MedicalResearch.com Interview with:
Juan C. Celedón, MD, DrPH, ATSF
Niels K. Jerne Professor of Pediatrics
Professor of Medicine, Epidemiology and Human Genetics
University of Pittsburgh
Division Chief, Pulmonary Medicine
UPMC Children’s Hospital of Pittsburgh
Pittsburgh, PA 15224
MedicalResearch.com: What is the background for this study? Response: Findings from observational studies suggested that vitamin D levels below 30 ng/ml are associated with worse asthma and severe asthma attacks. Based on those results, we conducted a randomized, double-blind, placebo-controlled clinical trial of vitamin D3 supplementation to prevent severe asthma attacks in 192 high-risk children with asthma aged 6 to 16 years who had moderately low vitamin D levels and were taking low-dose inhaled steroids.
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MedicalResearch.com Interview with:
Augusto A. Litonjua, M.D., M.P.H.
Professor - Department of Pediatrics, Pulmonology
Interim Chief - Department of Medicine , Pulmonary Diseases and Critical Care
Professor - Department of Medicine , Pulmonary Diseases and Critical Care
University of Rochester
MedicalResearch.com: What is the background for this study? Response: Vitamin D deficiency and insufficiency is prevalent worldwide. Prior observational studies have shown that low vitamin D levels have been associated with the development of asthma. Animal studies have reported that antenatal vitamin D is important for lung development in utero. Thus, we conducted a randomized, double-blind, controlled trial of vitamin D supplementation in pregnant women to see if we could prevent the development of asthma and wheezing illnesses in young children. The initial report of the trial results showed that children born to mothers in the vitamin D supplementation arm had lower risks for developing either asthma or recurrent wheezing episodes over the first 3 years, but this was not statistically significant (p=0.051)(Litonjua et al. JAMA 2016). (more…)
MedicalResearch.com Interview with:
Robert ClarkeMD, FRCP, FFPH, FFPHI, MSc, DCH
Professor of Epidemiology and Public Health Medicine
Clinical Trial Service Unit (CTSU)
Nuffield Department of Population Health
University of Oxford
MedicalResearch.com: What is the background for this study? Response: Approximately 1 in 2 women and 1 in 5 men aged 50 years or older will suffer from an osteoporotic fracture in their remaining lifetime. Hip fracture is the most serious type of osteoporotic fracture with an approximately 30% risk of death in the year following a hip fracture. Vitamin D is essential for optimal musculoskeletal health by promotion of calcium absorption, and mineralisation of osteoid tissue formation in bone and maintenance of muscle function. Low vitamin D status causes secondary hyperparathyroidism, bone loss and muscle weakness. Observational studies have reported that lower blood concentrations of vitamin D are associated with higher risks of falls and fractures.
Combined supplementation with 800 IU/day vitamin D and 1200 mg/day calcium has been recommended for prevention of fractures in older adults living in institutions and in those with low vitamin D status. However, previous trials and meta-analyses of vitamin D alone, or in combination with calcium for prevention of fracture in either community-dwelling or general population settings reported conflicting results, with some reporting protective effects against fractures, but others demonstrated no beneficial effects. However, most of the previous trials had only limited power to detect differences in risk of fracture predicted by the observational studies, largely because of a combination of small sample size, relatively low equivalent daily doses of vitamin D, intermittent dosing regimens (>1 month), and short duration of follow-up. In addition, interpretation of the results of previous meta-analyses of such trials is complicated by use of variable inclusion criteria, inappropriate statistical methods, inclusion of multiple small trials with very few fracture events, in addition to failure to report achieved differences in blood 25(OH)D concentrations.
We summarised the available evidence to guide clinical practice and future research, by conducting parallel meta-analyses of:
(i) observational studies of risks of fracture associated with prolonged differences in blood concentrations of 25(OH)D;
(ii) randomised trials of vitamin D alone versus placebo or no treatment for prevention of fracture; and
(iii) randomised trials of calcium and vitamin D versus placebo or no treatment for prevention of fracture.In addition, we reviewed the design of the ongoing randomised trials assessing the effects of higher doses of vitamin D alone or in combination with calcium for prevention of fracture.
MedicalResearch.com Interview with:
Eduardo Villamor, M.D., M.P.H., Dr.P.H.
Professor, Epidemiology
School of Public Health
University of MichiganAnn Arbor, Michigan
MedicalResearch.com: What is the background for this study?
Response: Vitamin D deficiency has been related to adverse mental health outcomes, including depression and schizophrenia, in adults. Some studies have suggested a potential role of vitamin D status prenatally on other neurodevelopmental outcomes in childhood. However, few studies had extended into adolescence which is the life period when certain mental health issues that predict disease later in life, namely behavioral problems, first appear.(more…)
MedicalResearch.com Interview with:
Hans Bisgaard, DMSc, MD
Head of COPSAC, Professor
Professor of Pediatrics, University of Copenhagen
Founder and Head of the Copenhagen Prospective Studies on Asthma in Childhood;
Gentofte Hospital, University of Copenhagen and Naestved Hospital
MedicalResearch.com: What is the background for this study? Response: Enamel defects is a global health challenges affecting typically 1/3 of school children and more in some regions. It leads to break down of the teeth and caries later on.
MedicalResearch.com: What are the main findings?Response: Supplementation with high-dose vitamin D compared to standard dose in the third pregnancy trimester in a mother child cohort of 588 pairs lead to a significant reduction of enamel defects.
Enamel defects was found in 28% of children by age 6 after standard dose of vitamin D supplementation (400 i.u.), compared to 15% after 7-fold higher dose vitamin D.(more…)
MedicalResearch.com Interview with:
Mitsuyoshi Urashima MD, PhD, MPH
Professor of Molecular Epidemiology
Jikei University School of Medicine
Tokyo, JAPAN
MedicalResearch.com: What is the background for this study? Response: Serum levels of vitamin D, increase in response to exposure to sunlight, a vitamin D-rich diet, or vitamin D supplementation. In 1989, the risk of colon cancer was estimated to be 70% lower in people with serum vitamin D levels ≥ 20 ng/mL, compared with those < 20 ng/mL.
In a cohort study, higher vitamin D levels were associated with lower total cancer incidence and lower total cancer mortality, particularly digestive system cancer mortality. However, because of the studies’ observational nature, whether lower levels of vitamin D is merely a precursor to relapse and death or causally related to shorter survival cannot be determined.
To clarify this, a randomized, double-blind, placebo-controlled trial using vitamin D supplement was performed in patients with digestive tract cancer from esophagus to rectum; this is the first trial designed to evaluate the effect of vitamin D on survival of these patients.(more…)
MedicalResearch.com Interview with:Bo Chawes, MD, PhD, DMSc
Associate Professor
Copenhagen Prospective Studies on Asthma in Childhood
Herlev and Gentofte Hospital
University of Copenhagen
MedicalResearch.com: What is the background for this study? What are the main findings?Response: There has been a global surge in vitamin D deficiency happening in parallel with an increase in prevalence of childhood asthma, which suggests that low maternal vitamin D levels during pregnancy may increase asthma risk in the child.
Due to that we conducted a randomized double-blinded controlled trial within the Danish COPSAC2010 cohort (www.copsac.com) of 7-fold (2,800 IU/d) vs. standard dose (400 IU/d) of vitamin D supplementation from pregnancy week 24 aiming to reduce offspring asthma risk. At age 3, we observed a non-significant 24% reduced risk of recurrent asthma-like symptoms, ie. recurrent wheeze, in the high-dose vitamin D group. In the current study, we followed 545 of the 581 children in the study till age 6, where an asthma diagnosis can be established and observed no effect of the high-dose vitamin D supplement on the child's risk of asthma.(more…)
MedicalResearch.com Interview with:
Professor Adrian Martineau, B Med Sci DTM&H MRCP PhD FRSB
Clinical Professor of Respiratory Infection and Immunity
Queen Mary
University of London
MedicalResearch.com: What is the background for this study? What are the main findings?Response: The World Health Organisation estimates that 10.0 million people developed active tuberculosis in 2017, and that 1.6 million people died of this disease. Multi-drug resistant (MDR) TB is caused by bacteria that are resistant to treatment with at least two of the most powerful first-line anti-TB drugs, causing around 500,000 cases and 150,000 deaths per year worldwide. Existing antibiotic treatments for MDR TB are lengthy, costly and often toxic due to their serious side effects.
One novel approach to treating MDR TB is to complement antibiotic treatment by using therapies that boost the immune system’s ability to kill TB bacteria. Vitamin D – the sunshine vitamin – is known to help white blood cells to make natural antibiotic substances (antimicrobial peptides) that can punch holes in the cell membranes of TB bacteria. Several clinical trials have investigated the effects of adding vitamin D to antibiotic treatment for TB.
In this study we pooled data from 8 of these studies (1850 participants) and analysed them to see if some TB patients benefited more from adding vitamin D to their treatment regimen than others. We found that vitamin D accelerated clearance of TB bacteria from the lungs of patients who had MDR TB; this benefit was not seen in patients who had ‘standard’ drug-sensitive TB. (more…)
Tetsuo Shoji, MD, PhD. Department of Vascular Medicine Osaka City University Graduate School of Medicine Osaka Japan
MedicalResearch.com: What is the
background for this study? What are the
main findings?
Response: Vitamin D is known to be associated with health and disease of various organs such as bone, heart, brain, and others. Vitamin D is activated by the liver and kidneys to a hormone called 1,25-dihydroxyvitamin D which binds to vitamin D receptor in cells to exert its functions.
Vitamin D activation is severely impaired in patients with kidney disease requiring hemodialysis therapy, leading to mineral and bone disorder(MBD). Therefore, active form of vitamin D is one of the standard choices of treatment for MBD caused by kidney function loss.
Previous observational cohort studies showed that the use of active vitamin D in hemodialysis patients was associated with lower likelihood of all-cause death, cardiovascular death, and incident cardiovascular disease.Potentially cardio-protective effects of active vitamin D were shown by basic studies using cultured cells and animal models. Then, many nephrologists began to believe that active vitamin D is a “longevity hormone” or a “panacea” for kidney patients requiring dialysis therapy, although there was no evidence by randomized clinical trials.
To show evidence for it, we conducted a randomized clinical trial namedJ-DAVID in which 976 hemodialysis patients were randomly assigned to treatment with oral alfacalcidol or treatment without active vitamin D, and they were followed-up for new cardiovascular events during the four-year period. The risk of cardiovascular events was not significantly different between the two groups. The risk of all-cause death was not significantly different either.
To our surprise, the risk of cardiovascular event tended to be higher in the patients who continued treatment with active vitamin D than those who continued non-use of active vitamin D, although the difference was not statistically significant.
MedicalResearch.comInterview with: Professor John McGrath Niels Bohr Professor National Centre for Register-based Research Aarhus University Queensland Brain Institute University of Queensland Brisbane AustraliaQueensland Centre for Mental Health Research The Park Centre for Mental Health Australia
MedicalResearch.com: What is the background for this study? What are the main findings?
Response:We know that people born in winter and spring have an increased risk of later developing schizophrenia. But, we were not sure why. We know that vitaminD, the sunshine hormone, is more likely to be low in winter and spring, so wedeveloped a way to test for vitamin D in stored neonatal blood sample.
MedicalResearch.com Interview with:
Dr Mark J Bolland PhD
Bone and Joint Research Group
Department of Medicine
University of Auckland
New Zealand
MedicalResearch.com: What is the background for this study? Response: Vitamin D supplements have long been recommended for older people to treat or prevent osteoporosis.
Early evidence suggested vitamin D supplements might have benefits for musculoskeletal health, but more recent systematic reviews have reported no effect of vitamin D supplementation on fractures, falls or bone mineral density. Some authors have suggested that inadequate vitamin D doses might explain these null results.
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MedicalResearch.com Interview with:
Stephanie J. Weinstein, M.S., Ph.D.
Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics
National Cancer Institute, NIH MedicalResearch.com: What is the background for this study? Response: Vitamin D, known for its role in maintaining bone health, is hypothesized to lower colorectal cancer risk via several pathways related to cell growth and regulation. Previous prospective studies have reported inconsistent results for whether higher concentrations of circulating 25-hydroxyvitamin D, the accepted measure of vitamin D status, are linked to lower risk of colorectal cancer. The few randomized clinical trials of vitamin D supplementation and colorectal cancer completed thus far have not shown an effect; but study size, relatively short supplementation duration, and only moderate compliance may have contributed to their null findings.
To address inconsistencies in prior studies on vitamin D, and to investigate associations in population subgroups, we harmonized and analyzed participant-level data from over 5,700 colorectal cancer cases who had blood collected before colorectal cancer diagnosis, and 7,100 matched cancer-free controls. Study participants were drawn from 17 prospective cohorts from the United States, Europe, and Asia and were followed for an average of 5.5 years (range: 1 – 25 years). We used a single, widely accepted assay and laboratory for new vitamin D measurements and calibrated existing vitamin D measurements. In the past, substantial differences between assays made it difficult to integrate vitamin D data from different studies. Our novel calibration approach enabled us to explore risk systematically over the broad range of vitamin D levels seen internationally.(more…)
MedicalResearch.com Interview with:
Cedric F. Garland, Dr.P.H., F.A.C.E.
Adjunct Professor
Division of Epidemiology
Department of Family Medicine and Public Health
University of California San Diego
La Jolla, California 92093-0620
MedicalResearch.com: What is the background for this study? Response: Studies mapping death rates from female breast cancer in the US, the former USSR and Canada by Drs. Edward Gorham, and Frank and Cedric Garland revealed for the first time in history that death rates from breast cancer tracked latitude where people lived.
The rates were highest in the least sunny northern tier of states, lowest in the sunny southwest. This led these scientists to be the first to theorize that vitamin D prevents breast cancer” said study first author Sharon McDonnell. (more…)
MedicalResearch.com Interview with:
Dr Javeria Saleem PhD
Department of Public Health, Institute of Social and Cultural Studies, University of the Punjab, Lahore, Pakistan
Centre for Primary Care and Public Health, Blizard Institute, Barts and The London School of Medicine and Dentistry
Queen Mary University of London
London, United Kingdom
MedicalResearch.com: What is the background for this study? What are the main findings?Response: Severe acute malnutrition is the most extreme and visible form of undernutrition. Affected children have very low weight for their height and severe muscle wasting; they may also have swollen feet, face and limbs. Around 20 million children suffer from severe acute malnutrition worldwide of whom an estimated 1.4 million live in Pakistan. The condition is a major cause of death in children under 5 in Asia and Africa. The standard treatment is to give a high-energy, micronutrient enhanced paste called ready-to-use therapeutic food (RUTF).
Vitamin D deficiency has been reported to be a risk factor for severe wasting in children with severe acute malnutrition Ready-to-use therapeutic food contains relatively modest amounts of vitamin D. However, the effects of adding high-dose vitamin D to this standard treatment have not previously been evaluated.
We therefore did a clinical trial to assess whether high-dose vitamin D hastened recovery in 185 children aged 6-58 months who were receiving standard treatment for severe acute malnutrition in Southern Punjab, Pakistan. The 93 children in the active arm of the study received two doses of 5 mg vitamin D by mouth, while the 92 children in the control arm received placebo (a dummy medicine containing no vitamin D).
Our findings were very striking: after 2 months of treatment, the children who received high-dose vitamin D in addition to standard therapy had significantly better weight gain, and significantly better motor and language development, than those who received standard treatment alone.
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MedicalResearch.com Interview with:
Dr. Alex Krist, M.D., M.P.H.Dr. Krist is is a professor of family medicine and population health at Virginia Commonwealth University and active clinician and teacher at the Fairfax Family Practice residency.What is the background for these recommendation statements? What are the main findings?Response: Falls are the leading cause of injuries in adults age 65 and older and can lead to serious disability and even death. Bone fractures—which may result from a fall—can also cause serious disability and death in older adults.
The U.S. Preventive Services Task Force looked into the most recent evidence on the best ways to prevent falls and fractures in older adults. We found that clinicians should recommend exercise or physical therapy to help prevent falls by older adults who live at home and are at higher risk for falling.
Additionally, we concluded that taking a low dose of vitamin D and calcium does not help prevent fractures due to osteoporosis, but we don’t know if taking a higher dose is effective or not, so we are calling for more research.
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MedicalResearch.com Interview with:
Dr Jia-Guo Zhao
Tianjin Hospital
Department of Orthopaedic Surgery
Tianjin, China
MedicalResearch.com: What is the background for this study?
Response: The increased social and economic burdens for osteoporotic-related fractures worldwide make its prevention a major public health goal.
Calcium and vitamin D supplements have long been considered a basic intervention for the treatment and prevention of osteoporosis. Survey analysis showed that 30–50% of older people take calcium or vitamin D supplements in some developed countries. Many previously published meta-analyses, from the high-ranking medical journals, concluded that calcium and vitamin D supplements reduce the incidence of fracture in older adults. And many guidelines regarding osteoporosis recommend calcium and vitamin D supplements for older people. The final aim for these supplements is to prevent the incidence of osteoporotic-related fracture in osteoporosis management.
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MedicalResearch.com Interview with:
David Jolliffe, PhD
Centre for Primary Care and Public Health
Blizard Institute
Barts and the London School of Medicine and Dentistry
London
MedicalResearch.com: What is the background for this study? Response: Asthma affects more than 300 million people worldwide and is estimated to cause almost 400,000 deaths annually. Asthma deaths arise primarily during episodes of acute worsening of symptoms, known as attacks or ‘exacerbations’, which are commonly triggered by viral upper respiratory infections. Vitamin D is thought to protect against such attacks by boosting immune responses to respiratory viruses and dampening down harmful airway inflammation.
Several clinical trials have tested whether vitamin D supplementation might protect against asthma attacks, but individually their results are inconclusive. In the current study, we pooled raw data from 955 asthma patients who took part in 7 separate trials, which allowed us to answer two questions:
1, Does vitamin D protects against asthma attacks overall, when data from all trials are pooled?
2, Do people who have lower vitamin D levels to start with particularly benefit from supplementation?
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MedicalResearch.com Interview with:Jonathon Maguire MD MSc FRCPC
Scientist, Li Ka Shing Knowledge Institute
Staff Pediatrician, Department of Pediatrics, St. Michael’s Hospital
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Vitamin D has been hypothesized as being protective of seasonal viral upper respiratory tract infections. In this randomized clinical trial, high dose wintertime vitamin D supplementation (2000 IU/day) was compared with standard-dose vitamin D supplementation (400 IU/day) among 703 children. The number of laboratory confirmed viral upper respiratory tract infections was not statistically different between groups.
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MedicalResearch.com Interview with:Brent Richards, MD, MSc
Associate Professor of Medicine
William Dawson Scholar / FRQS Clinical Research Scholar
Departments of Medicine, Human Genetics, Epidemiology and Biostatistics McGill University
Senior Lecturer, King's College London (Honorary)
MedicalResearch.com: What is the background for this study? What are the main findings?Response: Some previous epidemiological studies have suggested that low vitamin D levels are associated with increased rates of asthma, atopic dermatitis—an itchy inflammation of the skin—and elevated levels of IgE, an immune molecule linked to atopic disease (allergies). In our study, we looked at genetic and health data on more than 100,000 individuals from previous large studies to determine whether genetic alterations that are associated with vitamin D levels predispose people to the aforementioned conditions.
We found no statistically significant difference between rates of asthma (including childhood-onset asthma), atopic dermatitis, or IgE levels in people with and without any of the four genetic changes associated with lower levels of 25-hydroxyvitamin D, the form of vitamin D routinely measured in the blood.
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MedicalResearch.com Interview with:
Robert Scragg, MBBS, PhD
School of Population Health
The University of Auckland
Auckland New Zealand
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Interest in a possible role for vitamin D deficiency as a risk factor for cardiovascular disease was stimulated by studies showing a seasonal variation in cardiovascular disease, which is much higher in winter, when body levels of vitamin D are low, than in summer.
Main findings are that bolus monthly doses of vitamin D supplementation do not prevent against cardiovascular disease, even in people with low levels of vitamin D.
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MedicalResearch.com Interview with:
Joan M. Lappe, Ph.D., R.N., F.A.A.N.
Associate Dean for Research, College of Nursing
Criss/Beirne Professor of Nursing
Professor of Medicine
Creighton University
Omaha NE 68131
MedicalResearch.com: What is the background for this study? What are the main findings?
Numerous observational studies show that higher vitamin D intake and serum 25, hydroxyvitamin D [25(OH)D], the functional indicator of vitamin D status, are associated with lower incidence of cancer.
However, the scientific fields consider randomized clinical trials (RCT) as a gold standard for testing new interventions for prevention and treatment of disease. In the only RCT of cancer and vitamin D to date with cancer as a primary outcome, the Women’s Health Initiative, postmenopausal women randomly assigned to vitamin D3400 IU/day and calcium 1000 mg/day showed no difference from those assigned to placebo in colorectal cancer incidence. One criticism of that study was that the vitamin D intervention was low, only 400 international units (IU) per day.
In our study we found that, in healthy women ages 55 and older with a mean baseline serum 25(OH)D of 33 ng/mL, supplementation with 2000 IU/day of vitamin D3and 1500 mg/day of calcium for four years, compared with placebo, decreased all-type cancer incidence by about 30%, but this did not reach statistical significance. (p value =0.057 and for statistical significance, the p value would need to be less than 0.05.)
In a secondary analysis, we re-analyzed the data excluding cancers that developed during the first year of study and were likely present but not diagnosed upon study enrollment. The findings here were that vitamin D and calcium did significantly decrease cancer risk by about 35%.
In another secondary analyses, we combined all of the serum 25(OH)D values to determine if higher levels were associated with lower cancer incidence. Here, higher serum 25(OH)D was significantly associated with lower cancer incidence. Persons with serum 25(OH)D of 55 ng/mL had a 35% lower risk of cancer than persons with serum 25(OH)D of 30 ng/mL. This is especially interesting since current recommendations for sufficient serum 25(OH)D levels are 20 ng/mL (the National Academy of Medicine) and 30 ng/mL (the Endocrine Society).
Note that serum 25(OH)D is a better predictor of cancer development than assigning persons to supplement groups. Serum 25(OH)D takes into account poor compliance of the active supplement group with taking supplements, personal use of supplements by the placebo group, dietary vitamin D intake, sunlight exposure, and the variation among persons in absorption and metabolism of the vitamin D supplement.
MedicalResearch.com Interview with:Dr. Sheila Sprague, PhD
Assistant Professor, Research Methodologist
McMaster University
MedicalResearch.com: What is the background for this study? What are the main findings?Response: Previous research has found that daily administration of vitamin D is important for maintaining bone homeostasis. There has been an increased interest among the orthopaedic community regarding vitamin D supplementation and patient outcomes following fractures. Using data from the FAITH trial (NCT01908751), a multicenter randomized controlled trial that compared cancellous screws versus sliding hip screws in patients over the age of 50 with femoral neck fractures, we:
1) determined the proportion of patients consistently taking vitamin D following hip fracture surgery and
2) determined if supplementation was associated with improved health related quality of life and reduced re-operation.
Patients enrolled in the FAITH trial were recruited from 81 clinical sites in 8 countries over a 6-year span. We asked a subset of them about vitamin D supplementation and categorized them as consistent users, inconsistent users, or non-users.
The final analysis included 573 patients and we found that a surprisingly low proportion of elderly hip fracture patients are consistently taking vitamin D (18.7% of patients reported never taking vitamin D, 35.6% reported inconsistent use, and 45.7% reported consistent use). We also found that vitamin D was associated with a statistically (p=0.033), but not clinically, significant improvement in health-related quality of life following a hip fracture. Lastly, supplementation was discovered to not be associated with reduced re-operation (p=0.386).
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MedicalResearch.com Interview with:
Audry H. Garcia PhD
Scientist Department of Epidemiology
Erasmus MC, University Medical Center Rotterdam
Rotterdam, the NetherlandsMedicalResearch.com: What is the background for this study?
Response: Fetal bone mineralisation requires an adequate transfer of calcium to the fetus by the end of the pregnancy. Considering that vitamin D is required to maintain normal blood concentrations of calcium, adequate 25-hydroxyvitamin D (25[OH]D) concentrations in pregnant women seem to be crucial for bone development of the offspring. Maternal vitamin D deficiency during pregnancy has been associated with abnormal early skeletal growth in offspring and might be a risk factor for decreased bone mass in later life.Several studies have linked vitamin D deficiency in fetal life to congenital rickets, craniotabes, wide skull sutures and osteomalacia. However, the evidence of long-lasting effects of maternal vitamin D deficiency during pregnancy on offspring’s skeletal development is scarce and inconsistent, and has led to contradictory recommendations on vitamin D supplementation during pregnancy.
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MedicalResearch.com Interview with:
Dr. Adrian R Martineau
B Med Sci DTM&H MRCP PhD
Clinical Professor of Respiratory Infection and Immunity
Centre for Primary Care and Public Health.
Blizard Institute, Barts and The London School of Medicine and Dentistry
Queen Mary, University of London
MedicalResearch.com: What is the background for this study?
Response: In addition to its well-known effects on bone, Vitamin D has also been shown to boost immune responses to viruses and bacteria that cause respiratory infections in lab experiments.
In order to see whether these effects translate into a health benefit, a total of 25 clinical trials of vitamin D supplementation to prevent various respiratory infections have been carried out in around 11,000 people living in 14 different countries over the last decade.
These trials have yielded conflicting results: in some, vitamin D reduced the risk of infections, but in others it did not.
The reason why vitamin D ‘worked’ in some trials, but not in others, has been the subject of much debate.
In order to answer this question, we assembled an international consortium of investigators and compiled the raw data from every trial into a single database containing information from 10,933 people in total. This allowed us to run sub-group analyses to determine whether particular groups of people benefit more from vitamin D supplementation than others.
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MedicalResearch.com Interview with:MedicalResearch.com: What is the background for this study? What are the main findings?Response: Formation of vitamin D in the skin with UVB light from the sun is a main source of vitamin D during summer months, but in the winter months the UVB light is too weak for vitamin D production. Headache prevalence has been suggested to be related to increasing latitude (less UVB light throughout the year) and possibly to be less prevalent during summer (more UVB light), which suggests a possible role for vitamin D exposure.
Some previous small studies have suggested that low serum vitamin D levels might be associated with more frequent headache or migraine. Our study included 2601 men from the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) from eastern Finland, aged 42-60 years in 1984-1989, which makes it one of the largest studies so far regarding vitamin D and headache.
In our study chronic headache (occurring weakly or daily) was reported by 250 men, and men reporting chronic headache had lower serum vitamin D levels than others.
When we divided the study population into four groups based on their serum vitamin D levels, the group with the lowest levels had over a twofold risk of chronic headache in comparison to the group with the highest levels. Chronic headache was also more frequently reported by men who were examined outside the summer months of June through September.
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MedicalResearch.com Interview with:
Bo (Bonnie) Qin, Ph.D.
Post-Doctoral Associate
Rutgers Cancer Institute of New Jersey
New Brunswick, NJ 08903
MedicalResearch.com: What is the background for this study? Response: Ovarian cancer is the leading cause of death from gynecologic cancer in the US. African-American patients diagnosed with ovarian cancer tend to have a worse 5-year survival rate compared to their European-American patients. Therefore, identifying preventive factors in African-Americans women is particularly important.
African Americans tend to consume less calcium and vitamin D from dietary sources, due to a higher prevalence of lactose intolerance, and supplemental intake. Meanwhile, darker color of the skin reduces the synthesis of vitamin D upon sun exposure. They together place African-American women at risk for calcium and vitamin D deficiency. It remains unknown whether calcium, vitamin D, lactose and dairy products are associated with ovarian cancer risk in African-American women and our study aimed to answer this question.
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MedicalResearch.com Interview with:
Dr. Elisa Benetti PhD
Department of Drug Science and Technology
University of Turin
Turin, Italy
MedicalResearch.com: What is the background for this study?
Response: The idea for this study comes from the debate on the role of vitamin D supplementation in the prevention or progression of type 2 diabetes (T2DM). Epidemiological data point at a strong association between vitamin D deficiency and T2DM prevalence, however a causal relationship is still lacking.
Here we wanted to explore the effect of vitamin D administration on insulin-sensitivity, particularly focusing on skeletal muscle, which is a crucial tissue in the maintenance of glucose homeostasis and which was suggested to be a tissue target of vitamin D.
Using a murine model of insulin-resistance induced by a High Fat-High Sugar Diet (HFHS), we demonstrated that a vitamin D supplementation (7 μg•kg-1, i.p. three times/week) was able to revert the deleterious effects evoked by the diet, including the increase in body weight and in the HOMA-IR (a parameter of insulin resistance) and the glucose tolerance impairment. Consistently, at the muscle level, vitamin D increased the insulin sensitivity by reducing tissue inflammation and fat accumulation (myosteatosis).
These effects are due, at least in part, to the inhibition exerted by vitamin D on carboxymethyl-lysine (CML) production, one of the main Advanced Glucose End-products (AGEs), and on its receptor RAGE.
Collectively, our data indicate the ability of vitamin D to reduce the development of muscle insulin resistance, the primary defect in T2DM patients.
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MedicalResearch.com Interview with:Dr. Ben Wheeler MB ChB(Otago) DCH CCE FRACP
Senior Lecturer / Paediatrician / Paediatric Endocrinologist
Department of Women’s & Children’s Health : Te Tari Hauora Wāhine me te Tamariki
Dunedin School of Medicine
MedicalResearch.com: What is the background for this study?Response: Vitamin D is essential for calcium and bone metabolism. It is unique among vitamins in that it is mainly derived from synthesis in the
skin after exposure to UV-B radiation. In the absence of fortification, few foods are rich in vitamin D, including human milk, which contains very low amounts. Breastfeeding infants in higher latitude countries such as New Zealand, much of North America and
Central/Northern Europe are at risk of vitamin D deficiency.
The most profound manifestation of vitamin D deficiency in growing children is rickets, characterized by bone deformities, impaired growth, biochemical abnormalities, and depending on the severity of deficiency, seizures. Studies also identified a number of common factors that potentially affect the risk of rickets, including darker pigmented skin, maternal vitamin D deficiency during pregnancy, season of birth, and age.
A potential alternative strategy to improve the vitamin D status of breastfed infants is high-dose vitamin D supplementation to pregnant and lactating women. This would be attractive from a compliance perspective, promote exclusive breastfeeding, and treat both the mother and her infant.
Thus, the primary aim of this randomized, placebo-controlled study was to determine the effect of two different monthly doses of maternal vitamin D supplementation on the vitamin D status of non–vitamin D–supplemented breastfed infants and their mothers.
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MedicalResearch.com Interview with:Quaker Harmon M.D., Ph.D.
Epidemiology Branch
National Institute of Environmental Health Sciences
Research Triangle Park, NC 27709
MedicalResearch.com: What is the background for this study? What are the main findings?Response: Vitamin D is important for bone health. In the United States many women are vitamin D deficient. Vitamin D does not naturally occur in many foods, however some foods are fortified with vitamin D. Supplements and sunshine are the most reliable sources of vitamin D.
Previous studies suggested that women using birth control pills containing estrogen had higher levels of vitamin D. These studies were generally small and were not always able to examine important factors such as time spent outside. We were interested in examining the association between hormonal contraception and vitamin D levels in a larger group of women.
We found that women who use estrogen-containing contraception had a 20% increase in their vitamin D levels. This increase was not due to time spent outside or behaviors related to choice of contraception. The magnitude of increase for hormonal contraception was smaller than for regular use of a supplement containing vitamin D.
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MedicalResearch.com Interview with:Gerard (Gary) Hardiman, Ph.D
Professor, Department of Medicine Professor
Department of Public Health Sciences Bioinformatics Director
Center for Genomic Medicine Medical
University of South Carolina
Charleston, SC 29425
MedicalResearch.com: What is the background for this study? What are the main findings?Response: There are significant racial disparities in prostate cancer outcomes. The disease disproportionately affects African American men in terms of incidence, morbidity, and mortality, even after adjustment for stage. African American men have a 2- to 3-times increased risk of developing prostate cancer and have a greater mortality rate compared to European American men. We carried out a prospective clinical study aimed at examining the effects of vitamin D3 supplementation at 4,000 IU per day for two months in male subjects who selected surgical removal of the prostate (prostatectomy) as a definitive treatment for their prostate cancer. The primary goal of this study was to examine molecular differences in gene expression patterns relevant to prostate cancer disparities between African American and European American men, and investigate the global effects of vitamin D3 supplementation on the prostate transcriptome. We carried out genome wide expression profiling experiments using high throughput (HT) RNA sequencing. Transcriptional profiles of each of the patient’s tissue samples were generated and systems level analyses were performed.
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