Statistical methods for vitamin D targets for functional outcomes in older adults

老年人功能结果维生素 D 目标的统计方法

• 批准号: 9147536
• 负责人: Jack M Guralnik
• 金额: $ 32.2万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-30 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9147536
• 关键词: 25-hydroxyvitamin D; Activities of Daily Living; Address; Affect; Age; Aging; Alkaline Phosphatase; Award; Biological Markers; Body Composition; Body mass index; Calcium; Clinical; Clinical Research; Clinical Trials; Code; Cohort Studies; Communities; Computer software; Data; Data Set; Diet; Dietary intake; Elderly; Endocrine; Exclusion Criteria; Exposure to; Funding; Gait speed; Genetic; Goals; Health; Heterogeneity; Independent Living; Institute of Medicine (U.S.); Intake; Joints; Language; Lead; Machine Learning; Measures; Mediating; Mediation; Meta-Analysis; Metabolic; Methods; Minerals; Modeling; Observational Study; Outcome; PTH gene; Phosphorus; Physical Function; Public Health; Publications; Published Comment; Publishing; Race; Randomized; Recommendation; Research; Research Personnel; Serum; Societies; Statistical Methods; Structural Models; Subgroup; Sun Exposure; United States National Institutes of Health; Vitamin D; Vitamin D supplementation; Woman; Writing; aging population; bone; bone health; calcium intake; cohort; design; experience; fall risk; falls; fibroblast growth factor 23; flexibility; frailty; functional outcomes; genetic variant; inclusion criteria; indexing; innovation; instrumental activity of daily living; learning strategy; men; muscle strength; novel; osteoporosis with pathological fracture; outcome forecast; prospective; sarcopenia; secondary outcome; sex; skeletal; ultraviolet

 DESCRIPTION (provided by applicant): The concentration of 25-hydroxyvitamin D [25(OH)D] needed for older adults to maintain optimal physical function is unknown. Institute of Medicine and Endocrine Society have publicly debated on 20 ng/mL or 30 ng/mL, respectively, as targets for skeletal health, but both groups agree that stronger evidence is needed to identify target concentrations for extra-skeletal outcomes, e.g., falls and physical function. The problem is significant: >25% of older adults have poor physical function, 50% have 25(OH)D concentrations between 20 and 30 ng/mL. Identifying 25(OH)D targets for older adults will have immediate impact by informing design and analysis of vitamin D supplementation trials. Namely, targets serve as inclusion/exclusion criteria or baseline subgroups and as secondary outcomes. Our solution is to empirically identify and validate sex-specific (possibly stratified by other factors; e.g., race, genetic variants) 25(OH)D targets in older adults (= 65 years) related to lowe risk of falls and better physical function using existing NIH-funded datasets. A critical challenge is that 25(OH)D cannot be randomized; therefore observational data are a crucial part of the solution. Conventional statistical methods are ill-equipped for this problem; thus, we will develop novel statistical methods by adapting and refining structural modeling and machine-learning methods, and apply them to our aims. We will carry out the aims using 4 prospective cohort studies comprising >12,500 older adults: Health, Aging, and Body Composition, Invecchiare in Chianti, Osteoporotic Fractures in Men, and Study of Osteoporotic Fractures. We will: 1) identify and validate 25(OH)D targets for falls reduction, mobility, activities of daily living, and instrumental activities of daily living (functional outcomes); and gait speed, muscle strength, and frailty (proximal conditions) (aim 1); 2) characterize the joint impact of 25(OH)D and serum calcium and phosphorus concentrations on functional outcomes/proximal conditions (aim 2); and 3) quantify mediation of 25(OH)D on functional outcomes/proximal conditions by endocrine and metabolic factors (PTH, serum alkaline phosphatase, aklotho, fibroblast growth factor 23) (aim 3). We will write code in SAS and R statistical languages and disseminate it to the scientific community for use in additional research.