The Dietary Fiber Intake and the Risk of Disabling Dementia: The JPHC Disabling Dementia Study

We evaluated the association between the dietary fiber intake and the risk of dementia.

We performed a prospective study within the Japan Public Health Center-based Prospective Study involving 41,467 Japanese individuals aged 45-74 years between 1995-1998. Information regarding food intake was collected using a food frequency questionnaire. Disabling dementia was detected using the National Long-term Insurance System between 2006 and 2016. We calculated the hazard ratios and 95% confidence intervals for disabling dementia according to quartiles of soluble, insoluble, and total fiber intake and dietary fiber intake from food groups (cereals, potatoes and starches, soybeans, vegetables, and fruits) intake by sex.

During an average follow-up period of 9.4, 4910 cases of disabling dementia were documented. The total fiber intake was inversely associated with the risk of disabling dementia in both men and women. The multivariable hazard ratios (95% confidence intervals: CIs) of disabling dementia for the highest versus lowest quartiles of total fiber intake were 0.82 (0.73-0.91) in women (p for trend ＜0.001) and 0.86 (0.74-1.00) in men (p for trend = 0.03). Similar inverse associations between soluble and insoluble fiber intake and the risk of disabling dementia were observed. The dietary fiber intake from cereals, potatoes, starches, vegetables, and fruits, but not soybeans, was inversely associated with the risk of disabling dementia, with some variation by sex.

The dietary intake of total, soluble, and insoluble fiber was associated with a lower risk of disabling dementia. The associations did not vary materially according to the food source of the fiber.