title: Early exposure to dichlorodiphenyldichloroethylene, breastfeeding and asthma at age six.
abstract: Our aims were to assess association of dichlorodiphenyldichloroethylene (DDE) with childhood asthma measured up to age 6 and the effect of DDE on the protective effect of breastfeeding on asthma. In addition, we attempted to assess the relevant time-window of DDE exposure (i.e. at birth or at 4 years). All women presenting for antenatal care in Menorca, Spain over a 12-month period beginning in mid-1997 were invited to take part in a longitudinal study that included a yearly visit. Four hundred eighty-two children were enrolled and 462 provided complete outcome data after 6.5 years of follow-up. Organochlorine compounds were measured in cord serum of 402 (83%) infants and in blood samples of 285 children aged 4. We defined asthma as the presence of wheezing at age 6 and during any preceding year or doctor-diagnosed asthma, and used skin prick test at age 6 to determine atopic status. Results At birth and 4 years of age, all children had detectable levels of DDE (median 1 ng/mL and 0.8 ng/mL, respectively). From birth to age 4, the mean DDE level among children with artificial feeding decreased by 72%, while among breastfed children it increased by 53%. Diagnosed asthma and persistent wheezing were associated with DDE at birth [odds ratio (OR) for an increase in 1 ng/mL, OR=1.18, 95% confidence interval (95% CI)=1.01-1.39 and OR=1.13, 95% CI=0.98-1.30, respectively], but not with DDE at 4 years. Neither breastfeeding nor atopy modified these associations (P>0.3). Breastfeeding protected against diagnosed asthma (OR=0.33, 95% CI=0.08-0.87) and wheezing (OR=0.53, 95% CI=0.34-0.82) in children with low and high DDE levels at birth. Conclusion In a community without known dichlorodiphenyltrichloroethane environmental releases, this study strengthens the evidence for an effect of DDE on asthma by measuring the disease at age 6 and does not support the hypothesis that DDE modifies the protective effect of breastfeeding on asthma.
authors.affiliation: Centre de Recerca en Epidemiologia Ambiental, Institut Municipal Investigació Mèdica, Catalonia, Spain. jsunyer@imim.es
authors.forename: J
authors.initials: J
authors.lastname: Sunyer
authors.forename: M
authors.initials: M
authors.lastname: Torrent
authors.forename: R
authors.initials: R
authors.lastname: Garcia-Esteban
authors.forename: N
authors.initials: N
authors.lastname: Ribas-Fitó
authors.forename: D
authors.initials: D
authors.lastname: Carrizo
authors.forename: I
authors.initials: I
authors.lastname: Romieu
authors.forename: J M
authors.initials: JM
authors.lastname: Antó
authors.forename: J O
authors.initials: JO
authors.lastname: Grimalt
mesh_terms: D001249:Asthma / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D003634:DDT / Q000009:adverse effects / Q000097:blood; D003633:Dichlorodiphenyl Dichloroethylene / Q000009:adverse effects* / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis; D007223:Infant; D007231:Infant, Newborn; D007306:Insecticides / Q000009:adverse effects* / Q000097:blood; D016015:Logistic Models; D008297:Male; D018811:Maternal Exposure; D011247:Pregnancy; D012135:Respiratory Sounds; D018570:Risk Assessment; D012882:Skin Tests
chemical_list: D007306:Insecticides; D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT