Waikato research links low vitamin D levels to pneumonia deaths

11 May 2011

A New Zealand study looking at vitamin D levels in patients admitted to hospital with pneumonia has shown that patients with severe vitamin D deficiency are more likely to die from the disease.

Researchers at Waikato University collaborated with doctors at Waikato Hospital to study the blood samples of 112 patients all admitted to Waikato hospital with community acquired pneumonia during the winter.

They found that those with severe deficiency - 15% of patients – were more likely to die within a month, when compared to the group of patients with normal or slightly low vitamin D levels. The research findings are published in the journal Respirology this month.

Vitamin D is known to be involved in the innate immune response to infection and Dr Ray Cursons from Biological Sciences at Waikato University says this research enhances our understanding of the apparent importance of vitamin D in combating respiratory infections.

Patient age, sex, additional health conditions, other prognostic factors did not affect the research outcome. “However as an observational study we were not able to establish causal associations between vitamin D deficiency and mortality in these patients.”

At Waikato Hospital Dr Leong Leow did the clinical work with consultant and respiratory specialist Dr Noel Karalus. Dr Karalus says as yet they don’t know whether supplementing patients admitted to hospital with respiratory tract infections with vitamin D will alter outcome. “It may transpire that vitamin D helps us avoid infection rather than cure it once established.”

Co-author Dr Bob Hancox from Otago University, who also works at the Department of Respiratory Medicine at Waikato Hospital says the improved understanding of vitamin D and its role in immunity may eventually lead to better ways to prevent and treat pneumonia.

“We now need to investigate whether vitamin D supplements could be a useful addition to pneumonia treatment and whether using supplements could help to prevent or reduce the severity of pneumonia among high-risk populations.”

Dr Cursons says the best source of vitamin D is sunlight as dietary sources such as fatty fish and cod liver oil do not include enough vitamin D.

“There is still some controversy regarding the optimal daily allowance of vitamin D. How much we absorb through the skin depends on sun exposure, skin type and geographical latitude. Māori and Pacific Islanders absorb less because of their darker skin, and people in colder climates also have lower levels of vitamin D.”

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