WAKE FOREST UNIVERSITY
We propose to utilize the requested resources to support additional personnel to perform supplementary research to confirm and expand upon the scientific discoveries expected in the parent grant. The primary goal of this supplement to K01 AG030506 is to obtain serum 25(OH)D measurements in the IDEA Study cohort in order to examine the associations between serum 25(OH)D and physical function among individuals participating in a diet and physical activity trial. The IDEA Study is an ongoing randomized controlled trial contrasting the effect of diet alone, physical activity alone, and diet and physical activity on inflammatory biomarkers and knee joint loads in older, overweight adults with knee osteoarthritis (n=450). As part of the original K01 application, the IDEA Study is being used to replicate the genetic associations found in the LIFE Pilot Study. However, a marker of vitamin D status (serum 25(OH)D) in the IDEA Study was not included in the original application. The overall aim of this Administrative Supplement is to examine the association between vitamin D status, as indicated by circulating 25(OH)D, with muscle strength and physical function in the IDEA Study. We hypothesize that low vitamin D status will be associated with (a) lower levels of muscle strength, physical performance and self-reported physical function at baseline; (b) greater decline in muscle strength, physical performance, and self-reported physical function over follow-up; and (c) less improvement in muscle strength, physical performance, and self-reported physical function in the physical activity intervention arm.