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Errors in Diet Assessment: Impact on Diet-Cancer trials

饮食评估中的错误：对饮食癌症试验的影响

基本信息

批准号：
7226987
负责人：
Loki Natarajan
金额：
$ 7.5万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-05-01 至 2009-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7226987
关键词：
Accounting Advocate Age Appendix Area Arizona Attenuated Behavior Biological Markers Blood specimen Body Size Cancer Etiology Carotenoids Cessation of life Characteristics Clinical Trials Cohort Studies Computer software Consensus Data Diet Dietary Assessment Dietary Intervention Dietary intake Disease Eating Ethnic Origin Evaluation Exhibits Fat-Restricted Diet Fiber Food Frequencies Future Goals Hour Incidence Intake Intervention Intervention Studies Intervention Trial Interview Investigation Lead Life Life Style Longitudinal Studies Malignant Neoplasms Measurement Measures Methods Modeling Nature Nutritional Odds Ratio Outcome Participant Patient Self-Report Patients Physical activity Plasma Questionnaires Randomized Randomized Controlled Clinical Trials Reporting Research Research Personnel Role Sampling Staging Standards of Weights and Measures Statistical Methods Statistical Models Time Uncertainty Validity and Reliability Variant Woman Work cancer diagnosis cancer recurrence comparison group design diet and cancer fruits and vegetables improved instrument malignant breast neoplasm response simulation size survivorship tool

项目摘要

DESCRIPTION (provided by applicant): Project Summary: Over 500,000 cancer deaths are expected to occur in the US in 2005. Investigations of the impact of diet on cancer have been mixed. Errors in dietary assessment methods lead to biased estimates of the effect of diet on cancer outcomes, a possible explanation for the lack of consensus of diet-cancer studies. The goal of this proposal is to quantify bias, reliability and validity of dietary assessment methods using existing data from a longitudinal dietary intervention study. The validity coefficients estimated in this proposal will provide statistical adjustment factors that can be used to obtain corrected estimates of diet-cancer associations. The implications of bias in dietary assessment methods for the design of cancer trials will also be examined. The analysis will focus on the ongoing Women's Healthy Eating and Living (WHEL) study, a randomized trial examining the effect of a high fruit, vegetable, fiber and low-fat diet on breast cancer recurrence. The study randomized 3088 women between 1995 and 2000, and will close in 2007. The dietary exposure of WHEL subjects is assessed at study entry, 1 and 4 yrs by 3 methods: repeat 24-hour recall interviews; the Arizona Food Frequency Questionnaire; blood samples analyzed for plasma carotenoid concentrations (a marker, well correlated with fruit/vegetable intake). The specific aims of this proposal are (1) To assess the reliability of the plasma marker over time (2a) To develop models for estimating bias and measurement error in self-report dietary instruments (2b) To assess whether participating in a diet intervention reduces bias (2c) To examine what factors (eg age, body-size) contribute to bias/error (3) To develop (and make publicly available) software implementing statistical methods derived in this proposal. Aim 1 will estimate reliability measures (intraclass correlation, within-subject coefficient of variation) for the plasma marker. For Aim 2, mixed-effects models will be fit with flexible distributions for "true" (unobservable) dietary intake (eg mixture of normals). Simulations will be used to investigate the robustness of our findings. Relevance: Lifestyle factors such as diet and physical activity are modifiable behaviors that could protect against cancer incidence and improve survivorship after a cancer diagnosis. Statistical methods that quantify biases in dietary assessment tools and correct these biases could lead to more valid estimates of diet-cancer associations.

描述(由申请人提供)：项目摘要：预计2005年美国将有超过50万人死于癌症。关于饮食对癌症的影响的研究一直是喜忧参半。饮食评估方法的错误导致了对饮食对癌症结果影响的有偏见的估计，这可能是饮食-癌症研究缺乏共识的一个原因。这项建议的目标是利用一项纵向饮食干预研究的现有数据来量化饮食评估方法的偏倚、可靠性和有效性。本提案中估计的有效性系数将提供统计调整系数，可用于获得饮食与癌症相关性的正确估计。此外，还将研究饮食评估方法中的偏差对癌症试验设计的影响。这项分析将集中在正在进行的女性健康饮食和生活研究(WHEL)上，这是一项随机试验，旨在研究高水果、蔬菜、纤维和低脂肪饮食对乳腺癌复发的影响。这项研究在1995年至2000年间随机抽查了3088名女性，并将于2007年结束。WHEL受试者的膳食暴露在研究开始时、1年和4年通过3种方法进行评估：重复24小时回忆访谈；亚利桑那州食物频率问卷；血液样本分析血浆类胡萝卜素浓度(一种标记，与水果/蔬菜摄入量很好地相关)。这项建议的具体目的是(1)评估血浆标记物随时间的可靠性(2a)开发用于估计自我报告膳食工具中的偏差和测量误差的模型(2b)评估参与饮食干预是否减少偏差(2c)检查哪些因素(例如年龄、体型)导致偏差/误差(3)开发(并公开提供)实施本建议中所推导的统计方法的软件。目标1将评估血浆标记物的可靠性指标(组内相关性、受试者内变异系数)。对于目标2，混合效应模型将适用于“真实的”(不可观察的)膳食摄入量的灵活分布(例如，正常人群的混合)。模拟将被用来调查我们发现的稳健性。相关性：饮食和体力活动等生活方式因素是可以改变的行为，可以预防癌症的发生并提高癌症诊断后的存活率。量化饮食评估工具中的偏差并纠正这些偏差的统计方法可能会导致对饮食与癌症相关性的更有效估计。