Summertime may become even more youth-friendly with the recent discovery that the vitamin D produced from sun exposure plays a role in protecting against childhood asthma.

Researchers evaluated data from 45,000 schoolchildren in nine cities throughout Spain with varying climatic conditions. Youngsters living in colder, wetter cities with few hours of sunlight were shown to be at greater risk for developing asthma.

With an increase of 100 hours in mean annual sunny hours, the adjusted prevalence rate of asthma declined by 0.6% for 6- to 7-year-olds and by 1.1% for the 13- to 14-year-olds. Relative humidity was negatively associated with asthma for the teens.

“The results indicate that sunny hours have a protective effect on the prevalence of asthma in schoolchildren,” the investigators concluded.

A separate statement from the lead investigator noted, “Although we need more studies on this issue—this hypothesis is not even five years old — it is clear that an average level of sun exposure is important for the assimilation of vitamin D, a compound that is extremely important in preventing illnesses such as asthma, tuberculosis, and other infectious diseases.”

In related news, a study found that antibiotics are prescribed during nearly one in six U.S. pediatric ambulatory care visits for asthma when antibiotic need is undocumented. The authors call for additional education and interventions to prevent unnecessary antibiotic prescribing for asthma.

Arnedo-Pena A et al. Int J Biometeorol. 2011;55:423-434.

Paul IM et al. Pediatrics. 2011;127;1014-1021