Grant Abstract: Vitamin D Supplements to Prevent Falls in Older Adults: A Dose-Response Trial

Grant Number: 5U01AG047837-02
PI Name: Appel
Project Title: Vitamin D Supplements to Prevent Falls in Older Adults: A Dose-Response Trial

Abstract: Background: Falls are the leading cause of fatal and nonfatal injury among adults aged 65 years and older in the United States. In 2013, 2.5 million older adults were treated for nonfatal falls in hospital emergency departments. When compared to the general aging population, individuals with a history of falls are at heightened risk of lacerations, head trauma, hip fractures, and disability. The underlying mechanisms contributing to this risk are often multifactorial; one factor is vitamin D status. Low vitamin D status in older adults has been associated with reduced muscle mass, strength, and performance, and an increased risk of falls. It has been postulated that both low serum vitamin D status and daily physical activity contribute substantially to the risk of falls but the magnitude and directionality of these associations have not been welldefined. In fact, there is the possibility of a u-shaped relationship between falls and both vitamin D status and physical activity, stimulated in part by trial findings showing that those assigned to a high dose of vitamin D had an increased risk of falls. Recent technological advances in physical activity monitoring (e.g., accelerometers) provide unprecedented opportunities to further our understanding of the quantities, patterns, and trends of daily physical activity associated with falls, and may provide insight into the factors underlying the heightened risk of poor functional status and falls in those with vitamin D deficiency. The STURDY trial (Study To Understand vitamin D and falls Reduction in You), a dose-finding trial of vitamin D supplements (200, 1000, 2000 and 4000IU/d) in ~1,200 adults, 70+ years old (40% black), with low vitamin D status (10 – 25 ng/ml) provides an ideal setting for the proposed ancillary study.
Methods: To define and quantify the dynamics of physical activity and time spent sedentary in older adults, we propose to assess objectively measured physical activity over seven days in ~1,200 STURDY participants at baseline and over 1 year of follow-up.
Objective: The analysis of the data obtained from this research will: (i) explore the dose-response relationship between vitamin D supplements and physical activity, (ii) provide insights into the temporality of the associations among physical activity, serum vitamin D level, and falls, and (iii) provide critical insight into the differences in quantities, patterns, and trends of daily physical activity and functional decline by serum vitamin D level in a large diverse sample of older adults. Accordingly, these data will provide evidence for future public health recommendations aimed at increasing daily physical activity in older populations and curbing threats to falls and disability

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