obesity and increased alcohol intake appears to be a particularly severe risk factor for the development of chronic liver disease, and for death due to liver disease.  

Therefore, in addition to the multiple other health risks associated with obesity and excessive alcohol intake, the results of these two studies should cause all of us to reexamine our lifestyle and dietary habits in our pursuit of better health and greater longevity.