U. S. researchers have found that low levels of vitamin D have been linked to increased asthma symptoms and greater use of medication among children.

47 percent of their asthma patients have vitamin D levels considered insufficient, below 30 nano-grams per milliliter of blood, and 17 percent have deficient levels, below 20 ng/mL, researchers at the National Jewish Medical and Research Center in Denver say. Their findings are similar to the vitamin D levels found in the general population, the researchers further add.

It was also found by the paper that asthmatic children with low vitamin D levels have higher levels of IgE -- a marker of allergy. The researchers further say that these children are responding positively to more allergens in a skin prick test.

Study researcher Dr. Daniel Searing says in a statement, "Conversely, our findings suggest that vitamin D supplementation may help reverse steroid resistance in asthmatic children and reduce the effective dose of steroids needed for our patients."

Searing and colleagues examined electronic medical records of 100 pediatric asthma patients referred to National Jewish Health and tested vitamin D and corticosteroids interaction in laboratory experiments.

Senior author Dr. Donald Leung says, "Our work suggests that vitamin D enhances the anti-inflammatory function of corticosteroids. If future studies confirm these findings vitamin D may help asthma patients achieve better control of their respiratory symptoms with less medication." (With Inputs from Agencies)