Kids with Asthma Benefit from Vitamin D
Vitamin D has been in the news a lot lately, and here is yet one more item to note, especially if you have kids with asthma: low levels of vitamin D are associated with poorer lung function and a greater need for asthma medication. But when asthmatic children take vitamin D, they may reduce their medication needs, according to a new study from National Jewish Health.
The Centers for Disease Control and Prevention report that 7 million children have asthma, which represents 9.4 percent of young people in the United States. Asthma rates in children younger than five increased more than 160 percent from 1980 to 1994, and the numbers continue to rise.
Daniel Searing, MD, and his fellow researchers at National Jewish Health evaluated the medical records of 100 children with asthma and reported that 47 percent of them had insufficient levels of vitamin D (less than 30 nanograms per milliliter of blood, ng/mL) and that 17 percent were vitamin D deficient (less than 20 ng/mL). They noted that these levels were similar to levels of vitamin D seen in the general population.
Poor vitamin D status in children and its health implications have been noted in previous studies, including two published in Pediatrics in summer 2009. Researchers from Albert Einstein School of Medicine and Johns Hopkins reported that 70 percent of children are not getting enough vitamin D, and these young people tend to have lower levels of good cholesterol, high blood sugar levels, metabolic syndrome, and higher blood pressure than their peers. Low levels of vitamin D may also increase children’s risk of developing heart disease later in life.
Another earlier study, published in the American Journal of Respiratory and Critical Care Medicine found that asthma symptoms may be worse for children who had low vitamin D levels. The study included 600 children from Costa Rica.
Searing and his colleagues noted that patients who had low vitamin D levels generally had higher levels of immunoglobulin E, an indicator of allergy, and responded positively to more allergens when tested for allergens such as dog and house dust mites. Asthmatic children with low vitamin D also had poorer lung function and a greater use of inhaled steroid, oral steroids, and long-acting beta agonists.
On the positive side, the researchers conducted some laboratory experiments using the corticosteroid dexamethasone, vitamin D, and cultured immune cells and found that vitamin D significantly increased the effectiveness of the drug. The combination of vitamin D and dexamethasone in one experiment improved the drug’s efficiency tenfold.
Senior author Donald Leung, MD, PhD, noted that “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.”
American Academy of Allergy, Asthma and Immunology
Brehm JM et al. American Journal of Respiratory and Critical Care Medicine 2009 May 1; 179(9) 765-71
Centers for Disease Control and Prevention
Kumar J et al. Pediatrics 2009 Aug 3
National Jewish Health
Reis JP et al. Pediatrics 2009 Aug 3