Daily multivitamins didn’t slow age-related cognitive decline, according to a multiyear, placebo-controlled study of almost 6,000 elderly male physicians.
"We saw no benefit of a daily multivitamin in slowing cognitive decline after more than a decade of treatment and follow-up. Long-term use of a daily multivitamin did not provide cognitive benefits," concluded investigators led by Francine Grodstein, Sc.D., and Jacqueline O’Brien, Sc.D., both of Brigham and Women’s Hospital, Boston, in an article published Dec. 16 in Annals of Internal Medicine.
As part of the Physicians’ Health Study II, 2,980 male physicians at least 65 years old were randomized to daily Centrum Silver (Pfizer) and 2,967 others to placebo. The groups had no significant differences in alcohol use, smoking, cardiovascular disease, diabetes, hypertension, hypercholesterolemia, exercise, or depression. The mean age at enrollment in both groups was about 72 years.
The men then took the East Boston Memory Test, the Telephone Interview for Cognitive Status (TICS), and other validated tests from which global composite and verbal memory scores were calculated. Testing was repeated three more times over an average duration of 8.5 years.
The researchers found no significant differences between the two groups over time in cognitive function change. During the follow-up period, the average difference in change between the multivitamin and placebo groups was –0.01 standard unit (confidence interval, –0.04 to 0.02) for the global composite score and –0.005 SU (CI, –0.04 to 0.03) for the verbal memory score. "At each follow-up assessment, there were no differences between the mean global composite" and verbal memory scores, the investigators said.
Likewise, multivitamins had no protective effect in subanalyses based on smoking, alcohol intake, body mass index, diabetes, hypertension, hypercholesterolemia, diet, depression, or folate use.
About 84% of patients in both groups reported taking at least two-thirds of their study pills. Overall, there was a mean yearly drop of 0.16 points on the 50-point TICS scale.
"A limitation of this study is that our population of male physician participants may have been too well nourished to observe benefits of supplementation," the investigators said. "This population is also unique in that the participants are all highly educated men, so it is possible that effects of multivitamins could have been different in a study population with varying levels of educational attainment."
Previous randomized, controlled studies of multivitamins and cognition have not shown benefits in patients who are well nourished, the researchers noted. "Trials testing high doses of individual vitamin supplements have generally had null results for cognition as well, including large-scale trials of antioxidant supplements and B vitamins," they added.
Two of the 11 investigators reported grants from BASF. The study was funded by the National Institutes of Health, BASF, Pfizer, and DSM Nutritional Products.