title: Folate Deficiency, Atopy, and Severe Asthma Exacerbations in Puerto Rican Children.
abstract: BACKGROUND
  Little is known about folate and atopy or severe asthma exacerbations. We examined whether folate deficiency is associated with number of positive skin tests to allergens or severe asthma exacerbations in a high-risk population and further assessed whether such association is explained or modified by vitamin D status.
  
  
  METHODS
  Cross-sectional study of 582 children aged 6 to 14 years with (n = 304) and without (n = 278) asthma in San Juan, Puerto Rico. Folate deficiency was defined as plasma folate less than or equal to 20 ng/ml. Our outcomes were the number of positive skin tests to allergens (range, 0-15) in all children and (in children with asthma) one or more severe exacerbations in the previous year. Logistic and negative binomial regression models were used for the multivariate analysis. All multivariate models were adjusted for age, sex, household income, residential proximity to a major road, and (for atopy) case/control status; those for severe exacerbations were also adjusted for use of inhaled corticosteroids and vitamin D insufficiency (a plasma 25[OH]D < 30 ng/ml).
  
  
  RESULTS
  In a multivariate analysis, folate deficiency was significantly associated with an increased degree of atopy and 2.2 times increased odds of at least one severe asthma exacerbation (95% confidence interval for odds ratio, 1.1-4.6). Compared with children who had normal levels of both folate and vitamin D, those with both folate deficiency and vitamin D insufficiency had nearly eightfold increased odds of one or more severe asthma exacerbation (95% confidence interval for adjusted odds ratio, 2.7-21.6).
  
  
  CONCLUSIONS
  Folate deficiency is associated with increased degree of atopy and severe asthma exacerbations in school-aged Puerto Ricans. Vitamin D insufficiency may further increase detrimental effects of folate deficiency on severe asthma exacerbations.
authors.affiliation: 1 Division of Pulmonary Medicine, Allergy, and Immunology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Joshua
authors.initials: J
authors.lastname: Blatter
authors.affiliation: 1 Division of Pulmonary Medicine, Allergy, and Immunology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: John M
authors.initials: JM
authors.lastname: Brehm
authors.affiliation: 2 Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors.forename: Joanne
authors.initials: J
authors.lastname: Sordillo
authors.affiliation: 1 Division of Pulmonary Medicine, Allergy, and Immunology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Erick
authors.initials: E
authors.lastname: Forno
authors.affiliation: 1 Division of Pulmonary Medicine, Allergy, and Immunology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Nadia
authors.initials: N
authors.lastname: Boutaoui
authors.affiliation: 3 Behavioral Sciences Research Institute and Department of Pediatrics, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Edna
authors.initials: E
authors.lastname: Acosta-Pérez
authors.affiliation: 3 Behavioral Sciences Research Institute and Department of Pediatrics, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: María
authors.initials: M
authors.lastname: Alvarez
authors.affiliation: 3 Behavioral Sciences Research Institute and Department of Pediatrics, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Angel
authors.initials: A
authors.lastname: Colón-Semidey
authors.affiliation: 2 Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors.forename: Scott T
authors.initials: ST
authors.lastname: Weiss
authors.affiliation: 2 Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors.forename: Augusto A
authors.initials: AA
authors.lastname: Litonjua
authors.affiliation: 3 Behavioral Sciences Research Institute and Department of Pediatrics, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Glorisa
authors.initials: G
authors.lastname: Canino
authors.affiliation: 1 Division of Pulmonary Medicine, Allergy, and Immunology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Celedón
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use; D002648:Child; D018450:Disease Progression; D005260:Female; D005492:Folic Acid / Q000097:blood; D005494:Folic Acid Deficiency / Q000453:epidemiology*; D005541:Forced Expiratory Volume; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D011647:Puerto Rico / Q000453:epidemiology; D012720:Severity of Illness Index; D012882:Skin Tests; D014797:Vital Capacity; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D000305:Adrenal Cortex Hormones; D001993:Bronchodilator Agents; D014807:Vitamin D; D005492:Folic Acid; C104450:25-hydroxyvitamin D
keywords: Puerto Ricans; asthma; children; folate