Vitamin D

BACKGROUND: Vitamin D deficiency has been associated with adverse health outcomes. PURPOSE: To systematically review benefits and harms of vitamin D screening in asymptomatic adults. DATA SOURCES: Ovid MEDLINE (through the third week of August 2014), Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews. STUDY SELECTION: Randomized trials of screening for and treatment of vitamin D deficiency and case-control studies nested within the Women's Health Initiative...

BACKGROUND: Despite the essential role of vitamin D in muscle function, the prevalence of vitamin D deficiency has been reported to be very high. Recently, low vitamin D level was found to correlate with fatty degeneration of the rotator cuff tendon in humans and to negatively affect early healing at the rotator cuff repair site in an animal study. However, the effects of vitamin D level on severity of rotator cuff tear and healing after surgical repair have not been documented. PURPOSE: To evaluate (1) the prevalence of vitamin D deficiency among patients who underwent arthroscopic repair for a full-thickness rotator cuff tear, (2) the relationship of vitamin D level with severity of the rotator cuff tear, and (3) surgical outcomes after repair...

INTRODUCTION: We studied prevalence of hypovitaminosis D, its determinants, and whether achievement of recommended dietary vitamin D intake (10 μg/d) is associated with absence of hypovitaminosis D in adults. METHODS: The study is part of the Cardiovascular Risk in Young Finns Study. We collected serum samples of 25-hydroxyvitamin D as part of the 27-year follow-up (994 men and 1,210 women aged 30-45 years). Hypovitaminosis was defined as vitamin D concentration ≤ 50 nmol/L...

Hypovitaminosis D is prevalent worldwide but proportions vary widely between regions, depending on genetic and lifestyle factors, the threshold to define deficiency, and accuracy of 25-hydroxyvitamin D (25OHD) assays used. Latitude, pollution, concealing clothing, sun exposure, gender, dietary habits, and lack of government regulation account for up to 50% in variations in serum 25OHD levels, whereas genetic polymorphisms in the vitamin D pathway account for less than 5%. Organizations/societies have developed guidelines for recommended desirable 25OHD levels and vitamin D doses to reach them, but their applicability across age groups and populations are still debated...

OBJECTIVE: Low vitamin D levels predict the development of diabetes. This double-blind, randomized, control study in subjects with prediabetes and hypovitaminosis D evaluated whether high doses of vitamin D for 1 year affected insulin secretion, insulin sensitivity, and the development of diabetes. RESEARCH DESIGN AND METHODS: A total of 1,551 subjects ≥40 years of age not known to have diabetes were screened with A1C levels. Subjects with A1C levels of 5...

BACKGROUND: A large body of epidemiological and experimental evidence suggests that vitamin D deficiency may promote hypertension. This raises the possibility that vitamin D supplementation could be a simple intervention to reduce blood pressure, but data from prospective, randomized trials are limited. METHODS AND RESULTS: A double-blind, randomized, controlled trial was conducted at 4 sites in the United States. We enrolled 534 individuals 18 to 50 years of age with low vitamin D status (25-hydroxyvitamin D levels ≤25 ng/mL) and systolic blood pressure of 120 to 159 mm Hg...

CONTEXT: Vitamin D insufficiency/deficiency is commonly observed in black youth. OBJECTIVE: The aim was to determine 25-hydroxyvitamin D [25(OH)D] in response to 2000 IU vitamin D supplementation over time; to evaluate the relation between 25(OH)D concentrations and total body fat mass by dual-energy x-ray absorptiometry; and to determine whether vitamin D supplementation improves arterial stiffness measured by pulse wave velocity (PWV). DESIGN: We conducted a randomized, blinded, controlled clinical trial...

BACKGROUND: The optimal public health strategy for maintaining 25-hydroxyvitamin D [25(OH)D] concentrations in schoolchildren in Mongolia is unknown. OBJECTIVE: The objective was to compare the effectiveness of different supplement and fortified milk regimens to increase 25(OH)D concentrations in Mongolian schoolchildren. DESIGN: Twenty-one classrooms of 579 children aged 9-11 y were randomized to interventions with an equivalent content of vitamin D(3): 1) a one-time seasonal supplement of 13,700 IU, 2) 300 IU/d from supplements, 3) 300 IU/d from fortified ultra-high-temperature pasteurized milk from the United States, 4) 300 IU/d from fortified pasteurized Mongolian milk, or 5) unfortified pasteurized Mongolian milk (control)...

The epidemic scourge of rickets in the 19th century was caused by vitamin D deficiency due to inadequate sun exposure and resulted in growth retardation, muscle weakness, skeletal deformities, hypocalcemia, tetany, and seizures. The encouragement of sensible sun exposure and the fortification of milk with vitamin D resulted in almost complete eradication of the disease. Vitamin D (where D represents D2 or D3) is biologically inert and metabolized in the liver to 25-hydroxyvitamin D [25(OH)D], the major circulating form of vitamin D that is used to determine vitamin D status...

No abstract text is available yet for this article.

BACKGROUND: Solar ultraviolet (UV) radiation during the summer and vitamin D supplementation are two major sources of vitamin D for humans at northern latitudes. However, little is known about the relative efficiency of these two vitamin D sources. OBJECTIVES: The main goal was to compare the efficiency of high-dose oral vitamin D3 supplementation (2000 IU per day for 30 days) with a simulated summer UV exposure [10 sunbed sessions to a total dose of 23·8 standard erythema doses (SED)] to improve vitamin D status...

PURPOSE OF REVIEW: Vitamin D has received global attention because of its many health benefits. Although there is general agreement about the importance of vitamin D for bone health, there remains skepticism about the nonskeletal health benefits of vitamin D. This review will not only focus on the vitamin D deficiency pandemic and ways to treat and prevent vitamin D deficiency but will also explore the epigenetic mechanisms of vitamin D that could help explain many of the nonskeletal benefits of enhancing vitamin D status...

No abstract text is available yet for this article.

BACKGROUND: Low 25-hydroxyvitamin D status has been associated with increased cardiovascular events in epidemiologic studies. OBJECTIVE: We assessed whether vitamin D supplementation reduces cardiac failure, myocardial infarction (MI), and stroke through an analysis of the Randomised Evaluation of Calcium Or vitamin D (RECORD) randomized controlled trial (RCT), a systematic review, and a meta-analysis. DESIGN: Two analyses were undertaken...

OBJECTIVE: Observational studies suggest that vitamin D may lower the risk of type 2 diabetes. However, data from long-term trials are lacking. The Vitamin D and Type 2 Diabetes (D2d) study is a randomized clinical trial designed to examine whether a causal relationship exists between vitamin D supplementation and the development of diabetes in people at high risk for type 2 diabetes. RESEARCH DESIGN AND METHODS: D2d was designed with support from a U34 planning grant from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)...

BACKGROUND: Hypovitaminosis D and a low calcium intake contribute to increased parathyroid function in elderly persons. Calcium and vitamin D supplements reduce this secondary hyperparathyroidism, but whether such supplements reduce the risk of hip fractures among elderly people is not known. METHODS: We studied the effects of supplementation with vitamin D3 (cholecalciferol) and calcium on the frequency of hip fractures and other nonvertebral fractures, identified radiologically, in 3270 healthy ambulatory women (mean [+/- SD] age, 84 +/- 6 years)...

BACKGROUND: The supplementation with vitamin D and calcium has been recommended for elderly, specifically those with increased risk of fractures older than 65 years. This study aims to assess the cost-effectiveness of vitamin D and calcium supplementation in elderly women and men with osteoporosis and therefore to assess if this recommendation is justified in terms of cost-effectiveness. METHODS: A validated model for economic evaluations in osteoporosis was used to estimate the cost per quality-adjusted life-year (QALY) gained of vitamin D/calcium supplementation compared with no treatment...

INTRODUCTION: Endothelial dysfunction has been demonstrated to play an important role in pathogenesis of erectile dysfunction (ED) and vitamin D deficiency is deemed to promote endothelial dysfunctions. AIM: To evaluate the status of serum vitamin D in a group of patients with ED. METHODS: Diagnosis and severity of ED was based on the IIEF-5 and its aetiology was classified as arteriogenic (A-ED), borderline (BL-ED), and non-arteriogenic (NA-ED) with penile-echo-color-Doppler in basal condition and after intracaversous injection of prostaglandin E1...

CONTEXT: Overlapping meta-analyses on the same topic are common and often report discordant results. An Endocrine Society (ES) meta-analysis reported that vitamin D with calcium reduced the risk of falls, whereas vitamin D monotherapy had no effect. Despite meta-analyzing an overlapping set of trials, we concluded that vitamin D with or without calcium had no effect on falls. OBJECTIVE: The objective of the study was to determine the reasons for the different conclusions from the two meta-analyses...

The vitamin D hypothesis postulates that lower vitamin D levels are causally associated with increased asthma risk and asthma severity. Multiple epidemiological studies have shown an inverse relationship between circulating vitamin D levels (in the form of 25-hydroxy vitamin D) and asthma severity and control and lung function. However, in the recently published vitamin D and asthma (VIDA) study, vitamin D supplementation failed to show an improvement in asthma control in adults. This article reviews the current epidemiological and trial evidence for vitamin D and asthma and explores some of the possible alternative explanations for previous findings (including "reverse causation" and the importance of studying children and adults)...