TABLE 4.

SERUM VITAMIN D AND NUMBER OF HOSPITALIZATIONS AMONG COSTA RICAN CHILDREN WITH ASTHMA IN THE PREVIOUS YEAR

	Beta Coefficient (95% CI) (P Value)
Outcome	Unadjusted	Multivariate Model*
Vitamin D deficiency (<20 ng/ml)	1.9 (0.2 to 3.7) (0.03)	2.3 (0.65 to 4.0) (0.006)†
Age, years		−0.02 (−0.25 to 0.21) (0.9)
Female sex		0.19 (−0.68 to 1.1) (0.7)
BMI z-score		0.1 (−0.30 to 0.51) (0.6)
log10 dose–response slope for methacholine		0.76 (−0.16 to 1.7) (0.1)
Parental education		−0.06 (−0.43 to 0.3) (0.7)
Positive IgE to cockroach		1.1 (0.27 to 2.0) (0.01)
Antiinflammatory medication use		0.83 (−0.03 to 1.7) (0.06)

Boldface entries indicate significance.

^*The multivariate model is the final model after stepwise removal of covariates. Age, sex, and BMI z-score were forced into the model. Other variables also remained in the final models if they were significant at P < 0.05 or if they satisfied a change in estimate criterion (≥10%) in the beta coefficient. Variables removed include maternal asthma history, paternal asthma history, positive IgE to Ascaris, and positive IgE to dust mite.

^†In the multivariate model, a vitamin D level less than 20 ng/ml predicts a 10-fold increase in hospitalizations over a 1-year period.