Author Interviews, JAMA, Orthopedics, Vitamin D / 26.12.2019

MedicalResearch.com Interview with: Robert Clarke MD, 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.
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Author Interviews, Calcium, Geriatrics, JAMA, Vitamin C / 05.01.2018

MedicalResearch.com Interview with: “ZMA och D-vitamin. Intages med dubbelsidig C-brus. #placebomannen” by Robin Danehav is licensed under CC BY 2.0Dr 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. (more…)
Alzheimer's - Dementia, Author Interviews, Calcium, Neurology / 19.08.2016

MedicalResearch.com Interview with: Silke Kern, MD, PhD Neuropsychiatric Epidemiology Unit and Clinical Neurochemistry Laboratory Department of Psychiatry and Neurochemistry Institute of Neuroscience and Physiology Sahlgrenska Academy University of Gothenburg Gothenburg, Sweden MedicalResearch.com: What is the background for this study? What are the main findings? Response: Calcium has an important role in ischemic neuronal cell death and atherosclerosis. Several studies suggest that increased serum calcium increases the risk for vascular events and worsens the outcome after stroke. Widespread ischemic neuronal cell death and atherosclerosis might lead to dementia. We therefore examined if Calcium supplementation is associated with development of dementia. Our study is the first to show a relationship between Calcium supplementation and increased risk for dementia in older women. This risk is mainly confined to women with cerebrovascular disease (history of stroke or presence of white matter lesions). (more…)
Author Interviews, Bone Density, Calcium, Mineral Metabolism, Nature / 16.08.2016

MedicalResearch.com Interview with: Dr. Constance Hilliard Department of History University of North Texas Denton, TX MedicalResearch.com: What is the background for this study? What are the main findings? Response: As an evolutionary historian, I have devoted the last several years to researching the health implications of genetic diversity. I was particularly concerned with the tendency of medical researchers to unwittingly use the biology of people with Northern European ancestry as a universal standard for everyone. For instance, lactose intolerance may be a disorder in that community, which suffers high rates of osteoporosis. But since 65% of the world’s population are lactose intolerant and have low rates of osteoporosis, a one-size-fits-all approach to bone health can prove dangerous for those whose ethnic-specific biological needs are overlooked. This study shows that osteoporosis is not a global problem. It has a strong and devastating impact in dairy-farming societies and is virtually non-existent in the tsetse zone of West Africa, where cattle rearing and dairying are not possible. Previous studies have tried to correlate the degenerative bone disease with socio-economic income. However, this study compares two regions of Africa with similar socio-economic conditions. In dairy-farming East Africa, the incidence of osteoporosis is 245 per 100,000. However in the tsetse belt of West Africa, where people do not consume dairy products, it is 3 per 100,000. When regression analyses are performed on 40 countries around the world, the association between dairy consumption and osteoporosis is high (0.851). It only correlates with national Gross National Product at a regression rate of 0.447. (more…)
Author Interviews, Calcium, Heart Disease / 02.04.2016

MedicalResearch.com Interview with: Dr. Chan Soo Shin MD PhD Professor of Medicine Seoul National University College of Medicine Seoul, 03080, Korea MedicalResearch.com: What is the background for this study? What are the main findings? Response: Recently, a series of secondary analyses on large clinical trials and meta-analysis have reveled increased rate of cardiovascular events in women allocated to calcium supplements. As most of these studies were conducted in Western countries where the dietary calcium intake is sufficient, we aimed to investigate the association between dietary calcium intake level and cardiovascular events or mortality in Korea where the average dietary calcium intake is as low as 470 mg per day. We have analyzed data from 4,866 adults aged at least 50 years without previous CDV or stroke history participating in the Ansung and Ansan cohort study, an ongoing, prospective, community-based study in Korea (2,690 women). Participants completed periodic food frequency questionnaires; CVD, stroke and fractures were recorded during interviews and examinations every 2 years. Researchers used proportional Cox regression analysis was used to determine HRs for all-cause mortality, CVD, cerebrovascular disease and fractures, adjusting for age, BMI, vegetable and fruit intake, protein and sodium intake, physical activity, smoking and drinking status, diabetes and hypertension history and total energy from diet. Researchers also adjusted for menopausal status and hormone replacement therapy in women. Women were followed for a mean of 9.2 years; men followed for a mean of 8.9 years. Within the cohort, 359 participants died (243 men); 340 developed CVD (153 men); 157 experienced stroke (59 men); 568 experienced incident fractures (212 men). In comparing the four quartiles for energy-adjusted calcium intake, women experienced an increased reduction in CVD risk with increasing dietary calcium intake. Women in the highest quartile saw the greatest reduced risk for CVD vs. the lowest quartile (HR = 0.53; 95% CI, 0.33-0.86), followed by women in the third (HR = 0.56; 95% CI, 0.36-0.85) and second quartiles (HR = 0.80; 95% CI, 0.55-1.17) when compared with women in the lowest quartile. We found no association between dietary calcium intake and stroke or fracture risk in women. Dietary calcium intake did not affect all-cause mortality, CVD risk, stroke risk or fracture risk in men. (more…)
Author Interviews, Calcium, Kidney Disease, Kidney Stones, Supplements, Vitamin D / 20.10.2015

MedicalResearch.com Interview with: Christopher Loftus M.D. candidate Cleveland Clinic Lerner College of Medicine Medical Research: What is the background for this study? What are the main findings? Response: Most kidney stones are made, at least partially, of calcium composite. In a prospective study of nurses in the post-menopausal age, it was found that diets that contained high amounts of calcium were beneficial in preventing kidney stones in this population. In the gut, calcium can bind to oxalate which prevents it from being absorbed into the body and decreases the concentration of calcium in the urine. However there has been debate as to whether supplemental calcium (calcium pills) has the same beneficial effects as calcium in the diet. Supplemental calcium enters the gut in large quantities all at once so it may enter the blood stream in higher concentrations over smaller amounts of time. By the same token, vitamin D plays a role in the management and balance of calcium in the body and could potentially have an effect on stone formation as well.  It has also been debated whether vitamin D supplementation has major effect on patients who are known to be stone formers.  So we reviewed CT scans of patients and 24 hour urine collections (both male and female of adult age) who were known to have kidney stones and measured the growth of stones over a period of time. Our main findings were that supplementary calcium increased the rate of stone formation in these patients. We also found that vitamin D had a protective effect and patients taking only vitamin D had a slower rate of stone progression. (more…)
Author Interviews, BMJ, Bone Density, Calcium, Mineral Metabolism, Orthopedics / 03.10.2015

MedicalResearch.com Interview with: Dr. Mark J Bolland Associate professor of medicine Department of Medicine University of Auckland Auckland New Zealand Medical Research: What is the background for this study? Dr. Bolland: Many guidelines advise older people to take at least 1000-1200 mg/day of calcium to improve bone density and prevent fractures. The average calcium intake in most countries is a lot less than these recommendations, and so many people take calcium supplements to increase their calcium intake. However, recent concerns about the safety of calcium supplements have led experts to recommend increasing calcium intake through food rather than by taking supplements, even though the effect of increasing dietary calcium intake on bone health had not been clearly established. Our study was designed to fill this evidence gap. Medical Research: What are the main findings? Dr. Bolland: Firstly, we found that increasing calcium intake either from the diet or by taking calcium supplements led to similar, small, one-off increases in bone density of 1-2%. These increases do not build up over time and are too small to produce significant reductions in the chance of having a fracture. Secondly, the level of dietary calcium intake is not associated with the risk of having a fracture. Thirdly, in clinical trials, calcium supplements have only small, inconsistent benefits on preventing fractures, with no effect on fractures seen in the highest quality trials (more…)
General Medicine / 26.09.2014

MedicalResearch.com Interview with: Dr Fergus Hamilton University of Bristol, Centre for Academic Primary Care, School of Social and Community Medicine, Canyngne Hall, Bristol UK. Medical Research: What are the main findings of the study? Dr. Hamilton: The findings of this study showed a stepwise increase in risk of cancer as calcium levels increase above the normal range, most notably in men. This relationship did occur in women, but was much less strong (more…)
Author Interviews, Diabetes, Diabetes Care / 03.09.2014

Jordi Salas-Salvadó MD PhD Physiopathology of Obesity and Nutrition Institute of Health Carlos III, Madrid, SpainMedicalResearch.com Interview with: Jordi Salas-Salvadó MD PhD Physiopathology of Obesity and Nutrition Institute of Health Carlos III, Madrid, Spain Medical Research: What are the main findings of the study? Dr. Salas-Salvadó: The main finding of our study is that an increase in albumin-adjusted serum calcium increases the risk of type 2 diabetes in Mediterranean individuals at high cardiovascular risk. This association remained significant even after taking classic risk factors into account. To the best of our knowledge this is the first study assessing the association between changes in serum calcium levels and the risk of type 2 diabetes development. (more…)
Author Interviews, Brigham & Women's - Harvard, Calcium, Heart Disease / 13.05.2014

Dr. Julie Paik, MD MPH Instructor, Harvard Medical School Brigham and Women's Massachusetts GeneralMedicalResearch.com Interview with: Dr. Julie Paik, MD MPH MSc Instructor, Harvard Medical School Brigham and Women's Hospital MedicalResearch: What are the main findings of the study? Dr. Paik: Many women in the United States take calcium supplements. One study found that over 60% of women aged 60 and over in the United States were taking calcium supplements. However, the medical community is still not certain of the effects of calcium supplements in women, particularly on cardiovascular disease risk. For this reason, we studied 74,245 women participating in the Nurses' Health Study over a 24-year follow-up period for their risk of developing cardiovascular disease (heart disease or stroke). We found that there was no increased risk of heart disease or stroke among women taking calcium supplements during the 24-year follow-up period. Our paper has several distinct strengths compared to prior studies including the large sample size, long follow-up period, cases of cardiovascular disease that were confirmed by medical record review, detailed and repeated assessment of calcium supplement use, and detailed information about other risk factors for cardiovascular disease. (more…)
Heart Disease, Vitamin D / 01.05.2014

Joshua Lewis, Ph.D Raine Foundation / Alan Robson Fellow Bone and Vascular Research Group School of Medicine and Pharmacology University of Western Australia Department of Endocrinology and Diabetes Sir Charles Gairdner HospitalMedicalResearch.com Interview with: Joshua Lewis, Ph.D Raine Foundation / Alan Robson Fellow Bone and Vascular Research Group School of Medicine and Pharmacology University of Western Australia Department of Endocrinology and Diabetes Sir Charles Gairdner Hospital MedicalResearch.com: What are the main findings of the study? Dr. Lewis: We tested the hypothesis raised by others that calcium supplementation with or without vitamin D increases coronary heart disease and mortality risk in elderly women. To do this we undertook a meta-analysis of published and unpublished data from patient level and cluster randomized controlled trials of calcium supplements with or without vitamin D in elderly women. Importantly all events included in this large meta-analysis were verified by clinical review, hospital record or death certificate. We did not observe any significant increase in all-cause mortality or coronary heart disease events that included myocardial infarction, angina pectoris and acute coronary syndromes and chronic coronary heart disease. (more…)
Author Interviews, NIH / 15.03.2014

Peter F. Schnatz, D.O. Associate Chair & Residency Program Director The Reading Hospital Department of OB/GYN Reading, PA 19612-6052MedicalResearch.com Interview with: Peter F. Schnatz, D.O. Associate Chair & Residency Program Director The Reading Hospital Department of OB/GYN Reading, PA  19612-6052 MedicalResearch.com: What are the main findings of the study? Dr. Schnatz: In a subsample of 576 women from the parent WHI CaD (calcium plus vitamin D supplementation)  trial* , there was a significant (38%) increase in mean serum 25OHD3 concentrations after two years (95% CI 1.29-1.47, p< 0.001) for women randomized to CaD (24.3ng/mL vs. 18.2 ng/mL). Women randomized to CaD had a 4.5 mg/dL mean decrease in LDL-C which was statistically significant.  After accounting for serum 25OHD3 concentration, the effect of CaD was attenuated, suggesting that higher concentrations of 25OHD3, in response to CaD supplementation, are associated with improved LDL-C. In observational analyses, higher concentrations of 25OHD3 were associated with significantly higher HDL-C along with significantly lower LDL-C and TG concentrations. * 1,000 mg of elemental calcium plus 400 IU of vitamin D3 daily (more…)
Author Interviews, Calcium, Gender Differences, Heart Disease / 09.11.2013

Joshua Lewis, Ph.D Raine Foundation / Alan Robson Fellow Bone and Vascular Research Group School of Medicine and Pharmacology University of Western Australia Department of Endocrinology and Diabetes Sir Charles Gairdner Hospital Hospital Avenue, Nedlands 6009MedicalResearch.com Interview with: Joshua Lewis, Ph.D Raine Foundation / Alan Robson Fellow Bone and Vascular Research Group School of Medicine and Pharmacology University of Western Australia Department of Endocrinology and Diabetes Sir Charles Gairdner Hospital Hospital Avenue, Nedlands 6009 www.boneandvascularresearch.org.au MedicalResearch.com: What are the main findings of the study? Dr. Lewis: The paper reports the findings from an ancillary study of the effects of 1200 mg per day of calcium supplementation on a major predictor of heart disease risk, carotid artery intima-medial thickness and atherosclerosis. The principle study was a large five-year double blind randomized controlled trial of calcium supplements or a placebo. After 3 years of calcium supplementation or placebo measures of carotid artery intima-medial thickness were identical in the placebo and calcium treated patients.  Atherosclerotic plaque was reduced in calcium treated patients when analysed as total calcium intake. These findings argue strongly against an adverse effect of high dose calcium tablets on cardiovascular risk. (more…)
Author Interviews, Calcium, Mineral Metabolism / 09.04.2013

 MedicalResearch.com eInterview with Maoquing Wang Department of Nutrition and Food Hygiene, School of Public Health, Harbin MedicalUniversity, 157 Baojian Road, Nangang District, Harbin, 150081, P. R. China MedicalResearch.com: What are the main findings of the study? Dr. Wang: Our group first reported that the 2-week low-calcium diet could result in metabolic changes and 27 reliable biomarkers of calcium deficiency were identified. The correlations between calcium intake and two of the biomarkers indicated that these biomarkers could be used alone or in combination as a non-invasive screening method with greater sensitivity and specificity for the diagnosis of calcium deficiency in humans in future. The identified biomarkers give new insights into the pathophysiological changes and molecular mechanisms of calcium deficiency. (more…)