Nonalcoholic Fatty Liver Disease Incidence and Impact on Metabolic Burden and Death: a 20 Year-Community Study

ABSTRACT

Recent population-based data on nonalcoholic fatty liver disease (NAFLD) epidemiology in general and incidence in particular, are lacking. We examined trends in NAFLD incidence in a US community, and the impact of NAFLD on incident metabolic comorbidities (MC), cardiovascular (CV) events and mortality. A community cohort of all adults diagnosed with NAFLD in Olmsted County, MN between 1997-2014 was constructed using the Rochester Epidemiology Project database. The yearly incidence rate was calculated. The impact of NAFLD on incident MC, CV events and mortality was studied using a multi-state model, with a 4:1 age and sex-matched general population as reference. We identified 3,869 NAFLD subjects (median age 53, 52% women) and 15,209 controls; median follow-up was 7 (1 to 20) years. NAFLD incidence increased 5-fold, from 62 to 329/100,000 person-years. The increase was highest (7-fold) in young adults, age 18-39 years. The 10-year mortality was higher in NAFLD subjects (10.2%) than controls (7.6%) (p<0.0001). NAFLD was an independent risk factor for incident MC and death. Mortality risk decreased as the number of incident MC increased: RR= 2.16 (95% CI 1.41-3.31), 1.99 (95% CI 1.48-2.66), 1.75 (95% CI 1.42-2.14) and 1.08 (95% CI 0.89-1.30) when 0, 1, 2, or 3 MC were present, respectively. The NAFLD impact on CV events was significant only in subjects without MC (RR=1.96, 95% CI=1.35-2.86). NAFLD reduced life expectancy by 4 years, with more time spent in high metabolic burden. Conclusion: The incidence of NAFLD diagnosis in the community has increased 5-fold, particularly in young adults. NAFLD is a consequence but also a precursor of MC. Incident MC attenuates the impact of NAFLD on death and annuls its impact on CV disease. This article is protected by copyright. All rights reserved.

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