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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

New meta-analysis adds clarity to the role of vitamin D in hospital mortality

A recent meta-analysis of over 4,000 participants found that vitamin D deficiency is associated with increased incidence of hospital mortality among critically ill adults.

Research has provided a large amount of evidence that indicates vitamin D deficiency is related to adverse health outcomes in critically ill patients, such as higher infection rates, prolonged length of stay, and hospital mortality.

However, a few studies from this past year have raised concerns regarding these findings. One cohort of 180 critically ill patients found no association between low vitamin D levels and increased mortality rates. This study suggested that those with vitamin D levels above 100 ng/ml experienced significantly higher mortality rates when compared to the other participants.

In June, Will Hunter covered a cohort study in which researchers found a u-shaped relationship between pre-hospital vitamin D status and mortality.

Given this conflicting evidence, researchers from China recently conducted a large meta-analysis to help clear up the conflicting research.

The researchers included seven cohort studies, three retrospective and four prospective cohorts, equaling a total of 4,204 participants into their meta-analysis. All cohorts focused on the relationship between vitamin D status and hospital or ICU mortality.

After analyzing the data, here is what they found:

  • Vitamin D deficiency was significantly associated with increased hospital mortality (p < 0.001).
  • Patients who were vitamin D deficient were 76% more likely to die in the hospital.
  • All studies defined vitamin D deficiency differently, but stratifying participants based on specific vitamin D levels yielded similar results.

The researchers concluded,

“This study showed that vitamin D deficiency is associated with an increased hospital mortality in critically ill adult patients. However, there is not enough evidence to conclude that vitamin D deficiency is associated with increased ICU mortality in critically ill adult patients, which need more studies to probe further into it in the future.”

They went on to add,

“Vitamin D levels may not only predict disease severity and outcomes but also contribute to the co-morbidities commonly seen in critically illness.”

They pointed out that some studies were conducted in specific ICUs, such as a surgical ICU, which limits the study’s generalizability to all hospital patients. Also, the cohorts defined vitamin D deficiency differently which could affect the study’s primary findings.

It is unlikely that clinical trials comparing vitamin D to a placebo group of critically ill patients will ever be conducted due to ethical objections. Future studies should find the safest and most effective dose of vitamin D for critically ill patients.


Zhang Y. et al. Association between vitamin D deficiency and mortality in critically ill adult patients: a meta-analysis of cohort studies. Critical care, 2014.

  About: Amber Tovey

Amber is the Program Manager for the Vitamin D Council. Her responsibilities include writing articles, editing, fundraising and brainstorming ways for the VDC to grow. Outside of work, she loves to enjoy the beautiful hills, beaches and sunshine in the Central Coast of California.