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Vitamin D deficiency: studies fuel debate over screening.

The controversy continues: Should the general population be screened for vitamin D deficiency? Should only patients known to be at risk be tested, and if so, which risk factors should be definitive? Experts have weighed in on all sides of the issue, and prestigious professional organizations have taken opposing positions. Meanwhile, as this month's Product Focus indicates, prominent manufacturers are introducing assays to measure levels of the sunshine vitamin to the clinical laboratory market. Several interesting news releases have crossed my desk during the past few months. Here are a few, edited for space.

Vitamin D deficiency common in patients with lung disease

A new study from Korea has uncovered a high prevalence of vitamin D deficiency in individuals with chronic obstructive pulmonary disease (COPD), as well as a significant relationship between vitamin D deficiency and airflow limitations. Exercise capacity also tended to be decreased in participants with vitamin D deficiency.

Vitamin D may keep low-grade prostate cancer from becoming aggressive

Taking vitamin D supplements could slow or even reverse the progression of less aggressive, or low-grade, prostate tumors, without the need for surgery or radiation. In cases of low-grade prostate cancer, many urologists do not treat the disease, but instead do what's called "active surveillance," says Bruce Hollis, PhD. "The cure--surgery or radiation--is probably worse than the disease, so they wait a year and then do another biopsy to see where the patient stands."

However, knowing that they have even low-grade prostate cancer can cause patients excessive anxiety, which prompts some men to undergo an elective prostatectomy, despite the risk of complications. But a man must wait 60 days from the time of his biopsy before he can undergo a prostatectomy, so that inflammation from the biopsy can subside.

Hollis wondered if giving these men vitamin D supplements during the 60-day waiting period would affect their prostate cancer. His previous research had shown that when men with low-grade prostate cancer took vitamin D supplements for a year, 55 percent of them showed decreased Gleason scores or even complete disappearance of their tumors compared to their biopsies a year before.

Vitamin D prevents diabetes and clogged arteries

In recent years, a deficiency of vitamin D has been linked to type 2 diabetes and heart disease. Both disorders are rooted in chronic inflammation, which leads to insulin resistance and the buildup of artery-clogging plaque.

Now, new research in mice at Washington University School of Medicine in St. Louis suggests vitamin D plays a major role in preventing the inflammation that leads to type 2 diabetes and atherosclerosis. Further, the way key immune cells behave without adequate vitamin D may provide scientists with new therapeutic targets for patients with those disorders.

Studying mice that lacked the ability to process vitamin D in immune cells involved in inflammation, the researchers found that the animals made excess glucose, became resistant to insulin action and accumulated plaques in their blood vessels.

"The finding that vitamin D helps regulate glucose metabolism may explain previous epidemiological studies identifying an increased risk of diabetes in patients with vitamin D deficiency," said senior investigator Carlos Bernal-Mizrachi, MD, associate professor of medicine and of cell biology and physiology. "In our study, inactivation of the vitamin D receptor induced diabetes and atherosclerosis, so normalizing vitamin D levels may have the opposite effects."

Vitamin D may help prevent and treat diseases associated with aging

Vitamin D may play a vital role in the prevention and treatment of diseases associated with aging, according to researchers at Loyola University Chicago Marcella Niehoff School of Nursing (MNSON). Researchers reviewed evidence that suggests an association between vitamin D deficiency and chronic diseases associated with aging such as cognitive decline, depression, osteoporosis, cardiovascular disease, high blood pressure, Type 2 diabetes and cancer.

"Vitamin D deficiency is a common, serious medical condition that significantly affects the health and well-being of older adults," said study co-author Sue Penckofer, PhD.

"Better understanding the relationship between vitamin D and chronic diseases in older adults and whether treatment of vitamin D deficiency can prevent or treat these disorders is important given the increasing number of people at risk for these health issues," said co-author Meghan Meehan, MN, FNP.

The Institute of Medicine generally recommends that adults up to 70 years of age take 600 IU of vitamin D daily and adults over the age of 70 consume 800 IU of the nutrient daily.

Vitamin D deficiency, depression linked in international study

Vitamin D deficiency is not just harmful to physical health; it also might impact mental health, according to a team of researchers that has found a link between seasonal affective disorder, or SAD, and a lack of sunlight.

"Rather than being one of many factors, vitamin D could have a regulative role in the development of SAD," said Alan Stewart of the University of Georgia College of Education.

Vitamin D is also involved in the synthesis of serotonin and dopamine within the brain, both chemicals linked to depression, according to the researchers.

"Evidence exists that low levels of dopamine and serotonin are linked to depression, therefore it is logical that there may be a relationship between low levels of vitamin D and depressive symptoms," said the researchers.

Vitamin D deficiency increases poor brain function after cardiac arrest

Vitamin D deficiency increases the risk of poor brain function after sudden cardiac arrest by seven-fold, according to research conducted by Dr. Jin Wi of Yonsei University in Seoul, Korea. Vitamin D deficiency also led to a higher chance of dying after sudden cardiac arrest.

Wi said: "In patients resuscitated after sudden cardiac arrest, recovery of neurological function is very important. Vitamin D deficiency has been reported to be related to the risk of having various cardiovascular diseases, including sudden cardiac arrest. We investigated the association of vitamin D deficiency with neurologic outcome after sudden cardiac arrest, a topic on which there is no information so far."

The researchers prospectively analyzed clinical data from all unconscious patients resuscitated from sudden cardiac arrest of presumed cardiac cause at Severance Cardiovascular Hospital in Seoul. Neurologic outcome was assessed by the Cerebral Performance Category (CPC) score at 6 months after discharge. Good neurologic outcome was defined as a CPC score of 1 or 2, whereas poor neurological outcome was defined as a CPC score of 3 to 5. Vitamin D deficiency was defined as 25-hydroxyvitamin D less than 10 ng/mL.

Patients with a poor neurological outcome had a significantly lower vitamin D level (7.9 ng/mL) compared to those with a good neurological outcome (12.4 ng/mL). The researchers found that 65% of patients with vitamin D deficiency had a poor neurological outcome at 6 months after discharge compared to 23% of patients with healthy vitamin D levels. They also found that 29% of patients with vitamin D deficiency had died at 6 months compared to none of the patients with good vitamin D levels (p= 0.007).

MLO has compiled a number of product items for testing Vitamin D below.


Beckman Coulter's new ACCESS 25(OH) VITAMIN D TOTAL ASSAY provides laboratories with the tools needed to confidently diagnose vitamin D deficiency or insufficiency. Laboratories will benefit with (1) confidence in patient results through standardization to the gold standard 25(OH) Vitamin D Reference Measurement Procedure (RMP) from Ghent University; (2) accurate clinical assessment of vitamin D status provided by measurement of total 25(OH) vitamin D with equimolar measurement of 25(OH) vitamin D2 and 25(OH) vitamin D3; (3) excellent stability and reproducibility with greater storage convenience from an opaque reagent pack designed to prevent light-induced reagent degradation and (4) optimal productivity for both low and high-volume laboratories using the UniCel Dxl and Access 2 Immunoassay Systems.


Bio-Rad's New Specialty Immunoassay Controls

Bio-Rad's Liquichek and Lyphochek Specialty Immunoassay Controls are formulated control materials that can provide values for 25-OH Vitamin D2, D3, and Total Vitamin D. Both controls can be used on major automated instruments, as well as LC/MS methods. Long shelf life and open-vial stability allows users to monitor assay performance across multiple reagent lots as well as effective utilization of the control material. liquichek-specialty-immunoassay-control

DiaSorin s LIAISON 25 OH Vitamin D TOTAL assay and their new LIAISON XL 1,25 Dihydroxyvitamin D Assay

The DiaSorin LIAISON 25 OH Vitamin D TOTAL Assay is a fully automated assay measuring both D2 and D3 for a total result. DiaSorin Vitamin D assays have been used for major national studies such as the Nurse Health Study (NHANES), and have been utilized in clinical studies worldwide. The LIAISON 25 OH Vitamin D TOTAL Assay is certified with the Vitamin D Standardization Program (VDSP). The DiaSorin Assay met the VDSP requirements and no adjustments to the assay or its calibrations were needed. The VDSP is a collaborative initiative organized by the Office of Dietary Supplements of the NIH to help standardize 25 OH Vitamin D measurements across methods. To ensure accurate measurement, all Vitamin D assays should be standardized.

The new LIAISON XL 1,25 Dihydroxyvitamin D assay is an extraction-free, fully automated 1,25 dihydroxyvitamin D assay. The LIAISON XL 1,25 Dihydroxyvitamin D assay eliminates the extraction step, providing higher throughput and a faster time-to-first result of only 65 minutes. The assay is a chemiluminescent immunoassay for the quantitative determination of 1,25 dihydroxyvitamin D in serum and offers excellent precision, accuracy and sensitivity. It will allow laboratories with LIAISON XL Analyzers to run the LIAISON 25 OH Vitamin D TOTAL Assay, LIAISONN-TACT PTH Gen II and LIAISON XL 1,25 Dihydroxyvitamin D together on one instrument utilizing a single serum sample tube.


Randox's Advanced Vitamin D Testing with Quality Control

With over one billion people worldwide suffering from Vitamin D deficiency, the need for reliable test results and accurate diagnosis has never been more apparent. Randox Quality Control has a wide range of QC solutions to meet the needs of every laboratory. The Immunoassay Premium Plus Control offers extensive consolidation, combining over 54 analytes including vitamin D, tumor markers, therapeutic drugs and hormones. Available in three concentrations covering the full clinical range, it offers stability that ensures accurate test results and ultimately, cost savings. All Randox immunology based tests meet the requirements set out in ISO 15189. Reacting in the same manner as a patent sample, this 100% human control is highly commutable.

Visit: immunoassay-controls/immunoassay-controls

Siemans ADVIA Centaur Vitamin D Total Assay

The ADVIA Centaur Vitamin D Total Assay from Siemens Healthcare Diagnostics is a fully equimolar, automated total 25(OH) vitamin D (~100% D2 and D3) assay employing a proprietary monoclonal with minimal 1.1% 3-epi-25(OH) vitamin D3 cross-reactivity aligned to the ID-LC/MS/MS 25(OH) vitamin D Reference Measurement Procedure (RMP), the reference procedure for the Vitamin D Standardization Program (VDSP). This assay can be combined with routine, stat, and specialty assays without compromising time. Results are provided in as little as 18 minutes with a throughput of 240 tests per hour. Laboratories can meet increased testing demands by consolidating vitamin D testing on a fully automated, high-throughput immunoassay system.

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Author:Lenhoff, Alan
Publication:Medical Laboratory Observer
Article Type:Report
Geographic Code:1USA
Date:Jun 1, 2015
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