Association of non-alcoholic fatty liver disease with incident dementia later in life among elder adults

BACKGROUND/AIMS: Accumulating evidence suggests a link between non-alcoholic fatty liver disease (NAFLD) and brain health. However, population-based evidence on the association between NAFLD and dementia remains unclear. This study was conducted to determine the association between NAFLD and incident dementia. METHODS: The study population included 608,994 adults aged ≥60 years who underwent health examinations between 2009 and 2010. Data were collected from the Korean National Health Insurance Service database. NAFLD was assessed using the fatty liver index (FLI). A Cox proportional hazards regression model was used to determine the association between NAFLD and dementia. RESULTS: During the 6,495,352 person-years of follow-up, 48,538 participants (8.0%) developed incident dementia. The participants were classified into low (FLI <30), intermediate (FLI ≥30 and <60), and high (FLI ≥60) groups. In the overall study population, the FLI groups were associated with a risk of dementia (P for trend <0.001). After propensity score matching, a low FLI was associated with a reduced risk of dementia (adjusted hazard ration [aHR], 0.96; 95% confidence interval [CI], 0.93–0.98; P=0.002), whereas a high FLI (NAFLD) was associated with an increased risk of dementia (aHR, 1.05; 95% CI, 1.02–1.08; P=0.001). A higher risk of dementia in the high FLI group than in the intermediate FLI group was attributed to Alzheimer’s disease (aHR, 1.04; 95% CI, 1.01–1.07; P=0.004) rather than vascular dementia (aHR, 0.94; 95% CI, 0.75–1.18; P=0.602). CONCLUSIONS: NAFLD was associated with an increased risk of dementia, which was attributed to an increased risk of Alzheimer’s disease.