medwireNews: Individuals with hepatitis C virus (HCV) infection are at increased risk for developing Type 2 diabetes only if they have elevated alanine aminotransferase (ALT) levels, show study findings published in the American Journal of Gastroenterology.
The authors dismissed the results of previous studies showing a direct association between anti-HCV antibodies at baseline and higher incidence of Type 2 diabetes at follow-up.
In total, 2472 individuals from the electoral register of a town in Southern Italy were randomly selected and followed up over a 20-year period in 1985, 1992, and 2005. At each time point, individuals filled in a questionnaire and gave a blood sample to measure blood glucose and other serum variables including ALT. Anti-HCV antibodies were measured at the first and second timepoints.
Authors Giovanni Misciagna (IRCCS Savierio de Bellis, Bari, Italy) and colleagues found a higher prevalence of diabetes in patients with anti-HCV antibodies in 1985 and 1992. Furthermore, patients with anti-HCV antibodies had a higher incidence of Type 2 diabetes during 1985-1992 compared with 1992-2005.
Regression analysis controlling for gender, age, BMI, and ALT revealed no direct association between Type 2 diabetes and anti-HCV antibodies. However, Type 2 diabetes was associated with increased ALT at baseline. Indeed, HCV was shown to be associated with a 1.47-fold significantly increased risk for Type 2 diabetes only if ALT was elevated compared with negative HCV and ALT status.
The same direct association between anti-HCV antibodies and Type 2 diabetes in the presence of elevated ALT was also observed when the authors used changes in blood glucose levels instead of incident cases of Type 2 diabetes.
"Increased ALT values may be due to either HCV or conditions such as metabolic syndrome or steatohepatitis independently from HCV, conditions that could cause insulin resistance and then [Type 2 diabetes]," say the researchers.
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