The research looked only at patients with severe forms of COPD in a study that surprised researchers.
"Quitting smoking is the best way to avoid COPD."
Dr. Ken M. Kunisaki of the Minneapolis Veterans Affairs Medical Center noted that vitamin D insufficiency and deficiency are common among patients with severe forms of COPD, which led researchers to hypothesize that low vitamin D might increase the risk of sudden COPD symptoms. He said that the findings are in contrast to earlier studies that linked low vitamin D with higher levels of respiratory infections in adults and more frequent asthma attacks in children.
Researchers studied 973 patients with severe COPD during the randomized controlled trial. Of the patients, 33 percent were categorized as vitamin D insufficient and 32 percent were considered vitamin D deficient. The study was a secondary analysis of a study of the effects of common antibiotic azithromycin (Zithromax) on the frequency of sudden symptom worsening in COPD patients.
Patients were followed for a year with 37 percent of participants remaining free of sudden symptom worsening. Investigators defined an acute exacerbation as one of numerous complex respiratory symptoms including cough, wheezing, sputnum, dyspnea or chest tightness for at least three days. The symptoms, which could be new or recurring, also required an antibiotic.
No relationship was found between vitamin D and the sudden onset of COPD symptoms, or vitamin D and worsening COPD incidents.Participants with severe vitamin D deficiency had a higher mean rate of acute exacerbations of COPD, but the difference was not considered statistically significant.
Dr. Kunisaki concluded that vitamin D supplementation is unlikely to have an effect in lowering the risk of a sudden onset of COPD symptoms.
The study was published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.