Tag: vitamin D

Five Years of High-dose Vitamin D Reduced Atrial Fibrillation Risk

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Taking higher-than-recommended doses of vitamin D for five years reduced the risk of atrial fibrillation in older adults, according to a randomised controlled study conducted in Finland and published in the American Heart Journal.

Atrial fibrillation is the most common arrhythmia, the risk of which increases with age, and which is associated with an increased risk of stroke, heart failure and mortality. Vitamin D has been shown to have an effect, for example, on the atrial structure and the electrical function of the heart, suggesting that vitamin D might prevent atrial fibrillation.

Conducted at the University of Eastern Finland in 2012–2018, the main objective of the Finnish Vitamin D Trial (FIND) was to explore the associations of vitamin D supplementation with the incidence of cardiovascular diseases and cancers. The five-year study involved 2 495 participants, men aged 60 and older, and women aged 65 and older, who were randomised into three groups: one placebo group and two vitamin D3 supplementation groups, with one of the groups taking a supplement of 40µg (1600 IU) per day, and the other a supplement of 80µg (3200 IU) per day. All participants were also allowed to take their personal vitamin D supplement, up to 20µg (800 IU) per day, which at the beginning of the study was the recommended dose for this age group. Participants had no diagnoses of cardiovascular disease or cancer at baseline, and they completed comprehensive health-related questionnaires, both at the beginning. Data on the occurrence of diseases and deaths were also obtained from Finnish nationwide health registers. Approximately 20% of participants were randomly selected for more detailed examinations and blood samples.

During the five-year study, 190 participants were diagnosed with atrial fibrillation: 76 in the placebo group, 59 in the 40µg group, and 55 in the 80 micrograms group. The risk of atrial fibrillation was 27% lower in the 40µg group, and 32% lower in the 80 micrograms group, when compared to the placebo group. In the sub-cohort selected for more detailed examinations, the mean baseline serum calcidiol concentration, which is a marker of the body’s vitamin D concentration, was relatively high, 75nmol/l. After one year, the mean calcidiol concentration was 100nmol/L in the 40µg group, and 120nmol/l in the 80µg group. No significant change in the calcidiol concentration was observed in the placebo group.

Only two randomised trials tried to test whether vitamin D supplementation reduces AF risk in healthy adults, and they did not observe an effect when using doses of 10µg (400 IU) or 50µg (2000 IU) per day. Further confirmation of the present results from the FIND study is therefore needed before doses of vitamin D that significantly exceed current recommendations can be recommended for preventing atrial fibrillation. The FIND study has previously published findings showing no association with the incidence of other cardiovascular events or cancers.

Source: University of Eastern Finland

Low Maternal Vitamin D Levels may Increase Schizophrenia Risk of Offspring

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Neuroscientists published in the Journal of Neurochemistry, shows that maternal levels of vitamin D are key in the development of dopaminergic neurons, which are thought to be involved in schizophrenia.

Professor Darryl Eyles has built on past research out of his laboratory at the Queensland Brain Institute linking maternal vitamin D deficiency and brain development disorders, such as schizophrenia, to understand the functional changes taking place in the brain.

Schizophrenia is associated with many developmental risk factors, both genetic and environmental. While the precise neurological causes of the disorder are unknown, what is known is that schizophrenia is associated with a pronounced change in the way the brain uses dopamine, the neurotransmitter often referred to as the brain’s ‘reward molecule’.

Professor Eyles has followed the mechanisms that might relate to abnormal dopamine release and discovered that maternal vitamin D deficiency affects the early development and later differentiation of dopaminergic neurons.

The team at the Queensland Brain Institute developed dopamine-like cells to replicate the process of differentiation into early dopaminergic neurons that usually takes place during embryonic development.

They cultured the neurons both in the presence and absence of the active vitamin D hormone. In three different model systems they showed dopamine neurite outgrowth was markedly increased. They then showed alterations in the distribution of presynaptic proteins responsible for dopamine release within these neurites.

“What we found was the altered differentiation process in the presence of vitamin D not only makes the cells grow differently, but recruits machinery to release dopamine differently,” Professor Eyles said.

Using a new visualisation tool known as false fluorescent neurotransmitters, the team could then analyse the functional changes in presynaptic dopamine uptake and release in the presence and absence of vitamin D.

They showed that dopamine release was enhanced in cells grown in the presence of the hormone compared to a control.

“This is conclusive evidence that vitamin D affects the structural differentiation of dopaminergic neurons.”

Leveraging advances in targeting and visualising single molecules within presynaptic nerve terminals has enabled Professor Eyles and his team to further explore their long-standing belief that maternal vitamin D deficiency changes how early dopaminergic circuits are formed.

The team is now exploring whether other environmental risk factors for schizophrenia such as maternal hypoxia or infection similarly alter the trajectory of dopamine neuron differentiation.

Eyles and his team believe such early alterations to dopamine neuron differentiation and function may be the neurodevelopmental origin of dopamine dysfunction later in adults who develop schizophrenia.

Source: University of Queensland

Daily Vitamin D Could Reduce Cancer Mortality

Vitamin D intake could reduce cancer mortality in the population by 12% – provided the vitamin is taken daily. This was the result of an evaluation of 14 studies of the highest quality conducted at the German Cancer Research Center with a total of almost 105 000 participants.

Vitamin D deficiency is widespread worldwide and is particularly common among cancer patients. Averaged over the year, the vitamin D blood levels of about 15% of German adults are below the threshold for a pronounced vitamin D deficiency*. In contrast, in a study of colorectal cancer patients, researchers diagnosed vitamin D3 deficiency in 59% of participants, which was also associated with unfavourable prognosis.

Potential effects of vitamin D supplementation and the development or prognosis of cancer have already been investigated in numerous studies. “Based on current studies, vitamin D3 supplementation probably does not protect against developing cancer, but it could reduce the likelihood of dying from cancer. However, previous studies on cancer mortality have yielded very different results, and we were interested in the reasons for this,” said Ben Schöttker, an epidemiologist at the German Cancer Research Center. “By re-evaluating all previous studies on the topic, we wanted to help produce robust results on this issue, which is so relevant to population health.

To investigate the effectiveness of vitamin D3 on cancer mortality in the population and on the survival of cancer patients, Ben Schöttker and colleagues conducted a systematic literature search that identified 14 studies with a total of nearly 105 000 participants. The researchers considered only studies of the highest quality whose participants had been randomly assigned to the vitamin D3 arm or the placebo arm.

When all 14 studies were pooled, no statistically significant results emerged. However, when the studies were divided according to whether vitamin D3 was taken daily in a low dose** or in higher doses administered at longer intervals**, a large difference was seen. In the four studies with the infrequent higher doses, there was no effect on cancer mortality. In contrast, in the summary of the ten studies with daily dosing, the researchers determined a statistically significant twelve percent reduction in cancer mortality.

“We observed this twelve percent reduction in cancer mortality after untargeted vitamin D3 administration to individuals with and without vitamin D deficiency. We can therefore assume that the effect is significantly higher for those people who are actually vitamin D deficient,” says Ben Schöttker. He explains the better efficacy of daily doses of vitamin D3 by the more regular bioavailability of the active agent, the hormone 1,25-dihydroxyvitamin D, which is only produced by reactions of vitamin D in the body and can presumably inhibit tumor growth.

A more detailed analysis of the studies with daily intake further revealed that people aged 70 and older benefited most from vitamin D3 therapy. In addition, the effect was most evident when vitamin D intake was started before the cancer diagnosis.

Hermann Brenner, epidemiologist and prevention expert at DKFZ, adds: “This work underlines the great potential of vitamin D3 administration in the prevention of cancer deaths. Regular intake at low doses** is associated with almost negligible risk and very low cost.”

* The threshold blood 25-hydroxyvitamin D level used for vitamin D deficiency was 30 nmol/L (= 12 ng/ml). If individuals with less severe vitamin D deficiency (blood 25-hydroxyvitamin D level < 50 nmol/L (= 20 ng/mL)) are added, slightly more than half of Germans have at least one deficiency. However, there are also guidelines that use other thresholds. Since the vitamin D level in the blood depends primarily on the tanning of the skin, this percentage also varies greatly with the seasons.

** In the studies, daily low doses were 400 to 4000 IU per day, and higher-doses administered at longer intervals were 60 000 to 120 000 IU once per month or less.

Source: German Cancer Research Center

Vitamin D may be Necessary for Effective Immunotherapy in Skin Cancer

3D structure of a melanoma cell derived by ion abrasion scanning electron microscopy. Credit: Sriram Subramaniam/ National Cancer Institute

Vitamin D has many effects on the body, including regulation of the immune system. New research indicates that for patients with advanced skin cancer, it may be important to maintain normal vitamin D levels when receiving immunotherapy in the form of immune checkpoint inhibitors. The findings are published in CANCER.

To see whether levels of vitamin D might impact the effectiveness of immune checkpoint inhibitors, investigators analysed the blood of 200 patients with advanced melanoma both before and every 12 weeks during immunotherapy treatment.

A favourable response rate to immune checkpoint inhibitors was observed in 56.0% of patients in the group with normal baseline vitamin D levels or normal levels obtained with vitamin D supplementation, compared with 36.2% in the group with low vitamin D levels without supplementation. Progression‐free survival in these groups was 11.25 and 5.75 months, respectively.

“Of course, vitamin D is not itself an anti-cancer drug, but its normal serum level is needed for the proper functioning of the immune system, including the response that anti-cancer drugs like immune checkpoint inhibitors affect,” said lead author Łukasz Galus, MD, of Poznan University of Medical Sciences, in Poland. “In our opinion, after appropriately randomised confirmation of our results, the assessment of vitamin D levels and its supplementation could be considered in the management of melanoma.”

Source: Wiley

Vitamin D Supplements may Ward off Dementia

Vitamin D pills
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Taking vitamin D supplements may help ward off dementia, according to a new, large-scale study published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.

Canadian and UK researchers explored the relationship between vitamin D supplementation and dementia in more than 12 388 participants of the US National Alzheimer’s Coordinating Center, who had a mean age of 71 and were dementia-free when they signed up.

The team found that taking vitamin D was associated with living dementia-free for longer, and they also found 40% fewer dementia diagnoses in the group who took supplements.

Of the group, 2696 participants progressed to dementia over ten years; amongst them, 2017 (75%) had no exposure to vitamin D throughout all visits prior to dementia diagnosis, and 679 (25%) had baseline exposure.

Professor Zahinoor Ismail, of the University of Calgary and University of Exeter, who led the research, said: “We know that vitamin D has some effects in the brain that could have implications for reducing dementia, however so far, research has yielded conflicting results. Our findings give key insights into groups who might be specifically targeted for vitamin D supplementation. Overall, we found evidence to suggest that earlier supplementation might be particularly beneficial, before the onset of cognitive decline.”

While Vitamin D was effective in all groups, the team found that effects were significantly greater in females, compared to males. Similarly, effects were greater in people with normal cognition, compared to those who reported signs of mild cognitive impairment – changes to cognition which have been linked to a higher risk of dementia.

The effects of vitamin D were also significantly greater in people who did not carry the APOEe4 gene, known to present a higher risk for Alzheimer’s dementia, compared to non-carriers. The authors suggest that people who carry the APOEe4 gene absorb vitamin D better from their intestine, which might reduce the vitamin D supplementation effect. However, no blood levels were drawn to test this hypothesis.

Previous research has found that low levels of vitamin D are linked to higher dementia risk. Vitamin D is involved in the clearance of amyloid in the brain, the accumulation of which is one of the hallmarks of Alzheimer’s disease. Studies have also found that vitamin D may provide help to protect the brain against build-up of tau, another protein involved in the development of dementia.

Co-author Dr Byron Creese, at the University of Exeter, said: “Preventing dementia or even delaying its onset is vitally important given the growing numbers of people affected. The link with vitamin D in this study suggests that taking vitamin D supplements may be beneficial in preventing or delaying dementia, but we now need clinical trials to confirm whether this is really the case. The ongoing VitaMIND study at the University of Exeter is exploring this issue further by randomly assigning participants to either take vitamin D or placebo and examining changes in memory and thinking tests over time.”

Source: University of Exeter

Vitamin D Supplements may Reduce Skin Cancer Risk

Melanoma cells. Source: National Cancer Institute.

Fewer cases of melanoma were observed among regular users of vitamin D supplements than among non-users, researchers in Finland found. People taking vitamin D supplements regularly also had a considerably lower risk of skin cancer, according to a study of nearly 500 people with increased skin cancer risk, which was published in Melanoma Research.

A key micronutrient, vitamin D may play a role in many diseases. Previous studies investigating the link between vitamin D and skin cancers, have been inconclusive or contradictory, but they mainly focussed on serum levels of calcidiol, which is a metabolite of vitamin D. Serum calcidiol levels have been associated with both a slightly higher or lower risk of different skin cancers. This may be partly due to the fact that serum calcidiol analyses do not provide information on vitamin D metabolism in the human skin, which can express enzymes that generate biologically active vitamin D metabolites or inactivate them.

The new study took a different approach: 498 adult patients with an increased risk of a skin cancer, such as basal cell carcinoma, squamous cell carcinoma or melanoma, were recruited and classified into low risk, moderate risk and high risk. Based on their use of oral vitamin D supplements, the patients were divided into three groups: non-users, occasional users and regular users. Serum calcidiol levels were analysed in half of the patients and found to correspond to their self-reported use of vitamin D.

A key finding of the study is that there were considerably fewer cases of melanoma among regular users of vitamin D than among non-users, and that the skin cancer risk classification of regular users was considerably better than non-users’. Logistic regression analysis showed that melanoma risk among regular users was more than halved compared to non-users.

The findings suggest that even occasional users of vitamin D may have a lower risk for melanoma than non-users. However, there was no statistically significant association between the use of vitamin D and the severity of photoaging, facial photoaging, actinic keratoses, nevus count, basal cell carcinoma and squamous cell carcinoma. Serum calcidiol levels were not significantly associated with these skin changes, either. Since the research design was cross-sectional, the researchers were unable to demonstrate a causal relationship.

Other relatively recent studies, too, have provided evidence of the benefits of vitamin D in melanoma, such as of the association of vitamin D with a less aggressive melanoma.

“These earlier studies back our new findings from the North Savo region here in Finland. However, the question about the optimal dose of oral vitamin D in order to for it to have beneficial effects remains to be answered. Until we know more, national intake recommendations should be followed,” Professor of Dermatology and Allergology Ilkka Harvima of the University of Eastern Finland notes.

Source: University of Eastern Finland

Vitamin D is no Help for Statin Muscle Pains, Study Finds

Vitamin D pills
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Some clinicians have recommended vitamin D supplements to ease the muscle aches of patients taking a statin, but a new study published in the journal JAMA Cardiology shows the vitamin appears to have no substantial impact.

While non-randomised studies have reported vitamin D to be an effective treatment for statin-associated muscle symptoms, the new study, which is the first randomised clinical trial to look at the effect of vitamin D on statin-associated muscle symptoms, was large enough to rule out any important benefits.

In the randomised, double-blind trial, 2083 participants took either 2000 units of vitamin D supplements daily or a placebo. The study found participants in both categories were equally likely to develop muscle symptoms and discontinue statin therapy.

Over 4.8 years of follow-up, statin-related muscle pain was reported by 31% of the participants assigned vitamin D and 31% assigned a placebo.

“We had high hopes that vitamin D would be effective because in our clinic and across the country, statin-associated muscle symptoms were a major reason why so many patients stopped taking their statin medication,” said senior author Dr Neil Stone, professor at Northwestern University. “So, it was very disappointing that vitamin D failed a rigorous test. Nevertheless, it’s important to avoid using ineffective treatments and instead focus on research that can provide an answer.”

Statins and vitamin D supplements are two of the most commonly used medications in American adults. About 30 to 35 million Americans are prescribed statins, and about half of the population aged 60 and older take a vitamin D supplement.

“We took advantage of a large placebo-controlled randomised trial to test whether vitamin D would reduce statin-associated muscle symptoms and help patients keep taking their statins,” said lead study author Dr Mark Hlatky, a professor of health policy and cardiovascular medicine at Stanford. “The placebo control in the study was important because if people think vitamin D is supposed to reduce their muscle pains, they just might feel better while taking it, even if vitamin D has no specific effect.”

Trial was a sub study within a larger clinical trial

The 2083 patients were among the larger cohort of participants in the VITamin D and Omega-3 Trial (VITAL), which randomised nearly 26 000 participants to double-blind vitamin D supplementation to determine whether it would prevent cardiovascular disease and cancer. This provided researchers a unique opportunity to test whether vitamin D reduces muscle symptoms among participants who initiated statins during the follow-up period of the larger VITAL trial. The mean age of the study participants was 67, and 51% were women.

“Randomised clinical trials are important because many very good ideas don’t work as well as we had hoped when they are put to the test,” Hlatky said. “Statistical associations do not prove a cause-and-effect relationship. Low levels of vitamin D are associated with many medical problems, but it turns out that giving people vitamin D does not generally fix those problems.”

For patients who report statin-associated muscle pains

Dr Stone noted that sometimes the secret for understanding patients who have difficulty with statins is analysing other medications they’re taking, determining whether or not they have associated metabolic or inflammatory conditions, counselling them on their ability to hydrate adequately and, importantly, discussing “pill anxiety.”

“For those who have difficulties with statins, a systematic appraisal by a physician with experience in dealing with these matters is still very important,” Stone said.

Source: Northwestern University

Study Links Vitamin D Deficiency to Premature Death

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New research in the  Annals of Internal Medicine provides strong evidence that vitamin D deficiency is associated with premature death, prompting calls for people to follow healthy vitamin D level guidelines.

The study by the University of South Australia found that premature mortality increased in line with the severity of Vitamin D deficiency.

First author and UniSA PhD candidate, Josh Sutherland, says that while vitamin D has been connected with mortality, it has been challenging to establish causal effects.

“While severe vitamin D deficiency is rarer in Australia than elsewhere in the world, it can still affect those who have health vulnerabilities, the elderly, and those who do not acquire enough vitamin D from healthy sun exposure and dietary sources,” Sutherland says.

“Our study provides strong evidence for the connection between low levels of vitamin D and mortality, and this is the first study of its kind to also include respiratory disease related mortality as an outcome.

“We used a new genetic method to explore and affirm the non-linear relationships that we’ve seen in observational settings, and through this we’ve been able give strong evidence for the connection between low vitamin D status and premature death.

“Vitamin D deficiency has been connected with mortality, but as clinical trials have often failed to recruit people with low vitamin D levels – or have been prohibited from including vitamin deficient participants – it’s been challenging to establish causal relationships.”

The Mendelian randomisation study (an alternative to the gold standard of a randomised controlled trial) evaluated 307 601 records from the UK Biobank. Low levels of vitamin D were noted as less than <25 nmol/L with the average concentration found to be 45.2 nmol/L. Over a 14-year follow up period, researchers found that the risk for death significantly decreased with increased vitamin D concentrations, with the strongest effects seen among those with severe deficiencies.

Senior investigator Professor Elina Hyppönen says more research is now needed to establish effective public health strategies that can help achieve national guidelines and reduce the risk of premature death associated with low vitamin D levels.

“The take-home message here is simple – the key is in the prevention. It is not good enough to think about vitamin D deficiency when already facing life-challenging situations, when early action could make all the difference,” Prof Hyppönen says.

“It is very important to continue public health efforts to ensure the vulnerable and elderly maintain sufficient vitamin D levels throughout the year.”

Source: University of South Australia

Wealth Divide, not Vitamin D, Explains Differing MS Rates

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Differences in vitamin D exposure have been thought to explain why people who live farther from the equator are more likely to develop multiple sclerosis (MS). But countries farther from the equator are also more likely to be wealthier. A new analysis published in Neurology shows that the amount a country spends on health care may help explain this relationship between MS and latitude.

According to study author Deanna Saylor, MD, MHS, the results suggest that MS rates may be greatly underestimated in low-income countries with lower health care spending, which means that people have less access to neurologists who have the expertise to diagnose MS and MRI scanners that are needed to make the diagnosis.

Researchers analysed data from scientific studies and databases to determine current rates of MS in 203 countries and territories. Countries were then grouped into world regions and by income levels.

Rates of MS varied by region and income level. For example, in high-income countries an average of 46 of every 100 000 people had MS, compared to 10 people per 100 000 in low-income countries. Health care spending per capita was $2805 for high-income countries, compared to $45 in low-income countries.

For each location, researchers examined gross domestic product per capita, current health expenditure per capita, income levels, the availability of brain scans to diagnose MS, the number of neurologists per capita and universal health care. They also reviewed lifestyle factors such as obesity and tobacco use.

Once the researchers adjusted the data for other factors that could affect the risk of MS, such as age and sex, they found that health care spending and latitude were strongly associated with MS rates. The research showed that, with every increase of one standard deviation in health expenditure per capita, a country’s MS prevalence increased by 0.49. Alternatively, with every increase of one standard deviation in latitude, a country’s MS prevalence increased by 0.65.

Researchers also found that health care spending explained some, but not all, of the link between latitude and MS. After adjusting for other factors, the link between latitude and MS decreased by more than 20% when health care expenditure per capita was considered.

The availability of universal health care was associated with rates of MS in all world regions, except Southeast Asia, with universal health care tied to higher rates of MS.

In high-income countries, rates of MS were linked to most factors, including gross domestic product per capita, current health expenditure per capita, and the number of neurologists, but not tobacco use and obesity or the number of MRI units per capita. However, in low-income countries, there were no associations with any of these factors, which may be explained by a lack of significant variation in data from these countries, Saylor said.

According to Dr Saylor, the finding that current health expenditure per capita was very strongly linked with national rates of MS further supports the hypothesis that greater investment in health care leads to more robust reporting of rates of MS. She also said the minimal links between rates of MS and lifestyle factors such as tobacco use and obesity run counter to prior assumptions that lifestyle and consumption behaviours explain the large portions of regional differences in reported rates of MS.

Dr Saylor said strategies are urgently needed for the accurate assessment of the burden of MS in low-income countries, and these lower reported MS can obscure the need for training and funding regarding MS.

A limitation of the study is that different data sources may have collected information during different time periods or used different methods, which could affect the accuracy of estimates.

Source: American Academy of Neurology

Chronic Inflammation Link to Low Vitamin D Explains Some Controversies

Vitamin D pills
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New genetic research shows a direct link between low vitamin D levels and high levels of inflammation, providing an important biomarker to identify people at higher risk of or severity of chronic illnesses with an inflammatory component, such as type 2 diabetes. The findings, published in the International Journal of Epidemiology, also helps to settle some of the controversies surrounding the ‘sunshine vitamin’.

The study drew on genetic data for 294 970 participants in the UK Biobank, using Mendelian randomisation to show the association between vitamin D and C-reactive protein levels, an indicator of inflammation.

University of South Australia’s Dr Ang Zhou, the study’s lead researcher, said that the findings suggest that boosting vitamin D in people with a deficiency may reduce chronic inflammation.

“This study examined vitamin D and C-reactive proteins and found a one-way relationship between low levels of vitamin D and high levels of C-reactive protein, expressed as inflammation.

“Boosting vitamin D in people with deficiencies may reduce chronic inflammation, helping them avoid a number of related diseases.”

The study also raises the possibility that having adequate vitamin D concentrations may mitigate complications arising from obesity and reduce the risk or severity of chronic illnesses with an inflammatory component, such as CVDs, diabetes, and autoimmune diseases.

Senior investigator and Director of UniSA’s Australian Centre for Precision Health, Professor Elina Hyppönen, said that these results offer an explanation for some of the controversies in reported associations with vitamin D.

“We have repeatedly seen evidence for health benefits for increasing vitamin D concentrations in individuals with very low levels, while for others, there appears to be little to no benefit.” Prof Hyppönen said.

“These findings highlight the importance of avoiding clinical vitamin D deficiency, and provide further evidence for the wide-ranging effects of hormonal vitamin D.”

Source: University of South Australia