Serum vitamin D levels and markers of severity of childhood asthma in Costa Rica.
BACKGROUND
Maternal vitamin D intake during pregnancy has been inversely associated with asthma symptoms in early childhood. However, no study has examined the relationship between measured vitamin D levels and markers of asthma severity in childhood.


OBJECTIVE
To determine the relationship between measured vitamin D levels and both markers of asthma severity and allergy in childhood.


METHODS
We examined the relation between 25-hydroxyvitamin D levels (the major circulating form of vitamin D) and markers of allergy and asthma severity in a cross-sectional study of 616 Costa Rican children between the ages of 6 and 14 years. Linear, logistic, and negative binomial regressions were used for the univariate and multivariate analyses.


RESULTS
Of the 616 children with asthma, 175 (28%) had insufficient levels of vitamin D (<30 ng/ml). In multivariate linear regression models, vitamin D levels were significantly and inversely associated with total IgE and eosinophil count. In multivariate logistic regression models, a log(10) unit increase in vitamin D levels was associated with reduced odds of any hospitalization in the previous year (odds ratio [OR], 0.05; 95% confidence interval [CI], 0.004-0.71; P = 0.03), any use of antiinflammatory medications in the previous year (OR, 0.18; 95% CI, 0.05-0.67; P = 0.01), and increased airway responsiveness (a < or =8.58-mumol provocative dose of methacholine producing a 20% fall in baseline FEV(1) [OR, 0.15; 95% CI, 0.024-0.97; P = 0.05]).


CONCLUSIONS
Our results suggest that vitamin D insufficiency is relatively frequent in an equatorial population of children with asthma. In these children, lower vitamin D levels are associated with increased markers of allergy and asthma severity.
Brehm
John M
JM
Channing Laboratory, 181 Longwood Avenue, Boston, MA 02115, USA.
Celedón
Juan C
JC
Soto-Quiros
Manuel E
ME
Avila
Lydiana
L
Hunninghake
Gary M
GM
Forno
Erick
E
Laskey
Daniel
D
Sylvia
Jody S
JS
Hollis
Bruce W
BW
Weiss
Scott T
ST
Litonjua
Augusto A
AA
D000293:Adolescent; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001249:Asthma / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D002648:Child; D003364:Costa Rica; D004804:Eosinophils / Q000378:metabolism; D005260:Female; D005541:Forced Expiratory Volume; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D006967:Hypersensitivity / Q000097:blood; D007073:Immunoglobulin E / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D016210:Methacholine Chloride; D015999:Multivariate Analysis; D012720:Severity of Illness Index; D013147:Spirometry; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D014807:Vitamin D; D007073:Immunoglobulin E; C104450:25-hydroxyvitamin D