Vitamin D deficiency linked with cardiovascular disease risk, study finds

07 Dec 2021 --- Many people with deficient vitamin D intake have an increased risk of suffering from cardiovascular diseases (CVDs) compared to individuals with normal vitamin D levels.

This is according to a study from the University of South Australia that also found that vitamin D deficiency can lead to increased blood pressure.

Globally, CVD is the leading cause of death worldwide, resulting in an estimated 17.9 million deaths per year. In Australia, CVD accounts for one in four deaths and costs the Australian economy AUD$5 billion (US$3.55 billion) each year, more than any other disease.

“Understanding the connection between low levels of vitamin D and CVD is significant, given the global prevalence of this deadly condition,” says Elina Hyppönen, chief investigator and professor at the University of South Australia.

“Our results suggest that if we can raise levels of vitamin D within norms, we should also affect rates of CVD. In our study population, by increasing vitamin D-deficient individuals to levels of at least 50 nmol/L (nanomoles per liter), we estimate that 4.4% of all CVD cases could have been prevented.”

A global issue
The study authors note that low concentrations of vitamin D are common in many parts of the world, with data from the UK Biobank showing that 55% of participants have low levels of vitamin D (<50 nmol/L) and 13% have a severe deficiency (<25 nmol/L).Study participants with the lowest vitamin D concentrations had an increased risk of developing heart disease.

Considering this data, the Australian and New Zealand Bone and Mineral Society (ANZBMS) and Osteoporosis Australia (OA) guidelines classify vitamin D results as follows:

• 25-hydroxy-vitamin D of less than 30 nmol/L is deficient.
• 25-hydroxy-vitamin D of 30-50 nmol/L is mildly deficient.
• 25-hydroxy-vitamin D of greater than 50 nmol/L is sufficient for the health of bones.

Low vitamin D levels are recorded by an estimated 23% of people in Australia, 24% of people in the US and 37% of people in Canada.

“Severe deficiency is relatively rare, but in settings where this does occur, it is very important to be proactive and avoid negative effects on the heart. For example, deficiency can be a problem for people living in residential care who may have limited exposure to the sun,” explains Hyppönen.

“We can also get vitamin D from food, including oily fish, eggs and fortified foods and drinks. This said, food is, unfortunately, a relatively poor source of vitamin D, and even an otherwise healthy diet does not typically contain enough.”Understanding the role of vitamin D deficiency in heart health could help reduce the global burden of cardiovascular disease.

If the sun is not the primary source of vitamin D for an individual, then daily supplementation is needed to keep up with the requirements. A population-wide approach to eradicate vitamin D deficiency could reduce the global burden of CVD, she flags.

Taking a genetic approach
To ensure participants’ safety, the large-scale Mendelian study used a new genetic approach that allowed the team to assess how increasing levels can affect CVD risk based on how high the participants’ actual vitamin D levels were.

“It is not ethical to recruit people with vitamin D deficiency to a randomized controlled trial and to leave them without treatment for long periods. It is exactly this type of difficult setting that demonstrates the power of our genetic approach, given we can show how improving concentrations affects the risk in those most in need, without exposing participants to any harm,” adds Hyppönen.

The study used information from up to 267,980 individuals who allowed the team to provide statistical evidence for the link between vitamin D deficiency and CVD.

In taking a closer look at vitamin D deficiency, an Alborz University of Medical Sciences recent study found that the prevalence of the metabolic syndrome is higher in children with a vitamin D deficiency than those who are not deficient in the nutrient.

By Nicole Kerr