Vitamin D and Physical Function in Older Adults
Projections from NHANES III indicate that approximately 12,000,000 U.S. adults ≥ 60 years of age have vitamin D insufficiency (serum 25(OH)D < 50 nmol/L). A growing body of evidence suggests that vitamin D status may be important in biologic processes involved in the maintenance of physical function. To test the hypothesis that vitamin D insufficiency is associated with poorer muscle strength and physical performance, we propose to evaluate the role of vitamin D status (serum 25(OH)D) on physical function and falls in the CHS All Stars cohort, a population of advanced age. The specific aims are as follows:
Specific Aim 1. To describe the prevalence and correlates of vitamin D insufficiency in adults of advanced age.
Specific Aim 2. To examine the cross-sectional association between vitamin D status and muscle strength (leg and grip strength), physical performance (3 m/15 ft walk time, repeated chair stands, and standing balance), self-reported physical function (mobility, ADL and IADL disability), and falls.
Specific Aim 3. To examine the longitudinal association between vitamin D status at baseline and incident disability (mobility, ADL and IADL disability) over 3 years of follow-up.
Research Hypotheses: Low vitamin D status (25(OH)D < 50 nmol/L) will be associated with (a) lower levels of muscle strength and physical performance; (b) higher levels of self-reported limitations in physical function and falls; and (c) greater odds of incident disability.
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||Role of Vitamin D Status on Physical Function and Falls in Adults of Advanced Age|
- To examine the association between vitamin D status and muscle strength (leg, grip strength), physical performance (3m/15 ft walk time, repeated chair stands, and balance), self-reported physical function (mobility, ADL and IADL disability), and falls. [ Time Frame: At the year 18 visit of the CHS study ]
- To examine the longitudinal association between vitamin D status at baseline and incident disability (mobility, ADL and IADL disability) over 3 years of follow-up. [ Time Frame: Years 18 - 21 of CHS Study ]
- To describe the prevalence and correlates of vitamin D insufficiency in adults of advanced age. [ Time Frame: Year 18 of CHS study ]
|Study Start Date:||April 2008|
|Study Completion Date:||February 2011|
|Primary Completion Date:||February 2011 (Final data collection date for primary outcome measure)|
CHS All Stars
CHS All Stars is an ancillary study of the Cardiovascular Health Study (CHS), a longitudinal, observational, population-based study of the onset, progression, and course of heart disease and stroke in the elderly which began in 1988. The All Stars study reexamined the survivors of CHS to determine the likelihood of maintaining function later in life. A focus was to determine whether age-related biological factors are long-term predicators of functional aging which was assessed through a follow-up exam (Yr 18 visit conducted in 2005-06, n=1674 older adults, mean age =84 years) and 3 yrs of subsequent 6 month interval phone contacts. Vitamin D status (serum 25(OH)D and PTH) is being assessed in all CHS All Stars participants who provided a blood sample at the Yr 18 visit (n~1100).
Please refer to this study by its ClinicalTrials.gov identifier: NCT00710957
|Principal Investigator:||Denise Houston, PhD||Wake Forest University Health Sciences|