Vitamin D supplementation to prevent acute respiratory infections: a systematic review and meta-analysis of aggregate data from randomised controlled trials.

Background: A 2017 meta-analysis of data from 25 randomised controlled trials (RCTs) of vitamin D supplementation for the prevention of acute respiratory infections (ARIs) revealed a protective effect of this intervention. We aimed to examine the link between vitamin D supplementation and prevention of ARIs in an updated meta-analysis.

Methods: For this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and the ClinicalTrials.

Vitamin D and Abdominal Aortic Calcification in Older African American Women, the PODA Clinical Trial.

Abdominal aortic calcification (AAC) detected on lateral vertebral fracture assessment is associated with increased cardiovascular risk. Vitamin D deficiency and toxicity have been linked with vascular calcification. The objective of this study was to determine the effect of high-dose vitamin D on the progression of AAC.

Correction: Differential effects of growth hormone and alfa calcidol on trabecular and cortical bones in hypophysectomized rats.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Vitamin D and Acute Respiratory Infections-The PODA Trial.

Background: There is considerable heterogeneity in clinical trials examining the role of vitamin D in the prevention of acute respiratory infections (ARIs).

Methods: The primary aim of the Physical Performance, Osteoporosis, and Vitamin D in Older African-American Women (PODA) trial was the prevention of bone loss and decline in physical performance. A questionnaire about ARIs was administered every 3 months for 3 years to 260 black American women in a double-blind randomized clinical trial that had a placebo group and a vitamin D supplementation group.

Correction to: Effects of growth hormone on bone modeling and remodeling in hypophysectomised young female rats: a bone histomorphometric study.

The following corrections are found in the original publication of the article and corrected as below.

Vitamin D and Falls in Older African American Women: The PODA Randomized Clinical Trial.

Background: Limited information is available on the influence of vitamin D on falls in older high-functioning black American women. Endocrine Society guidelines propose serum 25(OH)D levels over 30 ng/mL.

Objective: To determine if maintenance of serum 25(OH)D above 30 ng/mL protects against falls.

Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis.

Background: Randomised controlled trials (RCTs) exploring the potential of vitamin D to prevent acute respiratory infections have yielded mixed results. Individual participant data (IPD) meta-analysis has the potential to identify factors that may explain this heterogeneity.

Objectives: To assess the overall effect of vitamin D supplementation on the risk of acute respiratory infections (ARIs) and to identify factors modifying this effect.

Physical Performance and Vitamin D in Elderly Black Women-The PODA Randomized Clinical Trial.

Context: There is limited information on the influence of vitamin D on physical performance in black Americans.

Objective: To determine if maintenance of serum 25(OH)D >75 nmol/L prevents a decline in physical performance.

Design: The Physical Performance, Osteoporosis and Vitamin D in African American Women (PODA) trial had a prospective, randomized, placebo controlled, double-dummy design with two arms: one of which is placebo vitamin D3 adjusted to maintain serum 25(OH)D >75 nmol/L.

Cognition and Vitamin D in Older African-American Women- Physical performance and Osteoporosis prevention with vitamin D in older African Americans Trial and Dementia.

Objectives: To examine the effect of 25-hydroxyvitamin D (25(OH)D) levels recommended by Endocrine Society guidelines (>30 ng/mL) on cognition in healthy older African-American women over 3 years.

Design: Randomized, double-blind, placebo-controlled clinical trial.

Setting: Bone Mineral Research Center at New York University Winthrop Hospital.

Safety of calcium and vitamin D supplements, a randomized controlled trial.

Objective: It is anticipated that an intake of vitamin D found acceptable by Endocrine Society Guidelines (10 000 IU/day) with co-administered calcium supplements may result in frequent hypercalciuria and hypercalcaemia. This combination may be associated with kidney stones. The objective of this study was to compare the episodes of hypercalciuria and hypercalcaemia from calcium supplements co-administered with 10 000 IU or 600 IU vitamin D daily.

The relationship of Physical performance and Osteoporosis prevention with vitamin D in older African Americans (PODA).

Rationale: Vitamin D deficiency is associated with bone loss, poor muscle strength, falls and fracture. This information in older African Americans (AAs) is sparse.

Objective: The study of the relationship of Physical performance, Osteoporosis prevention with vitamin D in older African Americans (PODA) is a randomized, double-blind, placebo-controlled 3-year trial examining the effect of vitamin D on bone loss and physical performance in older AA women.

Effect of Vitamin D on Falls and Physical Performance.

Recent understanding has highlighted the importance of extraskeletal role of vitamin D. Despite numerous observational and interventional studies over the last two decades, the apparent divergent clinical findings have intensified the controversy regarding this role of vitamin D in older adults. This article reviews the existing literature and summarizes the current knowledge of vitamin D status and vitamin D supplementation on falls and physical performance, describes the putative mechanisms underlying this association, and reflects on the controversy surrounding vitamin D recommendations in older adults.

Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data.

 To assess the overall effect of vitamin D supplementation on risk of acute respiratory tract infection, and to identify factors modifying this effect. Systematic review and meta-analysis of individual participant data (IPD) from randomised controlled trials. Medline, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.

Assessing Vitamin D Status in African Americans and the Influence of Vitamin D on Skeletal Health Parameters.

In the United States, there is a significant disparity in vitamin D status among individuals of African versus European descent. Despite having lower total 25-hydroxyvitamin D levels compared with white Americans, African Americans have higher bone mineral density and lower fracture risk. This article reviews classical and nonclassical vitamin D physiology, describes whether total versus free 25-hydroxyvitamin D is a better marker of vitamin D status in African Americans, and summarizes the influence of vitamin D status and vitamin D supplementation on markers of vitamin D bioactivity (intestinal calcium absorption, parathyroid hormone secretion, bone mineral density, fracture) in African Americans.

Urinary calcium excretion in postmenopausal African American women.

Aim: The objective of this study was to develop a reference range for urine calcium excretion (both 24-hour and fasting) for African American women compared to White women. In addition, the variables that determine urine calcium excretion were identified.

Material: Data were analyzed for baseline studies of healthy postmenopausal volunteers who participated in seven separate studies conducted at one site.

Questions About Vitamin D for Primary Care Practice: Input From an NIH Conference.

There is considerable consumer and physician interest in vitamin D as a possible therapeutic agent for a range of clinical conditions and, despite mixed evidence, the interest does not appear to lessen. Some clinicians believe that consumption of vitamin D is inadequate and, in turn, advocate vitamin D supplementation to increase serum levels of the nutrient. However, evidence concerning the role of vitamin D in health and disease is conflicting, and primary care physicians have little time to sort through the data and may find it difficult to advise their patients.

The vitamin d dose response in obesity.

Objective: The prevalence of vitamin D inadequacy is high in obese individuals. Determining the response of serum 25-hydroxyvitamin D (25[OH]D) to vitamin D3 supplementation in obese and nonobese individuals may lead to concurrent recommendations for optimal vitamin D intake in these populations. The objective of this study was to determine the dose response of vitamin D3 in subjects with a body mass index ≥35 kg/m2.

Vitamin D supplementation increases calcium absorption without a threshold effect.

Background: The maximal calcium absorption in response to vitamin D has been proposed as a biomarker for vitamin D sufficiency.

Objective: The objective was to determine whether there is a threshold beyond which increasing doses of vitamin D, or concentrations of serum 25-hydroxyvitamin D [25(OH)D], no longer increase calcium absorption.

Design: This was a placebo-controlled, dose-response, randomized, double-blind study of the effect of vitamin D on calcium absorption in healthy postmenopausal women.