title: [Inverse association between asthma and neural tube defects: a binational ecological study].
abstract: OBJECTIVE
  Dietary intake of methyl donors such as folic acid prevents neural tube defects (NTD), but recent studies showed that it might also favor the development of asthma. In this work a possible ecological association between NTD and asthma was explored.
  
  
  METHODS
  Data bases from Mexico and the United States (US) were reviewed to obtain information about geographical distribution (by state) and temporal trends (by year) of NTD and asthma.
  
  
  RESULTS
  Those states with the lowest frequency of NTD had the highest frequency of asthma, both in Mexico (rS=-0.48, p=0.005) and US (rS=-0.39, p=0.005). Temporal trends also showed an inverse correlation in Mexico (1997-2007, rS=-0.73, p=0.01) and US (1979-1998, rS=-0.91, p<0.001).
  
  
  CONCLUSIONS
  In both countries the frequency of asthma inversely correlated with the frequency of NTD, both in geographical distribution and annual trends, giving support to the possibility that methyl donors intake in diet or supplements is influencing the asthma frequency.
authors: Departamento de Investigación en Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias, 14080, México DF, México. mhvargasb@yahoo.com.mx
authors: Mario H
authors: MH
authors: Vargas
authors: Patricia
authors: P
authors: Campos-Bedolla
authors: Patricia
authors: P
authors: Segura
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000757:Anencephaly / Q000453:epidemiology / Q000517:prevention & control; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D062306:Geography, Medical; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009436:Neural Tube Defects / Q000453:epidemiology* / Q000517:prevention & control; D011247:Pregnancy; D016135:Spinal Dysraphism / Q000453:epidemiology / Q000517:prevention & control; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D005492:Folic Acid