Researchers using NHANES data have found that those with vitamin D deficiency are more likely to have (or have had) community-acquired pneumonia.
Community-acquired pneumonia (CAP) is the most common type of pneumonia. It is condition where the lungs become inflamed, specifically the alveoli of the lung. You acquire CAP outside the hospital setting usually by virus or bacterial infection.
CAP is prevalent today with an estimated 4 to 5 million new cases per year in the United States. Direct and indirect health costs of CAP are greater than $17 billion annually.
Research has shown that vitamin D is associated with a variety of respiratory functions. More recently, researchers have taken a close look if there’s a link between vitamin D and pneumonia. A past study showed that vitamin D deficient individuals are 2.5 times more likely to develop pneumonia, while on the other hand, a study showed that prescribing vitamin D had no effect on pneumonia (this latter study was not a controlled trial).
These studies have led researchers to look for more conclusive answers. It is clear that vitamin D plays some role in pneumonia, but the question still remains as to how.
Recently, Dr. Sadeq Quraishi of Harvard University and colleagues set out to look at the relationship between the two, by examining one of the largest health cohorts, the Third National Health and Nutrition Examination Survey (NHANES III). Dr. Quraishi is on the board at the Vitamin D Council and has been a figurehead in vitamin D and health research.
By using NHANES data, Dr. Quraishi and his team were able to look at 16,975 Americans all with reported 25(OH)D levels. They wanted to know, prior to the vitamin D level being drawn, which participants had CAP the 12 months prior? Is there a correlation between vitamin D levels and risk of getting pneumonia?
Here is what they found:
- The median serum 25(OH)D level was 24 ng/ml.
- 2.1% of the whole cohort had CAP within 12 months.
- Individuals with vitamin D levels less than 30 ng/ml had a 56% greater risk of having CAP compared with those at or greater than 30 ng/ml (OR 1.56, P <0.001).
- When segmenting the group who had less than 30 ng/ml, those with less than 10 ng/ml had higher risk of having CAP (OR 2.25) than those at 10 – 19.9 ng/ml (OR 1.26, P <0.001) and 20 – 29.9 ng/ml (OR 1.70, P <0.001).
- Overall, 3.12% of the group at less than 10 ng/ml reported cases of CAP compared with 1.36% of the group at or greater than 30 ng/ml.
Dr. Quraishi and his team noted that there are limitations in their study. They pointed out that because of the nature of the data (observational), low vitamin D status may be a reflection of poor health and not directly related to CAP. Additionally, the researchers weren’t able to control for the time between cases of CAP and timing of blood draws. Because of this they cannot rule out reverse causation.
The researchers concluded,
“We demonstrated that 25(OH)D levels <30 ng/ml were indeed associated with a significant increase in the odds of CAP in the general population. While others have also hypothesized that vitamin D status may play an important protective role against various pulmonary diseases, our work provides important evidence to suggest that vitamin D supplementation may offer a novel approach to lowering the risk of CAP.”
Future studies that use vitamin D supplementation as an intervention in the prevention or treatment of pneumonia should elucidate the relationship between pneumonia and vitamin D.