The relationship between obesity and liver disease is investigated in a recent large-scale study.
Already, in some American states, more than 35 percent of the population are obese.
Over recent years, links between obesity in youth and liver disease later in life have also become clear. These liver diseases include chronic viral hepatitis B and C, as well as non-alcoholic liver disease.
Links between liver disease and BMI
Earlier studies have demonstrated that a high BMI in adolescent men is associated with an increased risk of death from, or hospitalization for, end-stage liver disease later in life. Even when variables such as alcohol consumption, smoking, and the use of narcotics were taken into account, the relationship was still significant. However, to date, this link between BMI and liver disease has not been examined in sufficient depth.
A group of Swedish researchers set out to plug this gap. Led by Dr. Hannes Hagström, of the Centre for Digestive Diseases at the Karolinska University Hospital in Sweden, they delved into data from 1.2 million Swedish men who were conscripted into the army from 1969 to 1996.
They also used information from population-based registers charting liver cancer, severe liver disease, and type 2 diabetes. The participants were followed from 1 year after conscription, up until the end of 2012. Their findings are published this week in the journal Gut.
In all, the researchers collated and analyzed an impressive 34 million person-years. Across these huge swathes of data, there were 5,281 cases of severe liver disease, which included 251 cases of liver cancer.
50 percent increase in risk of liver disease
The investigators accounted for factors such as smoking and alcohol intake, but men who received a diagnosis of alcoholic liver disease during follow-up were removed from the data. Once these controls were in place, the findings were still significant.
The analysis showed that overweight men were almost 50 percent more likely to develop liver disease in later life than men of a normal weight. Similarly, obese men were more than twice as likely to develop liver disease further down the line.
This effect was even more pronounced for men who also developed type 2 diabetes. Participants with both obesity and type 2 diabetes were more than three times more likely to develop liver problems as they aged, compared with normal-weight men without type 2 diabetes.
The authors say of the results:
"This could have implications for public health decision-making, strengthening the need of targeted intervention against overweight and obesity at an early age and specifically highlights the risk of type 2 diabetes mellitus as a risk factor for liver disease."
Because this study was observational, conclusions regarding cause and effect can not be drawn. However, because the study was conducted on such a large scale, the findings should be taken very seriously. The authors conclude with a call to improve earlier interventions in people most at risk of liver conditions:
"Screening of men with type 2 diabetes mellitus for presence of manifest liver disease using noninvasive, inexpensive scoring systems could be a way forward."
Similarly, they call for weight issues to be tackled from an early age to prevent these types of problems from arising. They write: "Interventions to reduce the increasing prevalence of overweight and obesity should be implemented from an early age to reduce the future burden of severe liver disease on individuals and society."