Milk and dairy consumption and risk of dementia in an elderly Japanese population: the Hisayama Study

Abstract

Objectives: To determine the effect of milk and dairy intake on the development of all-cause dementia and its subtypes in an elderly Japanese population.

Design: Prospective cohort study.

Setting: The Hisayama Study, Japan.

Participants: Individuals aged 60 and older without dementia (N = 1,081).

Measurements: Milk and dairy intake was estimated using a 70-item semiquantitative food frequency questionnaire grouped into quartiles. The risk estimates of milk and dairy intake on the development of all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD) were computed using a Cox proportional hazards model.

Results: Over 17 years of follow-up, 303 subjects developed all-cause dementia; 166 had AD, and 98 had VaD. The age- and sex-adjusted incidence of all-cause dementia, AD, and VaD significantly decreased as milk and dairy intake level increased (P for trend = .03 for all-cause dementia, .04 for AD, .01 for VaD). After adjusting for potential confounders, the linear relationship between milk and dairy intake and development of AD remained significant (P for trend = .03), whereas the relationships with all-cause dementia and VaD were not significant. The risk of AD was significantly lower in the second, third, and fourth quartiles of milk and dairy intake than in the first quartile.

Conclusion: Greater milk and dairy intake reduced the risk of dementia, especially AD, in the general Japanese population.

Keywords: Alzheimer's disease; dementia; milk and dairy; vascular dementia.