Low Vitamin D levels linked to upper respiratory tract infections

Research about the values of Vitamin D has been in the news a lot lately. A new study reinforces its value. According to this study, the lower the levels of serum 25(OH)D levels the higher the prevalence of flu and colds in the patients studied.

"The findings of our study support an important role for vitamin D in prevention of common respiratory infections, such as colds and the flu," says Adit Ginde, MD, MPH, UC Denver Division of Emergency Medicine and lead author of the study in a recent news release. "Individuals with common lung diseases, such as asthma or emphysema, may be particularly susceptible to respiratory infections from vitamin D deficiency."

Information from approximately 19,000 subjects who participated in the Third National Health and Nutrition Examination Survey (NHANES III) was analyzed for this study.

Compared with individuals with serum 25(OH)D levels of 30 ng/mL or more, those with levels less than 10 ng/mL or 10 to less than 30 ng/mL had 55% and 27% higher odds of recent URTI, respectively (Table 2, model 1). In further stratification of the group with 25(OH)D levels of 30 ng/mL or more, those with levels of 30 to less than 40 ng/mL had similar odds of recent URTI compared with those with levels of 40 ng/mL or more (OR, 0.99; 95% CI, 0.81-1.21). After adjusting for season, lower serum 25(OH)D levels were still associated with a significantly higher URTI (Table 2, model 2). Indeed, the 25(OH)D-URTI association was consistent across all seasons.

"A respiratory infection in someone with otherwise healthy lungs usually causes a few days of relatively mild symptoms," explains Carlos Camargo, MD, DrPH, MGH Department of Emergency Medicine and senior author of the study. "But respiratory infections in individuals with an underlying lung disease can cause serious attacks of asthma or COPD that may require urgent office visits, emergency department visits or hospitalizations. So the impact of preventing infections in these patients could be very large."

The authors stress that the study's results need to be confirmed in clinical trials before vitamin D can be recommended to prevent colds and flu.

...randomized controlled trials are valuable for determining the causal nature of an observed association. Reverse causation (ie, lower serum 25[OH]D levels due to recent URTI and, thus, decreased outdoor activity) seems unlikely because the half-life of serum 25(OH)D is 2 to 3 weeks11 and URTIs last only 3 to 4 days,3 but it may affect the enhanced vitamin D–URTI association in participants with asthma and COPD owing to longer symptom duration in those individuals....Randomized controlled trials are warranted to explore the direct effect of vitamin D supplementation and to establish optimal levels of serum 25(OH)D in the prevention of RTI.

Previous articles about which I've blogged, Vitamin D and the thyroid gland... and Vitamin D: "Normal" isn't normal anymore support greater daily intake of Vitamin D.


To read more:

• Assay Variation Confounds the Diagnosis of Hypovitaminosis D: A Call for Standardization
• Assessment of dietary vitamin D requirements during pregnancy and lactation
• Circulating Vitamin D3 and 25-hydroxyvitamin D in Humans: An Important Tool to Define

Adit A. Ginde, MD, MPH; Jonathan M. Mansbach, MD; Carlos A. Camargo Jr, MD, DrPH (2009). Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey Archives of Internal Medicine, 169(4)

Fast forward...

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I meant to get back here before now to add more information. Right now, all I can do is try to not get sick from the sinus infection that is pulling me down. Yep, went to the doctor, got the antibiotic, and you'd think it would be simple as that. Not.

Since the removal of my pituitary adenoma involved transsphenoidal endoscopic surgery which went through said sinuses to the base of my brain, it is a tad worrisome. Not mention the fact that any stress on the body (good, bad, or indifferent) causes some degree of adrenal insufficiency (AI). This includes infections. In fact, it often is the first indication I have of any infection.

Back to the doctor. My doctor. She is a sweet person. In fact, she was the only one in all these years of suffering with Cushing's Disease who realized I had something "endocrine" going on until I saw Dr. Friedman in Los Angeles. However, that's about as far as she went with the understanding of the disease. Since she is willing to listen and work with me, I don't hold it against her. I do hold it against medical schools who don't teach their doctors enough about this disease. She doesn't understand AI. She doesn't understand what the tumor did or how it messed up my system even beyond removal. She doesn't get "stress dosing" to combat the AI. But she does understand a sinus infection. Just not how bad it can be. At least she now asks "what works" and then prescribes it. And she cares. There's a lot to be said for that. A whole lot.

I wish I could get rid of the headache. It won't go away.