A new study reveals the importance of vitamin D for heart health

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Vitamin D status can help assess cardiovascular risk. Cyndi Monaghan/Getty Images
  • Vitamin D, also known as the “sunshine” vitamin, is a fat-soluble vitamin that comes in two main forms: D-2 and D-3.
  • Vitamin D is an essential micronutrient obtained primarily from sunlight and is important for bone and tooth development and the regular functioning of the immune system.
  • In addition to these features, previous studies suggest a link between low vitamin D levels and a greater chance of developing cardiovascular disease.
  • In a new study, researchers have found it worth checking vitamin D levels when assessing a person’s cardiovascular risk.

Worldwide, cardiovascular disease (CVD) are one of the leading causes of death. Each year, an estimated 17.9 million people worldwide die from complications from heart disease. For context, this means that cardiovascular disease is responsible for 32% of all deaths worldwide.

Prior studies show that several factors – such as different health conditions, age, family history, diet and lifestyle – together influence the risk of developing CVD.

Using a new analytical approach, researchers in Australia have discovered an additional factor that can increase a person’s risk of cardiovascular disease.

Lead author Prof. Elina Hyppönen, director of the Australian Center for Precision Health at the University of South Australia Cancer Research Institute, outlined the results of the study for Medical news today,

“We found evidence that vitamin D deficiency can increase blood pressure and the risk of CVD.”

“However,” she added, “increasing vitamin D concentrations will only be beneficial to those participants who ‘need it,’ and further benefits of increasing concentrations above the nutritional requirement will be modest, if they to exist.”

The results of the study appear in the European Heart Journal.

In the recent study, the researchers wanted to investigate whether there is a link between serum 25-hydroxyvitamin D, or 25(OH)D, and the risk of developing CVD.

Serum 25(OH)D levels are an established marker of vitamin D status.

To test their hypothesis, the researchers used a specific analytical method to analyze data from UK Biobank – a large prospective cohort study of the UK population aged 37-73.

The participants were recruited from 22 assessment centers in the United Kingdom between 13 March 2006 and 1 October 2009. They filled out questionnaires that provided general information about health and lifestyle at baseline and provided blood samples for biomarker and genetic testing.

For the study, the research team limited the data analyzes to unrelated individuals who were identified as white British based on self-report and genetic profiling. In addition, the team excluded participants with information mismatches between self-reported and genetic sex.

After filtering, the research team performed genetic testing on individuals with complete information on 25(OH)D concentrations. As a safety measure, they also collected variables – including age, gender and time of sample collection – that could influence serum 25(OH)D measurements.

The scientists collected this information from up to 295,788 participants.

The researchers compared the results with those of a control group without a CVD diagnosis. The research team also conducted a secondary analysis to investigate the association of 25(OH)D concentration levels with blood pressure.

The researchers state that the average 25(OH)D concentration level among the 267,980 participants ultimately surveyed was 50 nanomoles per liter (nmol/l).

They also note that:

  • 11.4% (32,868) of participants had concentrations below 25 nmol/L
  • 41.3% (119,243) of participants had concentrations between 25 and 49.9 nmol/l
  • 35.3% (101,848) of participants had concentrations between 50 and 74.9 nmol/L
  • 10.5% (30,314) of the participants had concentrations between 75 and 99.9 nmol/l
  • 1.4% (4,110) of participants had concentrations between 100 and 124.9 nmol/l

Less than 0.1% of participants had a 25(OH)D concentration greater than 125 nmol/L.

Further analysis revealed that the individuals with serum 25(OH)D of 25 nmol/L had an 11% higher risk of CVD than those with concentrations of 50 nmol/L.

However, there appeared to be a reduction in the risk of developing cardiovascular disease at higher concentrations. For example, participants with concentrations of 75 nmol/l had a 2% lower chance of CVD compared to those with 50 nmol/l.

Scientists call this phenomenon a nonlinear association, where a change in the value of one entity does not always correspond to a constant change in the value of the other entity.

The researchers saw similar nonlinear associations in the relationship between 25(OH)D concentrations and the participants’ blood pressure levels. At 25 nmol/l there was a noticeable increase in blood pressure values ​​compared to 50 nmol/l.

The findings led the scientists to conclude that vitamin D deficiency may increase the risk of CVD.

To fully understand the implication of the results, MNT experts approached.

dr. Rigved Tadwalkar, a board-certified cardiologist at Providence Saint John’s Health Center in Santa Monica, CA, noted that the study has clinical implications.

He noted that there has long been confusion about whether or not to monitor vitamin D levels when assessing cardiovascular risk and what to do with the information after getting the results.

“[However, now], this study finds it worthwhile to monitor vitamin D levels for assessing cardiovascular risk and additionally for supplementing vitamin D for those most deficient.”

The authors explain that the strength of their research lies in the new way they analyzed their data. To their knowledge, the study is the first genetic analysis to use a nonlinear framework to examine the shape of the association of 25(OH)D with CVD risk.

In addition, through rigorous experimental practices, they were able to minimize biases and reduce accidental findings.

Despite its strengths, the study is not without its limitations. First, by limiting the analysis to participants of white British descent, it is not clear whether the study results apply to other ethnic groups.

Also, UK Biobank with a response rate of 5% is not representative of the general population of the UK, despite the large sample size.

Nevertheless, the results of the study may lead to new possibilities for the treatment and diagnosis of CVD.

dr. Tadwalkar’s latest comments on the study share a similar optimism:

“People should discuss checking their vitamin D levels with their doctors, as it varies from doctor to doctor whether this is routinely monitored. If vitamin D levels are found to be significantly low, there is now evidence that increasing of this level will reduce the risk of cardiovascular disease, including the risk of coronary artery disease and stroke.”

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