SEARCH

SEARCH BY CITATION

Keywords:

  • vitamin D;
  • calcium;
  • dementia;
  • cognition;
  • mild cognitive impairment

Objectives

To examine the effects of vitamin D and calcium on cognitive outcomes in elderly women.

Design

Post hoc analysis of a randomized double-blind placebo-controlled trial.

Setting

Forty Women's Health Initiative (WHI) clinical centers across the United States.

Participants

Four thousand one hundred forty-three women aged 65 and older without probable dementia at baseline who participated in the WHI Calcium and Vitamin D Trial and the WHI Memory Study.

Intervention

Two thousand thirty-four women were randomized to receive 1,000 mg of calcium carbonate combined with 400 IU of vitamin D3 (treatment) and 2,109 to placebo.

Measurements

Primary: classifications of probable dementia or mild cognitive impairment (MCI) based on a four-phase protocol that included central adjudication. Secondary: global cognitive function and individual cognitive subtests.

Results

Mean age of participants was 71. During a mean follow-up of 7.8 years, 39 participants in the treatment group and 37 in the placebo group developed incident dementia (hazard ratio (HR) = 1.11, 95% confidence interval (CI) = 0.71–1.74, P = .64). Likewise, 98 treatment participants and 108 placebo participants developed incident MCI (HR = 0.95, 95% CI = 0.72–1.25, P = .72). There were no significant differences in incident dementia or MCI or in global or domain-specific cognitive function between groups.

Conclusion

There was no association between treatment assignment and incident cognitive impairment. Further studies are needed to investigate the effects of vitamin D and calcium separately, on men, in other age and ethnic groups, and with other doses.