INTRODUCTION: Our aims are to asses the association of DDE with childhood asthma measured up to age six and the effect of DDE on the protective association of breastfeeding on asthma. In addition we pretend to asses the relevant time-window of exposure of DDE (i.e., at birth or at four years). RESULTS: At birth and at four years of age all children had detectable levels of DDE while for the DDT this occurred in 92% at birth and 60% at four years. The association between wheezing and DDE at birth varied by age, with a statistically significant interaction at ages three and four respect to ages 1 and 2. Only two children started wheezing after age four. Wheezing occurring at four (odds ratio = 1.13 (1.01–1.26) per each increase in 1 ng/ml) as well as asthma diagnosed at six (1.18 (1.01–1.3)) showed a statistically significant association with DDE measured at birth. The negative association of breastfeeding with wheezing at any age and asthma at six was not modified by levels of DDE (p for interaction > 0.6). DDE at four and DDT did not show any association.
METHODS: All women presenting for antenatal care in Menorca (Spain) over 12 months starting in mid 1997 were invited to take part in a longitudinal study. 482 children were subsequently enrolled and 462 provided complete outcome data up to the six year and a half of study. Organochlorine compounds were measured in cord serum in 402 (83%) children and in 285 at age four. Asthma was defined based on wheezing at any age or doctor diagnosed asthma at age six and a half. Prick test at age six was used to measure atopy.
CONCLUSIONS: Early exposures to DDE seem to play a role in asthma, but not exposures occurring during breastfeeding or later.
