Vitamin D + Calcium = Placebo for Cognitive Decline
Am Fam Physician. 2013 Jun 1;87(11):799.
Does calcium plus vitamin D prevent cognitive decline in older women?
Calcium plus vitamin D is no better than placebo in preventing cognitive decline in women older than 65 years. (Level of Evidence = 1b)
These authors used data from the Women's Health Initiative to compare cognitive outcomes in 2,034 women older than 65 years who received calcium (1,000 mg daily) plus vitamin D (400 IU daily) vs. 2,109 women who received placebo. The women were primarily non-Hispanic whites. The researchers assessed each woman's cognition at baseline and then annually for an average of eight years. The researchers used many cognitive assessment measures, including Consortium to Establish a Registry for Alzheimer's Disease (CERAD) tests, the Modified Mini-Mental State Examination, the Digit Span Forward and Backward test, the Primary Mental Abilities Vocabulary test, the Card Rotation test, the California Verbal Learning test, the Benton Visual Retention test, and the Finger Tapping test. CERAD test results were used to classify the primary outcome: probable dementia, mild cognitive impairment, or cognitively normal. The secondary outcome, the patient's global function, was assessed using the other tools. At the end of the study interval, using intention-to-treat analysis, the percentage of women who developed dementia or mild cognitive impairment was similar in each group (4.8% vs. 5.1% in the intervention and control groups, respectively). If one excludes nonadherent women from the analysis, the rates remain comparable (3.1% vs. 2.9% in the intervention and control groups, respectively). Because this latter approach tends to bias data in favor of interventions, it strengthens the conclusion that calcium plus vitamin D is no better than placebo in preventing cognitive decline.
Rossom RC, Espeland MA, Manson JE, et al. Calcium and vitamin D supplementation and cognitive impairment in the Women's Health Initiative. J Am Geriatr Soc. 2012;60(12):2197–2205
Funding source: Government
Study design: Randomized controlled trial (double-blinded)
POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, please see http://www.essentialevidenceplus.com.
For definitions of levels of evidence used in POEMs, see http://www.essentialevidenceplus.com/product/ebm_loe.cfm?show=oxford.
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