Defining the Optimal Target Population for Trials of Polyunsaturated Fatty Acid Supplementation Using the Erythrocyte Omega-3 Index: A Step Towards Personalized Prevention of Cognitive Decline?

• Published in: The Journal of nutrition, health & aging health & aging, 2018-10, Vol.22 (8), p.982-988
• Main Authors: Coley, Nicola, Raman, R., Donohue, M. C., Aisen, P. S., Vellas, B., Andrieu, S.
• Format: Article
• Language: English
• Subjects: Activities of Daily Living; Aged; Aging; Cognition - physiology; Cognitive Dysfunction - drug therapy; Cognitive Dysfunction - prevention & control; Dementia; Dementia - physiopathology; Dietary Supplements; Docosahexaenoic Acids - therapeutic use; Eicosapentaenoic Acid - analogs & derivatives; Eicosapentaenoic Acid - therapeutic use; Erythrocytes - chemistry; Fatty acids; Fatty Acids, Omega-3 - analysis; Female; Geriatrics/Gerontology; Humans; Male; Medicine; Medicine & Public Health; Memory; Neurosciences; Nutrition; Placebos - administration & dosage; Polyunsaturated fatty acids; Primary Care Medicine; Quality of Life Research; Retrospective Studies; Walking Speed - physiology
• ISSN: 1279-7707; 1760-4788
• DOI: 10.1007/s12603-018-1052-2

Objectives to identify the optimal erythrocyte omega-3 index cut-off for predicting cognitive decline and/or polyunsaturated fatty acid (PUFA) treatment response, in order to better define the target population for future dementia prevention trials. Design & Setting Secondary exploratory analysis of the randomized controlled MAPT prevention trial. Participants 724 dementia-free subjects aged 70 or older with subjective memory complaints, limitations in one instrumental activity of daily living, and/or slow gait speed. Intervention 800mg docosahexaenoic acid (DHA) and 225mg eicosapentaenoic acid (EPA) daily versus placebo. Measurements Erythrocyte omega-3 index was measured at baseline. Cognition was measured over 3 years with a composite cognitive score (mean of 4 z-scores). Results Placebo group subjects in the lowest quartile of baseline erythrocyte omega-3 index (i.e. ≤4.83%) underwent significantly more 3-year cognitive decline than the other quartiles (mean composite score difference 0.14, 95%CI [0.00, 0.28], p=0.048). In a ROC curve analysis, the optimal omega-3 index cut-off for predicting notable cognitive decline was 5.3%. There was a consistent but non-significant difference in 3-year cognitive decline of approximately 0.12 points between PUFA-treated and placebo subjects with “low” baseline omega-3 index when the cut-off was set at ≤5.27%. Conclusions Dementia-free older adults with an omega-3 index below approximately 5% are at increased risk of cognitive decline, and could be a good target population for testing the cognitive effects of PUFA supplementation.