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.

Inclusion Criteria:

• Participant in the main CHS study

Exclusion Criteria:

• Not willing to give consent

Cardiovascular Health Study (CHS), is a longitudinal, observational, population-based study of the onset, progression, and course of heart disease and stroke in the elderly which began in 1988. We are only examining those that participated in the the CHS All Stars which is from the same cohort of people who were still alive in 2005 when enrollment began. We approached everyone who was in the CHS study and asked them to participate in the CHS All Stars study. Blood samples were collected at the year 18 visit and analyzed for serum 25(OH)D.