LONDON, Mar 21: Young men who were overweight or obese had a higher risk of developing severe liver disease or liver cancer later in life, a large Swedish population-based study found.
Compared with normal-weight men, those who were overweight at age 18 or 19 had a higher risk for severe liver disease over a follow-up period of nearly 3 decades (hazard ratio 1.49, 95% CI 1.35-1.64), reported Hannes Hagström, MD, PhD, of the Karolinska University Hospital in Stockholm, and colleagues.
For young men who were obese, the increased risk was even greater (HR 2.17; 95% CI 1.82-2.59), they wrote online in Gut.
Development of type 2 diabetes (T2DM) further increased the risk for severe liver disease across all weight categories, the authors noted. For example, men with obesity and type 2 diabetes had an even higher risk of severe liver disease (HR 3.28, 95% CI 2.27-4.74).
The risk of developing hepatocellular carcinoma (HCC) also increased for young men who were overweight (HR 1.57, 95% CI 1.01-2.45) and obese (HR 3.59, 95% CI 1.85-6.99).
Previous studies using self-reported BMIs have presented similar findings, the investigators noted. “The results from our population-based study with objectively measured BMIs however confirm these suggested findings even when adjusting for potential confounders, and add important information that this increased risk seems to be present from an early age,” they said.
“In this large population-based study of more than 1.2 million men, higher BMI in young adulthood was strongly associated with an increased risk of subsequent severe liver disease and HCC. This risk was most pronounced in men with concurrent T2DM. 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,” the authors stated.
The study included all males in Sweden who were conscripted into military service from 1969 to 1996. Conscription was mandatory at this time, so the study population included the vast majority (97%) of military-aged men. All men underwent extensive physical and cognitive testing at the time of conscription.
The investigators followed these men for a mean of 28.5 years. Follow-up started at 1 year after conscription and continued until Dec. 31, 2012. The investigators used national medical records databases to identify which men had been diagnosed with severe liver disease, liver cancer, and type 2 diabetes. They then used Cox proportional hazard models to estimate hazard ratios for the association between BMI (18.5–22.5 as reference) and these conditions, adjusting for potential confounders including age, education, cognitive ability, cardiovascular fitness, and blood pressure.
“The association between a high BMI and NAFLD [non-alcoholic fatty liver disease] is strong, and it is likely that part of the association between adolescent high BMI, T2DM, and future severe liver disease and HCC is attributable to development of NAFLD. In fact, around 70% of subjects with T2DM will have NAFLD,” the authors said.
Excluding cases with a diagnosis of viral, alcoholic, or autoimmune liver disease did not change the results significantly, “indicating that the main driver of severe liver disease in adolescent men is likely NAFLD,” they wrote.
Study limitations included the lack of data on women, the fact that it did not assess changes in BMI during follow-up, and that it did not include data on alcohol consumption or smoking.
“It is likely that the increased prevalence of overweight and obesity will lead to an increase in the total number of cases with severe liver disease in the future, including an increasing incidence of HCC,” the authors explained. “The risk of a high BMI for severe liver disease seems to be present from an early age, and is highly accentuated by development of T2DM.”
“This could have implications for public health decision making, strengthening the need of targeted intervention against overweight and obesity at an early age, and it specifically highlights the risk of T2DM as a risk factor for liver disease. Screening of men with T2DM for presence of manifest liver disease using noninvasive, inexpensive scoring systems could be a way forward,” they wrote.