May 23, 2011 -- African-Americans with multiple sclerosis (MS) may be more likely to have low vitamin D levels than African-Americans without the disease.
A new study shows 77% of African-Americans with MS were vitamin D deficient compared with 71% of African-Americans without the disease.
Researchers say much of the difference in vitamin D levels may be explained by variations in climate and geography, but the findings add further evidence to the growing link between vitamin D and multiple sclerosis risk.
"These findings may provide a mechanism to help explain how genes and the environment interact to produce MS," says researcher Ari J. Green, MD, of the University of California, San Francisco, in a news release.
Researchers say MS is not as common in African-Americans as it is in whites, but the muscle-weakening disease tends to be more severe in African-Americans.
Vitamin D is an essential nutrient derived from exposure to sunlight or through supplementation.
Previous studies have shown that African-Americans tend to have lower vitamin D levels than whites, possibly due to the higher levels of melanin in their skin. Melanin is a pigment in the skin that acts as a filter of ultraviolet (UV) light, which limits the amount of vitamin D that the body can produce in response to sunlight exposure.
In this study, published in Neurology, researchers compared vitamin D levels in 339 African-Americans with multiple sclerosis and 342 without the disease.
The results showed 77% of those with MS were vitamin D deficient compared with 71% of those without the disease. Vitamin D levels were not associated with disease severity.
Researchers say people with MS were exposed to a lower monthly UV index (an average of 3.8 vs. 4.8) and lived an average of one degree of latitude farther north than those without the disease. They say the link between low vitamin D levels and MS was weaker but still significant after accounting for these differences.
The study also showed that people with a higher proportion of European ancestry in their genes were less likely to have low vitamin D levels.
Researchers say further studies are needed in multiple ethnic groups to explore the relationship between vitamin D levels and multiple sclerosis.
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May 16, 2011 -- A small study that tested vitamin D against a placebo in patients with chronic lung disease found that those getting the vitamin D could breathe better and exercise more than those on the dummy pills.
The 50 study participants were patients with chronic obstructive pulmonary disease (COPD) who were part of a three-month pulmonary rehabilitation program in Belgium.
Half were randomly assigned to get a high-dose vitamin D supplement; the other half got a dummy pill on the same schedule.
At the end of the study, those getting 100,000 international units (IU) of vitamin D each month had improvement in respiratory muscle strength and could exercise longer and more intensely than those who were not getting vitamin D.
“I think it’s important,” says study researcher Miek Hornikx, physiotherapist and doctoral student in the department of pneumology at the Katholieke Universiteit Leuven in Leuven, Belgium. “But more studies are needed, mainly to look at the mechanisms by which vitamin D can improve muscular function."
The study was presented at the 2011 American Thoracic Society International Conference in Denver.
Studies show that people with COPD often have low levels of vitamin D, a vitamin best known for its role in keeping bones strong.
A 2010 report in the journal Thorax, for example, found that 60% of patients with severe COPD and 77% with very severe COPD had blood levels of vitamin D under 20 ng/mL, a level experts say is insufficient.
Some of the cause may be inherited. Certain gene variants have been shown to increase the risk of having low vitamin D levels.
But many experts think people with COPD may have low levels of vitamin D simply because they get less sun.
The body uses UV rays from sunlight to manufacture vitamin D.?
“Getting outside is hard if you’re sick,” says Kevin K. Brown, MD, vice chairman of the department of medicine at National Jewish Health in Denver.
Vitamin D’s benefits may extend well beyond bone health. It has also been shown to play a role in muscle health. Low levels have been shown, for example, to be associated with an increased risk of falls in men and slower walking speeds and poorer balanced in women.
“Since vitamin D is often depleted in patients with COPD, we wanted to see if vitamin D supplementation would have a beneficial effect on rehabilitation among these patients, perhaps by increasing muscle strength,” Hornikx says.
For the study, researchers enrolled 50 COPD patients whose symptoms, including shortness of breath and coughing and phlegm, had been getting worse.
All the patients participated in a three-month pulmonary rehabilitation program. Half were randomly selected to receive once-monthly, high-dose vitamin D supplements; the other half were given a placebo pill.
May 12, 2011 -- Ultraviolet light therapy and vitamin D creams are widely prescribed treatments for psoriasis, and now a new study may help explain why they work for so many patients.
Researchers say the vitamin D-based treatments increase the binding of a peptide called cathelicidin to DNA, which, in turn, inhibits the inflammatory response that triggers psoriasis.
The finding may one day lead to better treatments for the painful skin condition that specifically target cathelicidin, study researcher Jurgen Schauber, MD, of Ludwig-Maximillian University in Munich, Germany, tells WebMD.
“We were able to identify a novel, pro-inflammatory signaling pathway which helps us understand why [vitamin D-based] treatments work,” he says.
As many as 7.5 million Americans have psoriasis, a chronic, inflammatory disease that commonly causes thick, itchy, scaly patches on the skin.
While the causes are not completely understood, it is believed that the scaly patches occur when the immune system identifies healthy cells as dangerous ones and goes into overdrive, activating protein complexes called inflammasomes.
In the newly published study, Schauber and colleagues analyzed genes in skin biopsies from psoriasis patients and healthy volunteers.
They found that a gene encoding the newly discovered protein AIM2 was highly activated in the skin of the psoriasis patients, but not the samples from people without psoriasis.
Schauber explains that along with other proteins, AIM2 is a key player in activating an inflammation-triggering inflammasome.
Topical vitamin D treatments and ultraviolet B light therapy, which promotes vitamin D production in the skin, help DNA inhibit inflammasome activation by controlling cathelicidin production.
Drugs that specifically target cathelicidin expression could prove useful in the treatment of psoriasis, the researchers conclude.
The study appears in the May 11 issue of Science Translational Medicine.
Henry Lim, MD, chief of dermatology at Detroit’s Henry Ford Hospital, says the study increases the understanding of the role of vitamin D in psoriasis.
“We have used these treatments for a long time, but we haven’t had a full understanding of why they work,” Lim tells WebMD. “This is one potential mechanism.”
He says UBV light therapy is an effective treatment for about 70% of patients and vitamin D creams improve symptoms in about 50% to 60% of patients with mild psoriasis.
But there is little suggestion that taking vitamin D supplements has any impact on psoriasis symptoms. Lim recommends against excess sun exposure or commercial tanning to increase vitamin D levels.
“Obviously sun exposure is associated with skin aging and skin cancer,” he says. “In the clinic exposures are controlled and much safer.”
May 10, 2011 -- Newborns with low vitamin D levels have a sixfold higher risk of lung infections with respiratory syncytial virus (RSV), Dutch researchers say.
RSV is the major cause of serious lung infections in infants. During the first 12 months of life, it's the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia in the U.S.
Low vitamin D levels have been suspected of playing a role in vulnerability to RSV. This led Mirjam E. Belderbos, MD, of the Utrecht University Medical Center in the Netherlands, and colleagues to measure vitamin D levels in the cord blood of 156 newborns and then to follow the children for one year.
At birth, more than a quarter of the infants had low vitamin D -- serum levels of less than 20 ng/mL. During their first year of life, these kids had a sixfold higher risk of RSV lung infection than did the 46% of kids whose vitamin D levels at birth were at least 30 ng/mL.
"We demonstrated that 54% of healthy newborns in the Netherlands are born with insufficient [vitamin D] concentrations required for maximum health, and that low plasma concentrations of [vitamin D] are associated with increased risk of RSV lower-respiratory tract infections in the first year of life," Belderbos and colleagues report.
It's not just the Netherlands. Other Western nations, including the U.S., have similar rates of low vitamin D.
U.S. researchers reported in 2010 that at a single Boston hospital, 58% of infants and 36% of mothers had low vitamin D levels (under 20 ng/mL). Severe vitamin D deficiency (defined as lower than 15 ng/mL) was seen in 38% of the infants and in 23% of the mothers.
Vitamin D is a hormone that the body makes when exposed to direct sunlight. Belderbos and colleagues found that infants born in July had the highest vitamin D levels, while those born in December had the lowest levels.
RSV isn't the only problem for kids with low vitamin D. Vitamin D deficiency -- levels below 12 ng/mL -- causes the soft, weak bones of rickets. Rickets was common in the days before vitamin D was added to milk.
But low vitamin D during pregnancy may play a role in a wide range of diseases in children: type 1 diabetes, multiple sclerosis, schizophrenia, infant wheeze, and respiratory infections.
How can vitamin D affect infections? Belderbos and colleagues suggest three ways:
Just under half of the women in the Dutch study took vitamin D3 supplements. Infants born to these women had significantly higher vitamin D levels at birth. However, the study was too small to show whether maternal vitamin D supplements protected infants from RSV lung infection.
The researchers call for clinical trials to test whether vitamin D supplements during pregnancy can protect children from RSV.
Belderbos and colleagues report their findings in the May 9 online issue of Pediatrics.
April 29, 2011 -- Women with low vitamin D levels may have an increased risk for the most aggressive breast cancers, new research suggests.
Several earlier studies have suggested a link between low vitamin D levels and breast cancer risk. But the new study is among the first to examine vitamin D insufficiency and poor prognosis.
Researchers from the University of Rochester Medical Center examined vitamin D levels in 155 breast cancer patients in the months before or after they had surgery to treat their disease.
They found suboptimal vitamin D levels to be highly predictive of the presence of biological markers associated with more aggressive tumors.
Women in the study with triple-negative tumors, which do not respond to hormone treatments, were almost three times more likely to have suboptimal vitamin D levels as women with other breast cancers.
Triple-negative tumors are difficult to treat and they tend to have a worse prognosis than other breast cancers.
“We consistently saw lower vitamin D levels in breast cancer patients with poor prognostic markers,” study researcher Luke Peppone, PhD, tells WebMD.
The study participants had surgery for breast cancer between January 2009 and September 2010. Based on testing conducted within a year before or after surgery, the patients were considered to have either optimal (32 ng/mL or greater) or suboptimal (less than 32 ng/mL) vitamin D levels.
All patients also had a relatively new test designed to predict their risk of recurrence based on the presence of genes that have been identified with breast cancer.
The researchers reported a strong correlation between decreasing vitamin D levels and increasing scores on the predictive test.
African-American women and premenopausal women were more likely to have suboptimal vitamin D levels than older, white women.
The study is published online in the Annals of Surgical Oncology.
While the research does not prove that low vitamin D levels influence outcomes in women who develop breast cancers, Peppone says more study is certainly warranted.
American Cancer Society Deputy Chief Medical Officer Len Lichtenfeld, MD, agrees.
“The vitamin D research as a whole is certainly intriguing, but we have learned many times before that what appears intriguing doesn’t always hold up when properly studied,” he tells WebMD.
The independent health policy group Institute of Medicine (IOM) recently weighed in on vitamin D and cancer, calling the evidence that vitamin D prevents breast and other cancers “inconsistent and inconclusive.”
Vitamin D is produced by the body from the sun’s rays. It is found in salmon, tuna, and other oily fish and is added to dairy products. But experts agree that it would be very difficult to get enough vitamin D from food sources alone.
The panel recommended a daily intake of 600 international units (IU) from age 1 to 70 and 800 IU over age 70.
“The [IOM] experts did not dismiss the idea that vitamin D may have a role in preventing cancer or affecting its course once it develops,” Lichtenfeld says. “They recognized that the research is trending in this direction, but did not feel that it met the threshold for concluding that a cause-and-effect relationship exists.”
Breast cancer specialist Sharon M. Rosenbaum Smith, MD, of St. Luke’s-Roosevelt Medical Center in New York, agrees that the new study deserves follow-up.
“We are seeing study after study suggesting a link between vitamin D and breast cancer,” she says. “But what that exact link is has yet to be determined.”
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April 11, 2011 -- Women younger than 75 who get sufficient vitamin D in their diets appear to have a reduced risk of a leading cause of blindness, new research indicates.
In the study, researchers say women under 75 who got the most vitamin D had a 59% decreased risk of developing age-related macular degeneration, compared to women with the lowest vitamin D intake.
Researchers also found that the women who had a blood vitamin D level higher than 38 nmol/L had a 48% decreased risk of early age-related macular degeneration (AMD). A blood level of 50 nmol/L is considered sufficient, according to the Institute of Medicine.
The top food sources of vitamin D among women in the study were milk, fish, fortified margarine, and fortified cereal. No correlation was found between self-reported time in direct sunlight, which is also a source of vitamin D, and AMD.
Age-related macular degeneration is a chronic, late-onset disease that results in degeneration of the macula, the central portion of the retina that allows for focused, precise vision. It is the leading cause of adult irreversible vision loss and affects about 8.5 million Americans aged 40 and older, the researchers say.
Study author Amy E. Millen, PhD, of the University of Buffalo, and colleagues studied data from 1,313 women to investigate whether a well-known blood test for vitamin D status might be associated with early age-related macular degeneration.
The blood test, called serum 25 (OH) D, measures vitamin D exposure from oral sources and sunlight, Millen says in a news release.
The researchers say that their study is the second to find an association between age-related macular degeneration and vitamin D levels. More studies are needed to verify their findings, the researchers say, as well as to understand more about the potential interaction between vitamin D levels and genetic and lifestyle factors concerning the risk of early development of macular degeneration.
The study is published in the April issue of the Archives of Ophthalmology.
March 14, 2011 -- A study of newly diagnosed patients with Parkinson’s disease found a high prevalence of vitamin D insufficiency, but vitamin D levels did not continue to decline as the disease progressed.
The research is one of several studies suggesting a link between low vitamin D levels and Parkinson’s disease, a brain disorder that leads to tremors and problems with balance and coordination. Parkinson’s affects as many as 1 million older Americans.
In a study from Finland published last summer, people with the lowest levels of vitamin D were significantly more likely to develop Parkinson’s over almost three decades of follow-up, compared to people with the highest blood levels of the vitamin.
In the newly published study, almost 70% of patients with a recent diagnosis of Parkinson’s disease had low blood levels of the vitamin.
But it is not yet clear if vitamin D insufficiency raises Parkinson’s risk or if having high levels of the vitamin is protective, says study researcher Marian L. Evatt, MD, of Emory University School of Medicine and the Atlanta Veterans Affairs Medical Center.
“More research is needed to figure this out,” she tells WebMD. “There is certainly an association, but we can’t say if it is causal.”
Most people get the majority of their vitamin D from exposure to sunlight. Salmon, tuna, and fortified milk and other dairy products are the main food sources of the vitamin.
There are suggestions from animal and other studies that vitamin D protects the brain and central nervous system.
If this is the case, it would stand to reason that people with low vitamin D levels would have an increased risk for developing Parkinsons’ and other neurodegenerative disorders like Alzheimer’s disease as they age, Evatt says.
In earlier research, Evatt and colleagues found low vitamin D levels in 55% of Parkinson’s patients they studied, compared to 41% of patients with Alzheimer’s disease and 36% of healthy, elderly study participants.
In the newly published study, the researchers examined the prevalence of vitamin D insufficiency in untreated patients with early Parkinson’s disease. They found that 69.4% of patients had vitamin D insufficiency and 26% had vitamin D deficiency.
The patients were followed for an average of 20 months.
“Contrary to our expectations that vitamin D levels might decrease over time because of disease related inactivity and reduced sun exposure, vitamin D levels increased over the study period,” the researchers write.
They conclude that Parkinson’s patients may have low vitamin D levels for many years before disease symptoms become evident.
Neurologist Andrew Feigin, MD, agrees more study is needed to better understand vitamin D’s role, if any, in Parkinson’s disease.
Feigin is an associate investigator with the Feinstein Institute for Medical Research in Manhasset, N.Y.
“The increase in vitamin D levels over the course of the study, during which there was a significant worsening in Parkinson’s disease signs and symptoms, suggests that simply raising vitamin D levels may not result in improved Parkinson’s symptoms,” he says in a news release.
Feb. 25, 2011 -- Children who don’t get enough vitamin D may be at increased risk of developing allergies, new research indicates.
Researchers in New York examined serum vitamin D levels in the blood of more than 3,100 children and adolescents and 3,400 adults.
No association was found between low vitamin D levels and allergies in adults, but the link was significant in children and adolescents.
Children and adolescents aged 1 to 21 with low vitamin D levels were at increased risk of having sensitivities to 11 of 17 allergens tested, including environmental and food allergies.
For example, children who had vitamin D deficiency, which was defined as less than 15 nanograms of vitamin D per milliliter of blood, were 2.4 times more likely to have a peanut allergy than kids with sufficient levels, or 30 nanograms of vitamin D per milliliter of blood.
Children with low vitamin D levels also had increased risk of allergic sensitization to shrimp, dogs, cockroaches, ragweed, oak, ryegrass, Bermuda grass, and thistle.
The data came from the National Health and Nutrition Examination Survey 2005-2006 (NHANES), which is a program of studies aimed at assessing the health and nutritional status of adults and children in the U.S.
The study participants underwent blood tests measuring levels of Immunoglobulin E(IgE), a protein that is produced when the immune system responds to allergens.
Researchers say their findings don’t prove that insufficient vitamin D causes allergies in children and adolescents, but strongly suggests that young people should get adequate amounts of the vitamin.
“The latest dietary recommendations calling for children to take in 600 IU of vitamin D daily should keep them from becoming vitamin D deficient,” researcher Michal Melamed, MD, MHS, of the Albert Einstein College Medicine of Yeshiva University, says in a news release.
The study says vitamin D is thought to have anti-inflammatory effects in the body.
The researchers note that the prevalence of vitamin D deficiency is increasing in the U.S., and so is the prevalence of food allergies.
The study is published in the Feb. 17 online edition of the Journal of Allergy and Clinical Immunology.
