TORONTO—Nonalcoholic fatty liver disease seems to accelerate physical brain aging by as much as seven years, according to a new subanalysis of the ongoing Framingham Heart Study. However, while the finding suggests that the liver disorder directly endangers brains, the study also offers hope, said Galit Weinstein, MSc, PhD, at the 2016 Alzheimer’s Association International Conference. “If indeed nonalcoholic fatty liver disease is a risk factor for brain aging and subsequent dementia, then it is a modifiable one,” said Dr. Weinstein, an Adjunct Assistant Professor of Neurology at Boston University. “We have reason to hope that nonalcoholic fatty liver disease remission could possibly improve cognitive outcomes.”
She and her colleagues examined the relationship of nonalcoholic fatty liver disease and total brain volume in 906 subjects enrolled in the Framingham Offspring Cohort. This substudy was initiated in 1971 and includes 5,124 children of the original Framingham cohort.
For their study, the researchers assessed the presence of nonalcoholic fatty liver disease by abdominal CT scans and white-matter hyperintensities and brain volume (total, frontal, and hippocampal) by MRI. The resulting associations were then adjusted for age, sex, alcohol consumption, visceral adipose tissue, BMI, menopausal status, systolic blood pressure, current smoking, diabetes, history of cardiovascular disease, physical activity, insulin resistance, and C-reactive protein.
There were no significant associations with white-matter hyperintensities or with hippocampal volume, but the researches did find a significant association with total brain volume. Even after adjustment for all of the covariates, patients with nonalcoholic fatty liver disease had smaller-than-normal brains for their age. This result can be seen as a pathologic acceleration of the brain aging process, Dr. Weinstein said.
The finding was most striking among the youngest subjects, she said, accounting for about a seven-year advance in brain aging for those younger than 60. Older patients with nonalcoholic fatty liver disease showed about a two-year advance in brain aging.
The effect is probably mediated by the liver’s complex interplay in metabolism and vascular functions, Dr. Weinstein said.
—Michele G. Sullivan
