Despite widespread use of multivitamin supplements, their effect on cognitive health – a critical issue with aging – remains inconclusive. To date, there have been no long-term clinical trials to study multivitamin use and cognitive decline in older persons.
To evaluate whether long-term multivitamin supplementation affects cognitive health in later-life.
Randomized, double-blind, placebo-controlled trial of a multivitamin from 1997 to June 1, 2011. The cognitive function sub-study began in 1998; we completed up to four repeated cognitive assessments by telephone interview over 12 years.
The Physicians’ Health Study II.
5,947 male physicians aged ≥ 65 years.
Daily multivitamin, or placebo.
A global composite score averaging 5 tests of global cognition, verbal memory, and category fluency. The secondary endpoint was a verbal memory score combining 4 tests of verbal memory, a strong predictor of Alzheimer disease.
There was no difference in the mean cognitive change over time between the multivitamin and placebo groups, or in the mean level of cognition at any of the four assessments. Specifically, for the global composite score, the mean difference in cognitive change over follow-up was −0.01 (95% confidence interval [CI] −0.04, 0.02) standard units, comparing treatment versus placebo. Similarly, there was no difference in cognitive performance between the treated and placebo groups on the secondary outcome, verbal memory (e.g., mean difference in cognitive change over follow-up=−0.005, 95% CI −0.04, 0.03).
Doses of vitamins may be too low, or population may be too well-nourished to benefit from multivitamin.
In male physicians aged ≥ 65 years, long-term use of a daily multivitamin did not provide cognitive benefits.
http://www.clinicaltrials.gov identifier: NCT00270647