title: Water hardness and eczema at 1 and 4 y of age in the INMA birth cohort.
abstract: BACKGROUND
  Exposure to hard water has been suggested as a risk factor for eczema in childhood, based on limited evidence from two ecologic and two cross-sectional studies.
  
  
  OBJECTIVE
  We evaluate this hypothesis for the first time in early infancy using prospective data from a mother-child cohort study.
  
  
  METHODS
  We used data from the INMA cohorts in Gipuzkoa, Sabadell and Valencia, Spain (N=1638). Current and ever eczema, bathing frequency and duration and covariables were collected by questionnaires at 14 months (14 m) and 4 years (4 y). Calcium carbonate (CaCO3) level in municipal water was assigned to home addresses at birth, 14 m and 4 y. We calculated Odds Ratio (OR) of eczema related to CaCO3 at home, bath exposure and a combination of both.
  
  
  RESULTS
  Prevalence of eczema ever was 18.4% at 14 m and 33.4% at 4 y. Mean CaCO3 ranged from 51.6 to 272.8 mg/L among areas. No association was detected between water hardness at home and current or ever eczema. Adjusted OR was 0.79 (95%CI=0.45, 1.39) at 14 m and 0.93 (0.56, 1.52) at 4 y among children in the highest vs. lowest tertiles of CaCO3. Bath exposure alone or in combination with water hardness did not increase the OR of eczema at 14 m or 4 y either.
  
  
  CONCLUSIONS
  We did not find an association between eczema and water hardness at home or bathing exposure during the first four years of life. This first cohort study in a critical age period with improved exposure assessment does not confirm the association suggested among children by previous studies.
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona Biomedical Research Park, 88 Doctor Aiguader, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), 80 Doctor Aiguader, Barcelona 08003, Spain; IMIM (Hospital del Mar Medical Research Institute), 88 Doctor Aiguader, Barcelona 08003, Spain; CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain. Electronic address: lfont@creal.cat.
authors: Laia
authors: L
authors: Font-Ribera
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona Biomedical Research Park, 88 Doctor Aiguader, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), 80 Doctor Aiguader, Barcelona 08003, Spain; IMIM (Hospital del Mar Medical Research Institute), 88 Doctor Aiguader, Barcelona 08003, Spain. Electronic address: egracia@creal.cat.
authors: Esther
authors: E
authors: Gracia-Lavedan
authors: CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain; FISABIO-UJI-Universitat de València Joint Research Unit, Av. Catalunya 21, Valencia 46020, Spain. Electronic address: esplugues_ana@gva.es.
authors: Ana
authors: A
authors: Esplugues
authors: CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain; FISABIO-UJI-Universitat de València Joint Research Unit, Av. Catalunya 21, Valencia 46020, Spain. Electronic address: ballester_fer@gva.es.
authors: Ferran
authors: F
authors: Ballester
authors: Public Health Division of Gipuzkoa, Basque Government, 4 Av. de Navarra, San Sebastian 20013, Spain; BIODONOSTIA Health Research Institute, Paseo Dr. Beguiristain, San Sebastian 20014, Spain. Electronic address: mambien1-san@euskadi.eus.
authors: Ana
authors: A
authors: Jiménez Zabala
authors: CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain; Public Health Division of Gipuzkoa, Basque Government, 4 Av. de Navarra, San Sebastian 20013, Spain; BIODONOSTIA Health Research Institute, Paseo Dr. Beguiristain, San Sebastian 20014, Spain. Electronic address: ambien4ss-san@ej-gv.es.
authors: Loreto
authors: L
authors: Santa Marina
authors: CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain; Universidad de Oviedo, Campus del Cristo, Oviedo, Spain. Electronic address: capua.uo@uniovi.es.
authors: Ana
authors: A
authors: Fernández-Somoano
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona Biomedical Research Park, 88 Doctor Aiguader, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), 80 Doctor Aiguader, Barcelona 08003, Spain; IMIM (Hospital del Mar Medical Research Institute), 88 Doctor Aiguader, Barcelona 08003, Spain; CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain. Electronic address: jsunyer@creal.cat.
authors: Jordi
authors: J
authors: Sunyer
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona Biomedical Research Park, 88 Doctor Aiguader, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), 80 Doctor Aiguader, Barcelona 08003, Spain; IMIM (Hospital del Mar Medical Research Institute), 88 Doctor Aiguader, Barcelona 08003, Spain; CIBER Epidemiologia y Salud Pública (CIBERESP), 3-5 Melchor Fernández Almagro, Madrid 28029, Spain. Electronic address: cvillanueva@creal.cat.
authors: Cristina M
authors: CM
authors: Villanueva
mesh_terms: D000328:Adult; D002675:Child, Preschool; D015331:Cohort Studies; D004485:Eczema / Q000209:etiology*; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012307:Risk Factors; D013030:Spain; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water
keywords: Atopic dermatitis; Bathing; Calcium carbonate; Early infancy