Long-Term Dietary Risk Factor Assessment and Incident AD

描述(由申请者提供)：这项申请建议在现有的双族人群研究芝加哥健康和老龄化项目(CHAP)中，调查长期膳食摄入大量微量营养素和膳食脂肪与阿尔茨海默病发病率和认知能力下降之间的关系的假设。这组研究人员和其他研究人员最近的发现表明，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具有保护作用。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，我们发现抗氧化剂营养素的摄入量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量、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不清楚或略有意义。CHAP研究提供了许多基本要素来检验这些饮食假设，包括前瞻性设计、有效的饮食评估工具、用于无偏见病例检测的结构化临床评估，以及对6000多人长达15年的认知变化数据。然而，由于正在进行的CHAP研究正在大幅扩大，以包括新的符合年龄条件的队列，因为原始队列的规模因死亡率而减少，而且现有的唯一饮食数据处于原始队列的基线，因此目前不可能利用扩大后的研究的统计能力增加和更长时间的后续行动。因此，为了解释长期随访期间饮食摄入量的个体内差异，并最终检验这些新的和令人兴奋的饮食假说，拟议的研究将：1)在整个CHAP研究社区进行重复的饮食评估，以准确测量长期摄入量；2)对银行血样进行生化分析，以检测血浆同型半胱氨酸浓度。拟议的应用应有助于回答有关饮食预防一种影响到大量老年人的衰弱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.