Long-Term Dietary Risk Factor Assessment and Incident AD

描述（由申请人提供）：本申请旨在调查芝加哥健康与老龄化项目（CHAP）现有的一项混血儿人口研究中，长期膳食摄入一些微量营养素和膳食脂肪与阿尔茨海默病和认知能力下降之间的关系。这组研究人员和其他人最近的发现表明，饮食中摄入叶酸、维生素B-12和维生素B-6可能对阿尔茨海默病的发生有保护作用。其他人提出，这些微量营养素的保护机制可能是通过减少同型半胱氨酸的积累。此外，我们发现抗氧化营养素的摄入和膳食脂肪组成在阿尔茨海默病的发展中可能很重要，尽管多不饱和脂肪和单不饱和脂肪的摄入、n-3脂肪酸、α -亚麻酸和二十碳五烯酸、维生素C和维生素E补充剂的使用之间的关系尚不清楚或意义不大。CHAP研究为验证这些饮食假设提供了许多基本要素，包括前瞻性设计、经过验证的饮食评估工具、用于无偏病例检测的结构化临床评估，以及超过6000人的长达15年的认知变化数据。然而，由于正在进行的CHAP研究被大大扩展到包括新的符合年龄的队列，因为原始队列的规模由于死亡率而减少，并且唯一现有的饮食数据是原始队列的基线数据，因此目前不可能利用扩大研究的统计能力增加和随访时间延长的优势。因此，为了解释长期随访期间饮食摄入的个体差异，并最终验证这些新的和令人兴奋的饮食假设，拟议的研究将：1)在整个CHAP研究群体中进行重复的饮食评估，以准确测量长期摄入量；2)对储存的血液样本进行血浆同型半胱氨酸浓度的生化分析。拟议的应用程序应有助于回答有关饮食预防影响大量老年人的使人衰弱的疾病的重要科学问题。

DESCRIPTION (provided by applicant): This application proposes to investigate hypotheses on the associations of long-term dietary intake of a number of micro nutrients and dietary fats with incident Alzheimer's disease and cognitive decline in an existing biracial population study, the Chicago Health and Aging Project (CHAP). Recent findings by this group of investigators and others suggest that dietary intake of folate, vitamin B-12, and vitamin B-6 may be protective against incident Alzheimer's disease. Others propose that the mechanism for protection by these micronutrients may be through reduction in the accumulation of homocysteine. In addition, we found that intake of antioxidant nutrients and dietary fat composition may be important in the development of Alzheimer's disease, although associations for intakes of polyunsaturated and monounsaturated fats, the n-3 fatty acids, alpha-linolenic acid and eicosapentaenoic acid, vitamin C, and vitamin E supplement use were unclear or marginally significant. The CHAP study provides many essential elements to test these dietary hypotheses including, a prospective design, a validated dietary assessment tool, structured clinical evaluation for unbiased case detection, and up to 15 years of cognitive change data on more than 6,000 persons. However, because the ongoing CHAP study is being greatly expanded to include newly age-eligible cohorts as the original cohort decreases in size due to mortality, and the only existing dietary data is at baseline on the original cohort, it is not currently possible to take advantage of the increased statistical power and longer follow-up of the expanded study. Therefore, in order to account for intraindividual variation in dietary intake over the long follow-up period, and to test conclusively these new and exciting dietary hypotheses, the proposed study will: 1) conduct repeated dietary assessments in the entire CHAP study community to accurately measure long-term intake, and 2) conduct biochemical analyses of banked blood samples for plasma homocysteine concentration. The proposed application should help to answer important scientific questions on the dietary prevention of a debilitating disease that affects a large number of older persons.