Adolescent Nonalcoholic Fatty Liver Disease and Type 2 Diabetes in Young Adulthood

CONTEXT: The long-term risk of type 2 diabetes in adolescents with nonalcoholic fatty liver disease (NAFLD) is unclear. OBJECTIVE: To assess type 2 diabetes risk among adolescents with NAFLD. DESIGN AND SETTING: A nationwide, population-based study of Israeli adolescents who were examined before military service during 1997-2011 and were followed until December 31, 2016. PARTICIPANTS: A total of 1 025 796 normoglycemic adolescents were included. INTERVENTIONS: Biopsy or radiographic tests were prerequisite for NAFLD diagnosis. Data were linked to the Israeli National Diabetes Registry. MAIN OUTCOME MEASURES: Type 2 diabetes incidence. RESULTS: During a mean follow-up of 13.3 years, 12 of 633 adolescents with NAFLD (1.9%; all with high body mass index [BMI] at baseline) were diagnosed with type 2 diabetes compared with 2917 (0.3%) adolescents without NAFLD. The hazard ratio (HR) for type 2 diabetes was 2.59 (95% confidence interval [CI], 1.47-4.58) for the NAFLD vs. the non-NAFLD group after adjustment for BMI and sociodemographic confounders. The elevated risk persisted in several sensitivity analyses. These included an analysis of persons without other metabolic comorbidities (adjusted HR, 2.75 [95% CI, 1.48-5.14]) and of persons with high BMI; and an analysis whose outcome was type 2 diabetes by age 30 years (adjusted HR, 2.14 [95% CI, 1.02-4.52]). The results remained significant when a sex-, birth year-, and BMI-matched control group was the reference (adjusted HR, 2.98 [95% CI, 1.54-5.74]). CONCLUSIONS: Among normoglycemic adolescents, NAFLD was associated with an increased adjusted risk for type 2 diabetes, which may be apparent before age 30 years.