We thank Lippi et al. (1) for their comment to our recent article (2) examining the cross-sectional relation of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) with metabolic syndrome and its components in a community-dwelling sample of older adults. Although Lippi et al. claim we found no association of 25(OH)D or PTH levels with components of metabolic syndrome, we would like to clarify that in men we did indeed observe dose-response associations of 25(OH)D and PTH with fasting hyperglycemia that were not explained by numerous potential confounders. However, we failed to confirm these findings in women.
In agreement with our results, Lippi et al. report no association of 25(OH)D or PTH levels with the prevalence of hyperglycemia, hypertriglyceridemia, or low HDL concentrations among older women. Taken together, these inconsistent findings highlight the need for well-performed prospective studies to determine what role, if any, 25(OH)D or PTH plays in the development of metabolic syndrome or its components. Optimally, these studies should include individuals residing in areas exposed to varying amounts of direct sunlight to ensure adequate variability in 25(OH)D levels.
