Diabetes is a disease caused by insufficient insulin. Although more prevalent in type 2 diabetics insulin resistance is fairly common in type 1 diabetics. Insulin resistance refers to a decrease in the sensitivity of cells to circulating levels of insulin. The liver is a primary target of the hormone insulin. Insulin resistance and persistent elevations in blood glucose contribute to the development of liver disorders in diabetics. Liver disease is common in both type 1 and type 2 diabetics and increases the risk for development of other diabetic complications, such as kidney, eye and cardiovascular disease.
Liver Enzymes
A measurement of liver enzymes in the blood is a commonly performed test to indicate changes in liver function and aid in the diagnosis of liver disorders. People with diabetes often have increased circulating levels of the liver enzymes, alanine aminotransferase and aspartate aminotransferase.
Glucose Production
The liver is the primary organ that synthesizes and exports glucose for use by other tissues. It also stores excess glucose as glycogen. Increased liver glucose production is partly causal of the elevated fasting glucose levels in type 2 diabetics. A study in the journal "Diabetes" reports that hepatic glucose production was increased up to 3-fold in type 2 diabetics. A review in "Clinical Diabetes" notes that approximately 80 percent of diabetics have elevated levels of glycogen in the liver. Although less common, increased liver glycogen content has also been reported in type 1 diabetics.
Liver Fat Content
Nonalcoholic fatty liver disease, or NAFLD, is characterized by excessive fat accumulation in the liver. A review published in the April 2009 issue of "Current Opinion in Endocrinology, Diabetes and Obesity" reports that approximately 70 percent of type 2 diabetics have NAFLD, and in these individuals, the course of the disease is more severe. A study in the October 2010 issue of the "Journal of Hepatology" reports that the prevalence of NAFLD in type 1 diabetics is 44 percent.
Nonalcoholic Steatohepatitis
Nonalcoholic steatohepatitis, or NASH, is a more progressive form of NAFLD and is characterized by both fatty liver and chronic liver inflammation. The chronic inflammation of the liver can eventually lead to substantial scarring of liver tissue and the development of cirrhosis. The review in "Clinical Diabetes" reports that nearly 30 percent of type 2 diabetics have liver fat accumulation with inflammation, and between 1 and 8 percent have cirrhosis. There are a few case reports of NASH also occurring in type 1 diabetics.
Hepatocellular Carcinoma
A review in the August 2010 issue of the "World Journal of Gastroenterology" reports that nearly 10 percent of people with NASH develop hepatocellular carcinoma and the incidence of hepatocellular carcinoma has increased more than two-fold between 1976 and 2002. This review also notes that more than 10 different studies found that type 2 diabetics have about a two-fold greater risk for developing hepatocellular carcinoma, and the risk is markedly higher in people that have type 2 diabetes and are obese. There are no studies that have evaluated the incidence of hepatocellular carcinoma in type 1 diabetics.
References
- "Clinical Diabetes"; Liver Disease and Diabetes Mellitus; Gavin N. Levinthal and Anthony S. Tavill; 1999
- "Diabetes"; Mechanism by which Metformin Reduces Glucose Production in Type 2 Diabetes; Ripudaman S. Hundal et al.; December 2000
- "Current Opinion in Endocrinology, Diabetes and Obesity"; Nonalcoholic Fatty Liver Disease in Type 2 Diabetes Mellitus; K. Cusi; April 2009
- "Journal of Hepatology"; Prevalence of Non-Alcoholic Fatty Liver Disease and its Association with Cardiovascular Disease in Patients with Type 1 Diabetes; G. Targher et al.; October 2010
- "World Journal of Gastroenterology"; Non-viral Causes of Hepatocellular Carcinoma; Wojciech Blonski; August 2010
