Down syndrome and dementia: A randomized, controlled trial of antioxidant supplementation
What this study found
Antioxidant supplementation was safe and well tolerated, but it did not improve or stabilize cognitive function compared with placebo over 2 years. The primary cognitive outcome, DMR SOC, was null (slope 0.34 points per 1/2-year; 95% CI -1.39 to 2.07; P = 0.70), with no benefit at 1 year (difference 1.69; 95% CI -2.92 to 6.31; P = 0.47) or 2 years (difference 3.71; 95% CI -4.81 to 12.22; P = 0.39). SIB was also null at 1 year (difference -9.08; 95% CI -23.86 to 5.70; P = 0.23) and 2 years (difference -1.51; 95% CI -13.65 to 10.63; P = 0.81). Most secondary measures were similarly not…
- Study & population
- Randomized, placebo-controlled trial in adults with Down syndrome and Alzheimer-type dementia receiving standard dementia care at two ambulatory clinic sites in California.
- Intervention
- Oral antioxidant combination: 900 IU alpha-tocopherol, 200 mg ascorbic acid, and 600 mg alpha-lipoic acid daily for 2 years, taken as one capsule at breakfast and two capsules with the evening meal.
- Key limitation
- Small active-arm sample and substantial attrition over time limited power, with only 23 participants evaluated at year 1 and 16 at year 2.
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Open PDFOriginal abstract
Individuals with Down syndrome over age 40 years are at risk for developing dementia of the Alzheimer type and have evidence for chronic oxidative stress. There is a paucity of treatment trials for dementia in Down syndrome in comparison to Alzheimer disease in the general (non‐Down syndrome) population. This 2‐year randomized, double‐blind, placebo‐controlled trial assessed whether daily oral antioxidant supplementation (900 IU of alpha‐tocopherol, 200 mg of ascorbic acid and 600 mg of alpha‐lipoic acid) was effective, safe and tolerable for 53 individuals with Down syndrome and dementia. The outcome measures comprised a battery of neuropsychological assessments administered at baseline and every 6 months. Compared to the placebo group, those individuals receiving the antioxidant supplement showed neither an improvement in cognitive functioning nor a stabilization of cognitive decline. Mean plasma levels of alpha‐tocopherol increased ∼2‐fold in the treatment group and were consistently higher than the placebo group over the treatment period. Pill counts indicated good compliance with the regimen. No serious adverse events attributed to the treatment were noted. We conclude that antioxidant supplementation is safe, though ineffective as a treatment for dementia in individuals with Down syndrome and Alzheimer type dementia. Our findings are similar to studies of antioxidant supplementation in Alzheimer disease in the general population. The feasibility of carrying out a clinical trial for dementia in Down syndrome is demonstrated. © 2011 Wiley‐Liss, Inc.