Abstract
Background : The incidence of eczema is higher in children aged
0-2 years, but the long-term effect of air pollutants exposure in early
life on the risk of eczema development is unclear.
Methods : We conducted a birth cohort study in Jinan, China, to
explore the effect of early life air pollutant exposure on the risk of
eczema in younger children. An inverse distance weighting method was
used for individual exposure assessment. Binary and multivariate
logistic models were used to investigate the effects of air pollutants
on eczema, the distributed lag model to find sensitive windows of
exposure, weighted quantile sum model and principal component analysis
to explore the combined effects of multiple pollutants.
Results : The cumulative incidence rate for eczema among 5819
children aged 2 was 19.8%. Exposure to high levels of
O3 during pregnancy (OR 1.12, 95%CI1.06-1.19) and during the first year after birth (OR 1.24,
95%CI 1.03-1.50) increased the risk of eczema.
PM2.5-10 during pregnancy (OR 1.31, 95%CI1.20-1.43), PM2.5 (OR 1.08, 95%CI1.01-1.15) and PM2.5-10 (OR 1.07, 95%CI1.00-1.14) during the first year after birth also increased the risk of
eczema. The critical window for O3 and PM exposure was
the third trimester and early postnatal period. Moreover, in the
combined effect of multiple pollutants, O3 played a
dominant role during pregnancy (weighting > 0.3), with a
predominantly O3 principal component associated with
eczema risk (adjusted OR 1.011, 95% CI 1.007-1.015).
Conclusions : Exposure to air pollutants O3 and
PM in early life increased the risk of eczema at 0-2 years of age, and
the sensitivity window appeared earlier. O3 exposure
during pregnancy played a key role in the combined effect of pollutants
on eczema risk.
Keyword : Eczema, Air pollution, Cohort study, Early life, Joint
effect