Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, Or Other Nutrient
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Age-Related Eye Disease Study II (AREDS II): A Multi-center, Randomized Trial of Lutein, Zeaxanthin, and Long-Chain Omega- 3 Fatty Acids (Docosahexaenoic Acid [DHA] and Eicosapentaenoic Acid [EPA]) in Age-Related Macular Degeneration COGNITIVE FUNCTION STUDY PROTOCOL Version 1: May 16, 2006 Downloaded From: https://jamanetwork.com/ on 10/02/2021 AREDS II Cognitive Function Study Protocol - Version 1 – May 16, 2006 TABLE OF CONTENTS 1.0 Background and Rationale ................................................................................... 2 2.0 Study Objectives................................................................................................... 3 3.0 AREDS II Cognitive Function Battery ................................................................... 4 3.1 Description of AREDS II Telephone Battery................................................. 4 4.0 Eligibility Criteria ................................................................................................... 5 5.0 Implementation ..................................................................................................... 5 5.1 Protocol Development.................................................................................. 6 5.2 Training and Certification ............................................................................. 6 5.3 Cognitive Function Testing........................................................................... 6 6.0 Statistical Considerations ..................................................................................... 7 6.1 Overview ...................................................................................................... 7 6.2 Sample Size and Power............................................................................... 7 6.3 Statistical Methods....................................................................................... 8 7.0 Data Management ................................................................................................ 8 8.0 Access to Source Documents/Monitoring of the Study......................................... 9 9.0 Quality Control and Assurance ............................................................................. 9 10.0 Ethics....................................................................................................................9 10.1 Institutional Review Board............................................................................ 9 10.2 Informed Consent Process......................................................................... 10 10.3 Protocol Modifications ................................................................................ 10 11.0 References ......................................................................................................... 11 -2- Downloaded From: https://jamanetwork.com/ on 10/02/2021 AREDS II Cognitive Function Study Protocol - Version 1 May 16, 2006 COGNITIVE FUNCTION STUDY 1.0 BACKGROUND AND RATIONALE Cognitive impairment, or an acquired deficit in memory function, problem solving, orientation, or abstraction, reduces an individual’s ability to function independently and is a major component of age-related deterioration. Several studies have shown that cognitive deterioration in the elderly can be caused or worsened by nutritional deficiencies. However, for normally aging older adults, limited information is available on the associations between nutrition and cognition. AREDS II participants will be asked to take part in a study testing cognitive function. The battery of tests selected by experts in the field will take approximately 30 minutes to administer. The purpose of this study is to measure the potential beneficial or deleterious effect of the AREDS II study supplements on cognitive function and to investigate potential associations between cognitive function and age-related macular degeneration (AMD) development and progression. AREDS II is a multi-center Phase III randomized clinical trial designed to assess the effects of oral supplementation of high doses of macular xanthophylls (lutein and zeaxanthin) and/or omega-3 long-chain polyunsaturated fatty acids (LCPUFAs) as a treatment for AMD, cataract and moderate vision loss. In addition to this objective, the study will provide information on the clinical course, prognosis, and risk factors for development and progression of both AMD and cataract. Other study goals include the evaluation of eliminating beta-carotene and/or reducing zinc in the original AREDS formulation on the progression and development of AMD. AREDS II will also seek to validate the fundus photographic AMD scale developed from AREDS. Cognitive impairment and Alzheimer's disease have a significant negative impact on quality of life of elderly individuals and their families as the ability to function independently is progressively and usually irreversibly affected. Since the number of elderly individuals in industrialized countries continues to dramatically increase, maintaining cognitive function and preventing Alzheimer's disease and other dementias are a major public health priority in enhancing the ability of this rapidly growing population segment to live independently. Recent research studies have investigated the association between nutritional status and cognitive function and incidence of dementia as well as the beneficial effects of nutritional supplementation on incidence and progression of Alzheimer's disease and other types of dementia. Oxidative pathways are thought to be involved in the etiology of both Alzheimer’s disease (AD) and vascular dementia, the two most common forms of dementia. Researchers hypothesize that the accumulation of oxygen free-radicals and other reactive oxygen species leads to neuronal degeneration and cell death.1-2 Furthermore, in-vitro studies have reported that antioxidants prevent oxidative damage.3-4 Although some observational studies of non-demented older adults have suggested that high antioxidant dietary intake or the use of antioxidant supplements is associated with better cognitive performance, 5-8 other studies have reported no protective effect. 9-12 Omega-3 fatty acids are particularly -3- Downloaded From: https://jamanetwork.com/ on 10/02/2021 AREDS II Cognitive Function Study Protocol - Version 1 – May 16, 2006 important for the health of the brain. Docosahexaenoic acid (DHA) is an essential structural component of brain cells, where it is the most prominent. Low levels of DHA have been found in Alzheimer’s patients,13 and increasingly, this fatty acid is shown to be important for mental health in adults. A recent study found low levels of omega-3 fatty acids in the blood were linked to greater cognitive decline in the elderly. A few studies have been inconclusive regarding the relationship between cognitive and visual impairment.14-16 Visual impairment was found to be associated with both an increased risk and an increased clinical severity of Alzheimer’s disease in a case control study of 87 patients greater than or equal to 65 years of age with mild to moderate, clinically diagnosed Alzheimer’s disease and 87 non demented controls matched to the cases by age, gender and education.17 Rizzo et al found a correlation between impairments of visual function and overall severity of cognitive impairment in AD.18 A study of 156 elderly individuals from the Berlin Aging Study found an association between visual impairment and poor performance on intelligence tests covering five cognitive domains.19 The Australian Longitudinal Study of Aging found that a two-year decline in vision was associated with memory decline in an elderly population.20 A large study of women aged 69 and older participating in the Study of Osteoporotic Fractures found a twofold increase in the odds of cognitive and functional decline over time associated with vision impairment (best corrected vision worse than 20/40).21 A cohort study of community-dwelling older Mexican Americans found that near vision impairment was associated with low cognitive function along with cognitive decline over a 7-year period.22 This association remained significant after adjustment for possible confounders. A cognitive function study was added to the Age-Related Eye Disease Study (AREDS) near the conclusion of the clinical trial portion of the study. Data from AREDS suggested a possible association between advanced AMD and visual acuity with cognitive impairment in older persons.23 The AREDS results indicated that when compared to placebo treatment, antioxidants with or without zinc and copper did not have a statistically significant effect on cognitive performance at the end of the trial. 24 A limitation of the AREDS results, however, is that cognitive testing was not implemented at baseline, thus leaving the researchers unable to determine whether antioxidant or copper and zinc treatment influences the rate of cognitive decline. Investigations of dietary supplementation on cognition have been criticized for being of short duration, having small sample sizes, and assessing nonstandardized doses. AREDS II provides an opportunity to counter these criticisms and investigate the potential associations between cognitive function and supplementation with lutein/zeaxanthin and/or long-chain omega-3 fatty acids and with age-related macular degeneration. 2.0 STUDY OBJECTIVES 2.1 To measure the potential differences in effect of scores of participants by randomized AREDS II Study Supplement assignment. -4- Downloaded From: https://jamanetwork.com/