Vitamin D deficiency is a highly prevalent condition, present in approximately 30% to 50% of the general population. A growing body of data suggests that low 25-hydroxyvitamin D levels may adversely affect cardiovascular health. Vitamin D deficiency activates the renin-angiotensin-aldosterone system and can predispose to hypertension and left ventricular hypertrophy. Additionally, vitamin D def...

Although the biological requirement for vitamin D can be met by epidermal exposure to UV light, there are a number of conditions where this production does not occur or is not sufficient to meet biological needs. When this happens, vitamin D must be consumed and is a nutrient. However, two distinct observations have caused researchers to rethink certain dogma in vitamin D biology. First, it app...

BACKGROUND Vitamin D status generally varies seasonally with changing solar UVB radiation, time in the sun, amount of skin exposed, and, possibly, diet. The Seasonal D Study was designed to quantify the amplitude and phase of seasonal variation in the serum concentration of 25-hydroxyvitamin D, (25OH)D)) and identify the determinants of the amplitude and phase and those of inter-individual vari...

A patient is presented who developed hepatic osteodystrophy after orthotopic liver transplantation in association with persistently low serum 25-hydroxyvitamin D levels. After successful liver transplantation there was a delay in the return to normal of the serum 25-hydroxyvitamin D levels until oral supplementation with vitamin D was instituted. This case emphasizes the need for effective trea...

BACKGROUND Although some observational studies have associated higher calcium intake and especially higher vitamin D intake and 25-hydroxyvitamin D levels with lower breast cancer risk, no randomized trial has evaluated these relationships. METHODS Postmenopausal women (N = 36 282) who were enrolled in a Women's Health Initiative clinical trial were randomly assigned to 1000 mg of elemental c...

Vitamin D and parathyroid hormone concentrations were assessed in 31 adults with cystic fibrosis (mean age 24, range 17-52 years), in 28 of whom the bone mineral index in the forearm was also determined. Serum 25-hydroxyvitamin D was subnormal in eight patients, of whom five were receiving vitamin D supplements in standard doses. 1,25-dihydroxyvitamin D and parathyroid hormone concentrations sh...

BACKGROUND The aim of this study was to evaluate the association of maternal serum 25-hydroxyvitamin D, paraoxonase 1, and neutrophil-to-lymphocyte ratio in women having early spontaneous preterm birth without clinical chorioamnionitis. MATERIAL AND METHODS This study was prospectively administered in women referred to our obstetrics service with preterm labor that resulted in preterm birth (n=...

vitamin d is essential for growth and vitamin d deficiency is important issue in adolescent girls as they have a limited rapid growth period .this cross sectional study was done on 167 female students in secondary guidance school in 2006. growth parameters, taking supplementary vitamin d, using sunscreen creams and the type of housing and their avoidance from exposure to sunlight was recorded. ...

Background: Sunlight is the main source of vitamin D; therefore, environmental factors might have an important role in the high prevalence of hypovitaminosis D in children. This study aimed to assess the vitamin D status according to the climate of the living area in a nationally representative sample of Iranian adolescents. Material and Methods: This nationwide cross-sectional survey was perfo...