Early-life exposures to geohelminths may protect against the development of wheeze/asthma and atopy. Objective: Study effect of maternal geohelminths and infections in children during the first 5 years of life on atopy, wheeze/asthma, and airways reactivity/inflammation at 8 years. Methods: Birth cohort of 2,404 neonates followed to 8 years in rural Ecuador. Data on wheeze/asthma were collected by questionnaire and atopy by skin prick test (SPT) reactivity to 9 allergens. We measured airways

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... ctivity to bronchodilator, fractional exhaled nitric oxide (FeNO), and nasal eosinophilia. Stool samples were examined for geohelminths by microscopy. Results: 1,933 (80.4%) children were evaluated at 8 years. Geohelminths were detected in 45.8% of mothers and in 45.5% of children to 5 years. Frequencies of outcomes at 8 years were: wheeze (6.6%), asthma between 5 and 8 years (7.9%), SPT (14.7%), airways reactivity (10%), and elevated FeNO (10.3%) and nasal eosinophilia (9.2%). Any maternal geohelminth was associated with reduced prevalence of SPT (OR 0.72). Childhood T. trichiura infections were associated with reduced wheeze (OR 0.57) but greater parasite burdens with A. lumbricoides were associated with increased wheeze (OR 2.83) and asthma (OR 2.60). Associations between maternal geohelminths and wheeze/asthma were modified by atopy. Parasite-specific effects on wheeze/asthma and airways reactivity and inflammation were observed in non-atopic children. Conclusions: Our data provide novel evidence for persistent effects of in utero geohelminth exposures on childhood atopy but highlight the complex nature of the relationship between geohelminths and the airways. Registered as an observational study (ISRCTN41239086).