Combined Effect of Nonalcoholic Fatty Liver Disease and Impaired Fasting Glucose on the Development of Type 2 Diabetes: A 4-year retrospective longitudinal study

OBJECTIVE: To evaluate whether there is a difference in the association between nonalcoholic fatty liver disease (NAFLD) and incident diabetes based on the presence of impaired fasting glucose. RESEARCH DESIGN AND METHODS: A total of 7,849 individuals (5,409 men and 2,440 women) without diabetes, who underwent comprehensive health check-ups annually for 5 years, were categorized into four groups by the presence of impaired fasting glucose and NAFLD at baseline. The association between NAFLD and incident diabetes was evaluated separately in groups with normal and impaired fasting glucose. RESULTS: For 4 years, the incidence of diabetes in the NAFLD group was 9.9% compared with 3.7% in the non-NAFLD group, with multivariable-adjusted hazard ratio of 1.33 (95% CI 1.07–1.66). However, this higher risk for diabetes only existed in the impaired fasting glucose group. CONCLUSIONS: Our study suggests that NAFLD has an independent and additive effect on the development of diabetes under conditions of impaired insulin secretion.