Sixty-one PICU patients and 46 control patients were enrolled. Over 60% of the PICU cases were
found to be vitamin D insufficient while less than 1/3 of the controls were insufficient (p < 0.0001)
No significant correlation was seen between plasma 25(OH)D and any severity of illness scores. Cases with asthma had a significantly lower median level 25(OH)D (16.9 ng/mL) than cases without asthma (18.7 ng/mL). Over 50% of patients hospitalized during the fall and winter were considered vitamin D deficient or insufficient whereas in the sunnier seasons (spring and summer) the prevalence of vitamin D deficiency/insufficiency decreased to about 30% (p ¼ 0.003).