Newer vitamin D tests often inaccurate, study shows-Faster, less expensive tests may overestimate vitamin D deficiency
June 25, 2012 —
Two new lab tests to measure blood levels of vitamin D are inaccurate more than 40% of the time, according to a new study.-Researchers say newer tests tend to overestimate the number of people who are deficient in vitamin D, a problem that could cause patients to be anxious about their health and may lead to over-treatment.[U1]-The study, which was presented at ENDO 2012, the annual meeting of the endocrine society in Houston, is adding to concerns felt in many laboratories and hospitals around the country that the results of vitamin D tests, which have become some of the most frequently ordered blood tests in medicine, are widely unreliable.-What’s more, experts say, vitamin D testing is often ordered under circumstances where there’s little solid scientific evidence to support its use.–“It’s a huge problem,” says researcher Earle W. Holmes, PhD, a pathologist at Loyola University Stritch School of Medicine, in Chicago.–Experts who were not involved in the research agree.–“The biggest problem is that they’re not even consistent,” says Ravinder J. Singh, PhD, director of the Mayo Clinic’s Endocrinology Laboratory in Rochester, Minn. “At least if they were consistent, you could say, values are half or double, compared to other tests. You can never have confidence” in the results, he tells WebMD.–The new tests, made by Abbott and Siemens, were approved by the FDA last fall.—They’re part of a wave of faster, less expensive tests designed to help laboratories keep up with a boom in demand for vitamin D testing.–Abbott took issue with the study results, pointing to a company-funded study that showed their vitamin D test delivered results that are accurate and comparable to a widely used reference method.—Siemens also defended their test, saying they are reviewing the validity of the study.
Questions Persist About Vitamin D Testing
It’s not the first time questions have been raised about the accuracy of vitamin D tests, however.–In 2009, Quest Diagnostics, one of the largest medical laboratories in the –At the time, industry analysts called it the largest patient recall of a laboratory test in recent memory. The company offered free retesting.–Vitamin D, the “sunshine vitamin,” plays a well-known and important role in bone health. But in recent years, a raft of research has suggested that low vitamin D may be a factor in a host of other health conditions, including depression, diabetes, cancer, heart disease, and autoimmune diseases.–As a result, doctors have increasingly ordered the test to check vitamin D levels in their patients. The number of vitamin D tests has increased six- to 10-fold over the last decade at some hospitals and laboratories. Industry analysts say the vitamin D tests are now one of the most frequently ordered lab tests in medicine.–“The rate of testing has gone up over the last five to 10 years in an almost exponential fashion,” says Naveed Sattar, MD, PhD, a professor of metabolic medicine at the University of Glasgow, in Scotland. Sattar wrote a recent editorial on vitamin D testing for The Lancet, but he was not involved in the research. Sattar says vitamin D testing has raced ahead of the science, leaving doctors in the dark about how to handle abnormal results. —“Many results are coming back in patients who appear otherwise healthy, but they appear to have low levels. And the physicians don’t know what to do, whether they should supplement or not,” Sattar says.—Sattar says there’s little evidence to suggest that supplementing vitamin D is useful, except perhaps as a treatment for bone loss. The recommended dietary allowances for vitamin D in adults up to 70 years old is 600 International Units (IU) and 800 IU for adults over 70.—While the NIH states a tolerable upper intake level of 4,000 IU, Sattar says that back in the 1950s, when vitamin D was first added to foods, the fortification process wasn’t closely monitored and some infants developed dangerously high blood levels of calcium as a result.–Beyond physical harm, however, Sattar says telling someone they are deficient in vitamin D could cause needless anxiety.—“If it were me, I’d be scratching my head. Am I doing something wrong? Should I go spend more time in the sun? Should I be eating certain foods? So that’s a hazard by itself,” he says.–Someone who looks deficient in D might be prescribed supplements and further testing, increasing costs.”I think this does need to be looked at carefully,” Sattar says.
Study Details—Holmes and his team wanted to see how well the new tests performed compared to an older, more expensive, and more time-consuming reference method. They were hoping the hospital could switch to one of the newer tests to save money and time.–They ran blood samples from 163 patients on all three tests. The Abbott Architect test was outside an acceptable margin of error — meaning that the results were either 25% too high or too low, about 40% of the time. The Siemens Centaur2 test was either too high or too low in 48% of samples. In many cases, the newer tests showed that patients were deficient in vitamin D when the reference test indicated they were not.—The new tests use blood proteins called antibodies that bind to vitamin D. They’re faster because they look for vitamin D in samples of whole blood.–In the older, reference method, vitamin D is separated from the blood and measured. The older test can also measure two different forms of vitamin D: Vitamin D2, which is the form of the vitamin found in fortified foods and in the kind of high-potency supplements that doctors prescribe to treat patients; and Vitamin D3, the form of the vitamin that the body makes naturally after skin is exposed to sunlight. The newer test can’t distinguish between the two different types of D.—Holmes says vitamin D2 seems to confuse the tests.–He says the tests’ inability to accurately measure that form of the vitamin means that doctors can’t tell if their patients are getting any benefit from it or if they’re taking their supplements as directed.–“You can’t tell if you’re making a difference for the patients,” Holmes says.–In absolute numbers, the reference test showed 33 patients out of 163 were deficient in vitamin D, while the Abbott test showed 45 people were vitamin D deficient, and the Siemens test pointed to deficiency in 71 patients.–Current guidelines by the Institute of Medicine state a vitamin D level of at least 20 nanograms per milliliter (ng/ml) in the blood as adequate for bone health and overall health. However, other experts, including Holmes, feel that a normal level is 30 ng/ml or higher.—Manufacturers Respond–In a statement issued in response to the study, Abbott, the company that makes the Architect test, says the results of the current study depend on the use of a reference test that is “a very hands-on, labor intensive, manual procedure for which there currently is no standard protocol or calibration method. As a result, this leads to variability of results from lab to lab.”–“In current studies … as well as in recent proficiency surveys, the ARCHITECT Vitamin D test showed excellent precision and reproducibility of results from lab to lab,” the statement reads.—Siemens is checking the study’s accuracy: “Siemens Healthcare Diagnostics is committed to delivering high-quality solutions and services to our customers that enable health care professionals to accurately diagnose, treat, and monitor patients. We are closely reviewing the validity of the claims made in this report along with the design of the methods and analysis used to develop them.”—The wholesale price of the newer tests is estimated to cost around $20 to $25, although patients and insurance companies may be charged more. That’s about half the cost of the older reference test, experts said, which wholesaled for about $50 a test.–This study was presented at a medical conference. The findings should be considered preliminary, as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.–SOURCES: Annual meeting of The Endocrine Society, Houston, June 23-26, 2012.Sattar, N. The Lancet, January 2012.National Institutes of Health, Office of Dietary Supplements: “Dietary Supplement Fact Sheet: Vitamin D.”Earle W. Holmes, PhD, professor of pathology and molecular pharmacology, Stritch School of Medicine, Loyola University, Chicago.Ravinder J. Singh, PhD, director, Endocrinology Laboratory, Mayo Clinic, Rochester, Minn.Naveed Sattar, MD, PhD, professor of metabolic medicine, University of Glasgow, Glasgow, Scotland, U.K.
Low Testosterone Appears To Increase Long-Term Risk Of Death
ScienceDaily (June 17, 2008) — Men may not live as long if they have low testosterone, regardless of their age, according to a new study.–The new study, from Germany, adds to the scientific evidence linking deficiency of this sex hormone with increased death from all causes over time–so-called “all-cause mortality.”—The results should serve as a warning for men with low testosterone to have a healthier lifestyle, including weight control, regular exercise and a healthy diet, said lead author Robin Haring, a PhD student from Ernst-Moritz-Arndt University of Greifswald, Institute for Community Medicine.—“It is very possible that lifestyle determines levels of testosterone,” he said. —In the study, Haring and co-workers looked at death from any cause in nearly 2,000 men aged 20 to 79 years who were living in northeast Germany and who participated in the Study of Health in Pomerania (SHIP). Follow-up averaged 7 years. At the beginning of the study, 5 percent of these men had low blood testosterone levels, defined as the lower end of the normal range for young adult men. The men with low testosterone were older, more obese, and had a greater prevalence of diabetes and high blood pressure, compared with men who had higher testosterone levels, Haring said.—Men with low testosterone levels had more than 2.5 times greater risk of dying during the next 10 years compared to men with higher testosterone, the study found. This difference was not explained by age, smoking, alcohol intake, level of physical activity, or increased waist circumference (a risk factor for diabetes and heart disease), Haring said.—-In cause-specific death analyses, low testosterone predicted increased risk of death due to cardiovascular disease and cancer but not death of any other single cause.—-DPC Biermann, Bad Nauheim, Germany, provided the testosterone reagent, and Novo Nordisc provided partial funding for this analysis.—Detailed results will be presented at The Endocrine Society’s 90th Annual Meeting in San Francisco.—Story Source–The above story is reprinted from materials provided by The Endocrine Society, via EurekAlert!, a service of AAAS.
Sleep Loss Dramatically Lowers Testosterone in Healthy Young Men
ScienceDaily (May 31, 2011) — Cutting back on sleep drastically reduces a healthy young man’s testosterone levels, according to a study published in the June 1 issue of the Journal of the American Medical Association (JAMA).-Eve Van Cauter, PhD, professor in medicine and director of the study, found that men who slept less than five hours a night for one week in a laboratory had significantly lower levels of testosterone than when they had a full night’s sleep. Low testosterone has a host of negative consequences for young men, and not just in sexual behavior and reproduction. It is critical in building strength and muscle mass, and bone density.-“Low testosterone levels are associated with reduced well being and vigor, which may also occur as a consequence of sleep loss” said Van Cauter.—-At least 15% of the adult working population in the US gets less than 5 hours of sleep a night, and suffers many adverse health effects because of it. This study found that skipping sleep reduces a young man’s testosterone levels by the same amount as aging 10 to 15 years. “As research progresses, low sleep duration and poor sleep quality are increasingly recognized as endocrine disruptors,” Van Cauter said. The ten young men in the study were recruited from around the University of Chicago campus. They passed a rigorous battery of tests to screen for endocrine or psychiatric disorders and sleep problems. They were an average of 24 years old, lean and in good health. For the study, they spent three nights in the laboratory sleeping for up to ten hours, and then eight nights sleeping less than five hours. Their blood was sampled every 15 to 30 minutes for 24 hours during the last day of the ten-hour sleep phase and the last day of the five-hour sleep phase. The effects of sleep loss on testosterone levels were apparent after just one week of short sleep. Five hours of sleep decreased their testosterone levels by 10% to 15%. The young men had the lowest testosterone levels in the afternoons on their sleep restricted days, between 2 pm and 10 pm. The young men also self-reported their mood and vigor levels throughout the study. They reported a decline in their sense of well-being as their blood testosterone levels declined. Their mood and vigor fell more every day as the sleep restriction part of the study progressed. Testosterone levels in men decline by 1% to 2% a year as they age. Testosterone deficiency is associated with low energy, reduced libido, poor concentration, and fatigue. The National Heart, Lung, and Blood Institute funded this study. Additional funding came from the National Institute of Diabetes and Digestive and Kidney Diseases, and the National Institutes of Health. Rachel Leproult, PhD, organized and supervised the experiment which took place in the University of Chicago Clinical Research Center.—Story Source-The above story is reprinted from materials provided by University of Chicago Medical Center, via EurekAlert!, a service of AAAS. –Journal Reference–R. Leproult, E. Van Cauter. Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA: The Journal of the American Medical Association, 2011; 305 (21): 2173 DOI: 10.1001/jama.2011.710
Declining Testosterone Levels in Men Not Part of Normal Aging
ScienceDaily (June 23, 2012) — A new study finds that a drop in testosterone levels over time is more likely to result from a man’s behavioral and health changes than by aging. The study results will be presented June 25 at The Endocrine Society’s 94th Annual Meeting in Houston.—“Declining testosterone levels are not an inevitable part of the aging process, as many people think,” said study co-author Gary Wittert, MD, professor of medicine at the University of Adelaide in Adelaide, Australia. “Testosterone changes are largely explained by smoking behavior and changes in health status, particularly obesity and depression.”–Many older men have low levels of the sex hormone testosterone, but the cause is not known. Few population-based studies have tracked changes in testosterone levels among the same men over time, as their study did, Wittert said.
In this study, supported by the National Health and Medical Research Council of Australia, the authors analyzed testosterone measurements in more than 1,500 men who had measurements taken at two clinic visits five years apart. All blood testosterone samples underwent testing at the same time for each time point, according to Wittert.—After the researchers excluded from the analysis any men who had abnormal lab values or who were taking medications or had medical conditions known to affect hormones, they included 1,382 men in the data analysis. Men ranged in age from 35 to 80 years, with an average age of 54.—On average, testosterone levels did not decline significantly over five years; rather, they decreased less than 1 percent each year, the authors reported. However, when the investigators analyzed the data by subgroups, they found that certain factors were linked to lower testosterone levels at five years than at the beginning of the study.—“Men who had declines in testosterone were more likely to be those who became obese, had stopped smoking or were depressed at either clinic visit,” Wittert said. “While stopping smoking may be a cause of a slight decrease in testosterone, the benefit of quitting smoking is huge.”—Past research has linked depression and low testosterone. This hormone is important for many bodily functions, including maintaining a healthy body composition, fertility and sex drive. “It is critical that doctors understand that declining testosterone levels are not a natural part of aging and that they are most likely due to health-related behaviors or health status itself,” he said.—Unmarried men in the study had greater testosterone reductions than did married men. Wittert attributed this finding to past research showing that married men tend to be healthier and happier than unmarried men. “Also, regular sexual activity tends to increase testosterone,” he explained.—The study findings were presented by Andre Araujo, PhD, who was a visiting professor at the University of Adelaide and is vice president of epidemiology at New England Research Institutes, Watertown, Mass.–Story Source-The above story is reprinted from materials provided by Endocrine Society, via Newswise.
World’s First GM Babies Born
The world’s first geneticallymodified humans have been created, it was revealed last night.—The disclosure that 30 healthy babies were born after a series of experiments in the United States provoked another furious debate about ethics.—So far, two of the babies have been tested and have been found to contain genes from three ‘parents’.—Fifteen of the children were born in the past three years as a result of one experimental programme at the Institute for Reproductive Medicine and Science of St Barnabas in New Jersey.–The babies were born to women who had problems conceiving. Extra genes from a female donor were inserted into their eggs before they were fertilised in an attempt to enable them to conceive.–Genetic fingerprint tests on two one-year- old children confirm that they have inherited DNA from three adults –two women and one man.—The fact that the children have inherited the extra genes and incorporated them into their ‘germline’ means that they will, in turn, be able to pass them on to their own offspring.–Altering the human germline – in effect tinkering with the very make-up of our species – is a technique shunned by the vast majority of the world’s scientists.—Geneticists fear that one day this method could be used to create new races of humans with extra, desired characteristics such as strength or high intelligence.[U2] Writing in the journal Human Reproduction, the researchers, led by fertility pioneer Professor Jacques Cohen, say that this ‘is the first case of human germline genetic modification resulting in normal healthy children’.–Some experts severely criticised the experiments. Lord Winston, of the Hammersmith Hospital in West London, told the BBC yesterday: ‘Regarding the treat-ment of the infertile, there is no evidence that this technique is worth doing . . . I am very surprised that it was even carried out at this stage. It would certainly not be allowed in Britain.’—John Smeaton, national director of the Society for the Protection of Unborn Children, said: ‘One has tremendous sympathy for couples who suffer infertility problems. But this seems to be a further illustration of the fact that the whole process of in vitro fertilisation as a means of conceiving babies leads to babies being regarded as objects on a production line.–‘It is a further and very worrying step down the wrong road for humanity.’ Professor Cohen and his colleagues diagnosed that the women were infertile because they had defects in tiny structures in their egg cells, called mitochondria.–They took eggs from donors and, using a fine needle, sucked some of the internal material – containing ‘healthy’ mitochondria – and injected it into eggs from the women wanting to conceive.-Because mitochondria contain genes, the babies resulting from the treatment have inherited DNA from both women. These genes can now be passed down the germline along the maternal line.–A spokesman for the Human Fertilisation and Embryology Authority (HFEA), which regulates ‘assisted reproduction’ technology in Britain, said that it would not license the technique here because it involved altering the germline.
Jacques Cohen is regarded as a brilliant but controversial scientist who has pushed the boundaries of assisted reproduction technologies. He developed a technique which allows infertile men to have their own children, by injecting sperm DNA straight into the egg in the lab. Prior to this, only infertile women were able to conceive using IVF. Last year, Professor Cohen said that his expertise would allow him to clone children –a prospect treated with horror by the mainstream scientific community. ‘It would be an afternoon’s work for one of my students,’ he said, adding that he had been approached by ‘at least three’ individuals wishing to create a cloned child, but had turned down their request