Impact of early life geohelminths on wheeze, asthma, and atopy in
Ecuadorian children at 8 years.
Background: 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 reactivity 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).