SAN DIEGO — Among older patients with mild cognitive impairment (MCI), the combination of vitamin D and physical exercise plus cognitive training led to greater improvements than exercise alone. The findings were drawn from an unusual study design that split patients into five groups, one of which included both interventions.
After the study was completed, researchers collapsed the groups into a single analysis to compare the different regimens, according to Manuel Montero-Odasso, MD, PhD, who presented the work at the Alzheimer’s Association International Conference. He is a geriatrician at Parkwood Institute, London, Ont.
Two previous trials looked at whether the combination of exercise plus cognitive training could outperform either intervention alone. In both, the combination improved cognition but not as much as either intervention alone. “So it seemed that when they combine it, they didn’t do as well,” said Montero-Odasso. Those findings left doubt about whether or not there is synergism between the two approaches.
Sequential, Not Simultaneous
A possible explanation for the finding is that patients who are doing both cognitive training and physical exercise simultaneously might not be able to focus enough on either task to do get the maximum benefit. “When we try to combine concurrently, participants or patients cannot focus and do enough progression in both at the same time. That’s the reason we designed the trial in a way that the interventions were sequential. You got a very good quality (cognitive) training, and later you got the exercise,” said Montero-Odasso.
In the new study, patients receiving both interventions conducted the cognitive training first, then did physical exercises 30 minutes later. “The practical message is that you should follow a program. Something I see in my patients, when they do the two things at the same time, they don’t pay enough attention,” said Montero-Odasso.
The researchers added vitamin D to the regimen as there have been small studies reporting that vitamin D supplementation can lead to greater muscle mass resulting from exercise.
The study included 176 patients aged 60-85 with MCI. The researchers excluded patients already participating in an active exercise program with a personal trainer, as well as those taking vitamin D at doses higher than 1,000 IU/day.
Over 20 weeks, the randomized groups included combination exercise and cognitive training with vitamin D (10,000 IU three times per week), exercise and cognitive training with placebo, exercise with a cognitive control and vitamin D, exercise with a cognitive control and placebo, and an exercise control (balance and toning) with cognitive control and placebo.
The interventions were completed three times per week. Cognitive training employed a tablet with multifunctional tasks and memory components. It was adaptive, becoming more difficult as patients improved or simplifying the task if a patient struggled. The exercise component included 40 minutes of progressive, supervised resistance training, followed by 20 minutes of aerobic exercise.
Compared with the double-placebo group, the double-intervention group had significant improvement in cognitive performance. “Exercise alone without cognitive training shows an effect, but that effect was lower than a combination with cognitive training,” said Montero-Odasso.
The combined groups had medium effect sizes on cognition when combined with vitamin D (Cohen’s d, 0.65; P = .003) and with vitamin D placebo (Cohen’s d, 0.58; P = .013). There were nonsignificant improvements in the exercise and vitamin D group (Cohen’s d, 0.30; P = .241) and the exercise plus placebo group (Cohen’s d, 0.42; P = .139)
After collapsing the arms, the researchers found that the exercise plus cognitive training regimen had an effect size of 0.62 (P = .002), while exercise alone only trended toward improvement and with a small effect size (Cohen’s d, 0.36; P = .13). There was no apparent effect of vitamin D supplementation, though Montero-Odasso pointed out that most participants were taking vitamin D supplements before study entry and had normal to high serum levels of vitamin D.
The study was limited by an inability to retain patients due to the COVID-19 pandemic, leading to a dropout rate of 17%.
“I think the idea of combining risk reduction strategies together in a population and individuals with MCI is really exciting. These are optimistic results. You certainly need to look into a larger and more diverse population as it goes forward,” said Heather Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, who was asked to comment on the study.
She noted that the study looked at all-cause cognitive impairment. It would be interesting, Snyder said, to see how individuals with different underlying conditions handle the combination intervention.
The researchers are now in the planning stage of the Synergic 2 trial, which will incorporate exercise and cognitive training, plus diet and sleep counseling. It will be conducted virtually, involving one-to-one interactions with coaches.
Montero-Odasso and Snyder have no relevant financial disclosures.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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