Self-reported dietary intake of potassium, calcium, and magnesium and risk of dementia in the Japanese: the Hisayama Study

Abstract

Objectives: To investigate whether higher intake of potassium, calcium, and magnesium reduces the risk of incident dementia.

Design: Prospective cohort study.

Setting: The Hisayama Study, in Japan.

Participants: One thousand eighty-one community-dwelling Japanese individuals without dementia aged 60 and older.

Measurements: A 70-item semiquantitative food frequency questionnaire was used to assess potassium, calcium, and magnesium intakes. Hazard ratios (HRs) for the development of all-cause dementia and its subtypes were estimated using Cox proportional hazards model.

Results: During a 17-year follow-up, 303 participants experienced all-cause dementia; of these, 98 had vascular dementia (VaD), and 166 had Alzheimer's disease (AD). The multivariable-adjusted HRs for the development of all-cause dementia were 0.52 (95% confidence interval [CI] = 0.30-0.91), 0.64 (95% CI = 0.41-1.00), and 0.63 (95% CI = 0.40-1.01) for the highest quartiles of potassium, calcium, and magnesium intake, respectively, compared with the corresponding lowest quartiles. Similarly, the HRs for the development of VaD were 0.20 (95% CI = 0.07-0.56), 0.24 (95% CI = 0.11-0.53), and 0.26 (95% CI = 0.11-0.61) for the highest quartiles of potassium, calcium, and magnesium intake, respectively. There was no evidence of a linear association between these mineral intakes and the risk of AD.

Conclusion: Higher self-reported dietary intakes of potassium, calcium, and magnesium reduce the risk of all-cause dementia, especially VaD, in the general Japanese population.