Nonalcoholic fatty liver disease linked to increased risk for dementia

Patients with nonalcoholic fatty liver disease had an increased risk for dementia, with stronger risk existing for those with comorbid heart disease or stroke, according to a study published in Neurology.

“Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, affecting 25% of the global population,” Ying Shang, PhD, of the department of medicine at the Karolinska Institute, Sweden, and colleagues wrote. “While such metabolic disorders are not unique for NAFLD or dementia, it is unclear if NAFLD contributes to dementia independent of these factors.”

Shang and fellow researchers sought to explore associations between NAFLD and dementia risk, as well as the role of cardiovascular complications, including heart disease and stroke. They commenced a population-based matched cohort study that included 2,898 patients from Sweden aged at least 65 years with a diagnosis of NAFLD identified from the National Patient Register (NPR) between 1987 and 2016. These were paired with 28,357 controls from the general population based on age, sex and municipality at the year of diagnosis. Incident dementia diagnosis was derived from the NPR or the Cause of Death Register until 2016. Adjusted HRs and 95% CIs were estimated with Cox regression models.

Results showed that of all NAFLD patients, 105 (3.6%) had cirrhosis of the liver at baseline, and, in general, participants with NAFLD were more likely to have metabolic disorders, cardiovascular comorbidities and depression than matched counterparts.

Over a median follow-up of 5.5 years (interquartile range [IQR] = 8.5 years), 145 (5%) patients with NAFLD and 1,291 (4.6%) reference individuals were diagnosed with dementia. Compared with the control population, patients with NAFLD 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). Comorbid NAFLD and either heart disease (aHR = 1.5; 95% CI, 1.08-2.05) or stroke (aHR = 2.6; 95% CI, 1.95-3.47) additionally indicated a greater risk of dementia.

“These results highlight the possibility that targeted treatment of NAFLD, and cardiovascular comorbidities may reduce the risk of dementia,” Shang and colleagues wrote.