In type 2 diabetic patients, the relationships between 25-hydroxyvitamin D and parathyroid hormone levels, and glycemic control, remain unclear. We evaluated associations between 25-hydroxyvitamin D, parathyroid hormone, and hemoglobin A1c levels after adjusting for other covariates, including log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels, in Korean p...

CONTEXT Few studies in subjects over 50 yr of age have evaluated the influence of variable doses of vitamin D supplementation on serum 25-hydroxyvitamin D levels. OBJECTIVE We performed a meta-analysis of changes in circulating 25-hydroxyvitamin D level associated with vitamin D supplementation in Caucasian subjects over 50 yr old. DATA SOURCES We conducted a systematic search in literature...

 ABSTRACT Background: To determine daily calcium, Vitamin D intake and serum biochemical findings of rickets in adolescent girls. Methods: A total of 414 healthy adolescent student girls aged 11-15 years were evaluated from various areas of Tehran, Iran with different socioeconomic status. A randomized, cross-sectional, prospective and descriptive study was undertaken for calculation of daily c...

BACKGROUND Vitamin D deficiency is associated with a range of systemic diseases including ocular disorders. The objective of this study is to measure tear vitamin D levels and investigate the correlation between serum and tear vitamin D levels. METHODS A total of 48 healthy volunteers without any systemic and ocular disease were recruited for this observational cohort study. Serum was collect...

Hip fracture has increasingly become a social and economic burden. The relationship between serum 25-hydroxyvitamin D levels and the risk of hip fracture reported by previous studies remains controversial. We searched Pubmed and Embase to identify studies reporting the relationship between serum 25-hydroxyvitamin D levels and risk of hip fracture. Fifteen prospective cohort studies with a total...

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...

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 ...

vitamin d deficiency is the most under-diagnosed medical condition in postmenopausal women. there are few epidemiologic studies on vitamin d status of postmenopausal women in iran. this study aimed to investigate the 25-hydroxyvitamin d levels in postmenopausal women living in tehran, capital of iran. in this cross sectional study, 110 women were selected via convenience sampling method from me...

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...

I describe a new assay that is capable of measuring vitamin D2, vitamin D3, 25-hydroxyvitamin D2, and 25-hydroxyvitamin D3 in 2 ml of plasma or serum. Plasma is extracted by the Bligh and Dyer technique [Can. J. Biochem. Physiol. 37, 911 (1959)], the lipid component is fractionated by two high-performance liquid-chromatographic systems based upon adsorption and reversed-phase chromatography, an...