Effect of Early Life Geohelminth Infections on the Development of Wheezing at 5 Years of Age.

RATIONALE: Exposures to geohelminths during gestation or early childhood may reduce risk of wheezing illness/asthma and atopy during childhood in tropical regions. OBJECTIVES: To investigate the effect of maternal and early childhood geohelminths on development of wheeze/asthma and atopy during the first 5 years of life. METHODS: Cohort of 2,404 neonates followed to 5 years of age in rural District in coastal Ecuador. Data on wheeze collected by questionnaire and atopy measured by allergen skin prick test reactivity to 9 allergens at 5 years. Stool samples from mothers and children examined for geohelminths by microscopy. MEASUREMENTS AND MAIN RESULTS: 2,090 (86.9%) children were evaluated at 5 years. Geohelminths were observed in 45.5% of mothers and in 34.1% of children by 3 years. Wheeze and asthma were reported for 12.6% and 5.7% of children, respectively, while 14.0% had skin test reactivity at 5 years. Maternal geohelminths were associated with an increased risk of wheeze (adjusted OR 1.41, 95% CI 1.06-1.88) while childhood geohelminths over the first 3 years of life were associated with reduced risk of wheeze (adjusted OR 0.70, 95% CI 0.52-0.96) and asthma (adjusted OR 0.60, 95% CI 0.38-0.94) but not skin prick test reactivity. The effects on wheeze/asthma were greatest with later age of first infection, were observed only in skin test-negative children but were not associated with parasite burden or specific geohelminths. CONCLUSIONS: While maternal exposures to geohelminths may increase childhood wheeze, childhood geohelminths during the first 3 years may provide protection through a non-allergic mechanism