40% of Victorians have low Vitamin D levels

A study of 30,000 Victorians reveals 40% have low vitamin D levels, with serious health consequences.

Low levels of vitamin D have been linked to poor health consequences – from weaker bones to common conditions like diabetes and high blood pressure, as well as certain cancers.  In recent years a large body of literature has found links between vitamin D deficiency and autoimmune diseases such as multiple sclerosis (MS).

Now, a landmark study of vitamin D levels in over 30,000 Victorians attending a large Melbourne hospital between 2014 and 2017 found that only 40% of patients had levels of vitamin D that are adequate for good health. Importantly, two-thirds of men failed to have sufficient vitamin D levels.

There is growing interest in vitamin D and increasing public awareness. This is reflected in 128-fold increase in testing of serum vitamin D in 10 years. Also, Medicare costs for vitamin D testing have increased from $1M in the early 2000s to over $140M by 2012.

Despite increased testing, the optimal level of vitamin D for various age groups and various patient populations remains unknown. The study – the first large scale of Victorian patient groups – indicates that there is a serious vitamin D deficiency in certain patient groups, which can have long term health complications.

The study, which is a large collaborative effort between  Monash University, The Royal Melbourne Hospital and The University of Melbourne is published in the British Medical Journal.

According to Dr Mastura Monif, from Monash University’s Department of Neuroscience, and a lead researcher on the paper, it is now widely accepted that adequate vitamin D levels should be maintained in all life stages, from foetal development to old age. Low vitamin D status has been associated with an increased risk of rickets, osteoporosis, diabetes mellitus, cardiovascular disease, depression, autoimmunity and even pregnancy complications.

Low prenatal and early life vitamin D levels may also increase susceptibility to schizophrenia and multiple sclerosis (MS) in later life. In the elderly, higher risk of vitamin D deficiency and lower vitamin D status have been reported to be associated with increased fall risk.

“Although variation in vitamin D levels has been addressed in several studies across different countries and geographical latitude, studies of vitamin D status in Victorian patient population are lacking. Our clinical and research interests are in determining the role of vitamin D in autoimmune conditions such as Multiple Sclerosis; hence it’s imperative that more research is conducted not only looking at the population level but also at the cellular/ molecular paradigms,” Dr Monif said.

The study, performed by Ms Veronica Voo as part of her Masters studies, found that only 36.8% of the patient population were sufficient in vitamin D, and that the lowest mean vitamin D level in all patients occurred in winter. Although patients from Neurology specialty had the highest average vitamin D concentration, only 40.6% were sufficient in vitamin D levels.

Interestingly, the study found that 57% of women in the study were lacking in vitamin D while two-thirds of men were vitamin D deficient, which puts Victoria at odds with the rest of Australia where studies have found that more women than men in the rest of the country have lower vitamin D levels.

The study also found that, as Victorians get older, their vitamin D levels increase. “This is likely because of an increased uptake of supplements by older people,” according to Ms Veronica Voo. So from this perspective, maybe the public health measures are working.

According to Dr Monif, the recommendations for vitamin D levels can vary depending on the clinical scenario, but she said that a value of 75-100nmol/L in patient populations is generally aimed for.

Ms Voo is now a PhD student supervised by Dr Monif, and her next study during her PhD will examine vitamin D status in MS relapse and in response to MS treatment.

Reference: Voo VTF, Stankovich J, O'Brien TJ, Butzkueven H, Monif M. Vitamin D status in an Australian patient population: a large retrospective case series focusing on factors associated with variations in serum 25(OH)D. BMJ Open. 2020 Mar 4;10(3):e032567. doi: 10.1136/bmjopen-2019-032567.