Raising vitamin D levels may help control flare-ups in people with asthma.
Israeli researchers studied 308,000 people whose vitamin D blood levels had been recorded. They found no association of low vitamin D with an initial diagnosis of asthma. But inadequate levels were significantly associated with the number and severity of attacks in the 21,237 people in the group who had had asthma diagnosed.
Even after controlling for sex, age, ethnicity, smoking and other factors, the researchers found that the lower the vitamin D level, the greater the incidence of recurrent asthma attacks.
Worsening of asthma was indicated by the number of prescriptions for asthma medicine filled and the number of physician visits. The researchers found that during the year before their first vitamin D test, 15 percent of people with readings between 0 and 10 nanograms per milliliter had at least one flare-up. But only 12 percent of those with readings of 10 to 20 and 9 percent of those with readings above 36, a level generally considered adequate, did. The study appeared in the journal Allergy.
“I think that if a patient has had good treatment for asthma and is still not controlled, maybe he should be checked for his vitamin D levels before adding on more medications,” said the lead author, Dr. Ronit Confino-Cohen, a senior lecturer at Meir Medical Center in Kfar Saba, Israel. “Maybe supplementation would do the job.”