Context and objectives:
Non-alcoholic fatty liver disease (NAFLD) and dementia share common risk factors, including metabolic disorders. However, it is unclear whether NAFLD is associated with dementia risk. We investigated the association between NAFLD and dementia risk, as well as the role of cardiovascular complications, including heart disease and stroke.
In this matched population-based cohort study, we identified all Swedish patients aged ≥65 years with NAFLD identified in the National Patient Registry (NPR) between 1987 and 2016. These were matched with up to to ten reference individuals from the population by age, sex and municipality in the year of diagnosis.
The diagnosis of incident dementia was derived from the NPR or cause of death register up to 2016. Adjusted hazard ratios (aHR) and 95% confidence intervals (CI) were calculated using models Cox regression.
A total of 2,898 NAFLD patients and 28,357 matched controls were identified (median age at admission, interquartile range [RIC]70 ; 55.1% women).
During a median follow-up of 5.5 years (IQR: 8.5 years), 145 (5.0%) NAFLD patients and 1291 (4.6%) control subjects were diagnosed with dementia. Compared to control individuals, NAFLD patients had higher rates of dementia (aHR 1.38, 95% CI 1.10-1.72) and vascular dementia (aHR 1.44, 95% CI 0.96 -2.23, p=0.07).
Comorbid NAFLD and heart disease (aHR 1.50 95% 1.08–2.05) or stroke (aHR 2.60 95% CI 1.95–3.47) confer an increased risk of dementia.
Non-alcoholic fatty liver disease (NAFLD) had a modest association with higher rates of dementia. It was strongest among NAFLD patients diagnosed with cardiovascular comorbidities.
Classification of evidence: This study provides class II evidence that non-alcoholic fatty liver disease is associated with the development of vascular and non-vascular dementia.