Onset and remission of eczema at pre-school age in relation to prenatal and postnatal air pollution and home environment across China

Chan Lu,Dan Norbäck,Yinping Zhang,Baizhan Li,Zhuohui Zhao,Chen Huang,Xin Zhang,Hua Qian,Yuexia Sun,Jan Sundell,Juan Wang,Wei Liu,Qihong Deng

doi:10.1016/j.scitotenv.2020.142467

Abstract

We investigated associations between prenatal and postnatal environmental factors and onset and remission of preschool childhood eczema across China. The study population was preschoolers in randomized day care centers in seven cities (N = 39,782). Data on eczema and prenatal and postnatal indoor and outdoor environment were obtained from a cross-sectional questionnaire sent to parents or other guardians. Reports on eczema in the first 2 years and in the past year was used to retrospectively calculate onset and remission (changes of reported eczema). Prenatal and postnatal outdoor temperature, NO2 and PM10 were modelled from official air pollution data. Associations were estimated by two-level logistic regression. Calculated onset rate was 3.2%/y and remission rate 29.2%/y. Exposure to NO2 during pregnancy was associated with onset of eczema, similarly for all trimesters. Postnatal PM10 and NO2 were related to decreased remission. Postnatal outdoor temperature was associated with onset of eczema. Pre-natal and current redecoration or buying new furniture, and perinatal as well as current dampness and indoor mould, were associated with increased onset and decreased remission. Cockroaches in current home was another indoor risk factors. Prenatal exposure to farm environment and large family size were all negatively associated with eczema. In conclusion, a warmer climate and prenatal NO2 can be associated with increased onset of eczema in Chinese preschoolers. Postnatal PM10 and NO2 can be associated with reduced remission. Perinatal and current dampness, indoor mould and cockroaches may increase onset and decrease remission. Exposure to chemical emissions from indoor materials after first year of life may increase onset. Prenatal exposure to farm environment and large family size could be protective.

Highlights

Eczema or atopic dermatitis is a common childhood skin disorder
We found that the remission rate of eczema was higher than the onset rate, indicating a potential for preventing the eczema to continue up to school age
We found that prenatal PM10 exposure in the third trimester was negatively associated with onset of eczema

Summary

Introduction

Eczema or atopic dermatitis is a common childhood skin disorder. In some areas, over 20% of the children can have eczema (Odhiambo et al, 2009). Prospective studies have demonstrated that eczema in pre-school age can be a predictor of later development of asthma and allergic rhinitis (von Kobyletzki et al, 2012; Bröms et al, 2012), suggesting that early identification of environmental risk factors and protective factors for childhood eczema is important. There is a considerable remission of eczema at pre-school age and this remission can be more pronounced in less urbanized areas (von Kobyletzki et al, 2014). It is important to investigate how exposure in different parts of early life can influence the development of childhood eczema

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Discussion

Conclusion