Self-reported dietary intake of potassium, calcium, and magnesium and risk of dementia in the Japanese: The hisayama study

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.