We are writing to respond to the letter sent by Drs. Truong and Shil concerning the effect of vitamin D on inflammation in our recently published article (1). While we do agree with their assessment that there is literature to suggest a role for vitamin D in the inflammatory cascade and in skeletal muscle function, owing to the randomized nature of this study design, such confounders should, in theory, be balanced between groups. A post hoc assessment of 25-hydroxyvitamin D (25-OH-D) between groups reveals no difference in baseline levels, with the physical activity group reporting 50.43 + 185 nmol.L~(-1) and the successful aging group reporting 54.09 + 275 nmol.L~(-1)(P = 0.17). Further, inclusion of 25-OH-D in our primary statistical model did not alter the relationship between the intervention arm and the status of inflammatory biomarkers. Regardless, the purpose of these analyses was to assess the effect of long-term physical activity on inflammatory biomarkers in older adults; therefore, the observation that vitamin D is related to inflammation and skeletal muscle strength does not detract from the main study findings (1,2).
展开▼
