Early childhood wheezing symptoms in relation to plasma selenium in pregnant mothers and neonates.

OBJECTIVE: Reduced dietary selenium intake has been linked to the development of asthma. We have investigated whether childhood wheezing symptoms, and asthma up to the age of 5 years are associated with plasma selenium and erythrocyte glutathione peroxidase (GPx) concentrations in pregnant mothers and neonates.
METHODS: Two thousand pregnant women were recruited and their 1924 singleton children followed up. Plasma selenium and erythrocyte GPx concentrations were measured in maternal blood during early pregnancy (12 weeks gestation) and in neonatal cord blood. Cohort children were followed up at 1, 2 and 5 years using a respiratory symptom questionnaire and at 5 years children were also invited for spirometry and skin-prick test (SPT). Maternal and neonatal plasma selenium and erythrocyte GPx were related to the childhood outcomes of wheezing, and asthma.
RESULTS: At 2 years 1282 children were followed up. At 5 years symptom data were available for 1167 children, 700 children were SPT tested, and forced expiratory volume in 1 s (FEV(1)) was measured in 478. Maternal plasma selenium concentration during early pregnancy was inversely associated with wheezing (odds ratio per 10 microg/kg plasma selenium 0.86, 95% confidence interval 0.76-0.97), and consulting a doctor because of wheeze (0.79, 0.69-0.93) in the second year of life. Cord plasma selenium was also inversely associated with wheezing (0.67, 0.47-0.96), and consulting a doctor because of wheeze (0.62, 0.41-0.93) in the second year of life. By age 5 these associations had disappeared. Maternal and neonatal erythrocyte GPx concentrations were not associated with any childhood outcomes at 2 or 5 years.
CONCLUSION: The selenium status of mothers during early pregnancy, and neonates is associated with early childhood wheezing but not asthma or atopic sensitization, furthermore, this association is absent by the age of 5 years.