BACKGROUND Inadequate photosynthesis or oral intake of Vitamin D are associated with high incidence rates of colorectal cancer, but the dose-response relationship has not been adequately studied. METHODS Dose-response gradients from observational studies of Vitamin D intake and serum 25-hydroxyvitamin D were plotted as trend lines. The point on each linear trend line corresponding to an odds ...

BACKGROUND Although environmental factors, mainly nutrition and UV-B radiation, have been considered major determinants of vitamin D status, they have only explained a modest proportion of the variation in serum 25-hydroxyvitamin D. We aimed to study the seasonal impact of genetic factors on serum 25-hydroxyvitamin D concentrations. METHODOLOGY/PRINCIPAL FINDINGS 204 same-sex twins, aged 39-8...

OBJECTIVE To evaluate whether vitamin D is associated with multiple sclerosis (MS) status and disease severity in African Americans. METHODS Serum 25-hydroxyvitamin D was compared in a cross-sectional sample of 339 African Americans with MS and 342 African American controls. Correlations between disease severity (Multiple Sclerosis Severity Score [MSSS]) and 25-hydroxyvitamin D levels were so...

In their article in the current issue of Clinical Chemistry, Farrell et al. (1 ) describe the latest in a number of studies (2, 3 ) highlighting the method-related variability in serum 25-hydroxyvitamin D (25-OHD) results. There is common agreement that 25-OHD is a “difficult” analyte. That quality is generally ascribed to its hydrophobic nature, its existence in several different molecular for...

BACKGROUND We previously demonstrated that 25-hydroxyvitamin D(3) concentrations in gingival crevicular fluid are 300 times higher than those in the plasma of patients with aggressive periodontitis. Here we explored whether 25-hydroxyvitamin D(3) can be synthesized by periodontal soft tissue cells. We also investigated which of the two main kinds of hydroxylases, CYP27A1 and CYP2R1, is the key ...

BACKGROUND Sub-optimal levels of vitamin D have been found to be highly prevalent in all age groups, with epidemiologic studies demonstrating a link between vitamin D deficiency and disease susceptibility, such as infection and cancer, and mortality rates. In adult transplant patients, it has been suggested that the immunomodulatory properties of vitamin D may have an important role in the prev...