Background: Hepatitis C virus (HCV) affects glucose and lipid metabolism in vitro; however, it is unclear whether HCV infection is associated with insulin resistance and atherosclerosis at the population level. We aimed to investigate this association in a Japanese cohort of the Seven Countries Study, and our investigation was conducted in Tanushimaru, an HCV hyperendemic area.
Methods: A total of 1908 inhabitants of Tanushimaru were classified into 3 groups according to HCV infection status: those who were uninfected (n = 1780), those with transient infection (n = 88), and those with chronic infection (n = 40). Insulin resistance and atherosclerosis were evaluated by homeostasis model assessment for insulin resistance (HOMA-IR) and carotid intima-media thickness (IMT), respectively. Intergroup differences in variables were evaluated by age- and sex-matched multivariate regression analysis.
Results: Significant intergroup differences were seen in fasting glucose and insulin levels. The HOMA-IR value was significantly higher in the group with chronic infection than the values in the uninfected and transiently infected groups (3.0 ± 0.39 vs. 1.3 ± 0.03 vs. 1.5 ± 0.14; P < 0.001). In contrast, low-density lipoprotein (LDL)-cholesterol and triglyceride levels were significantly lower in the group with chronic infection than the levels in the other groups. IMT was reduced in the group with chronic infection, with a significant intergroup difference (0.67 ± 0.02 vs. 0.71 ± 0.003 vs. 0.72 ± 0.01 mm; P = 0.003).
Conclusions: This population-based study in an HCV hyperendemic area revealed that chronic HCV infection was associated with severe insulin resistance and with mild atherosclerosis, suggesting a unique characteristic of HCV-related metabolic abnormality.