Impaired fetal growth decreases the risk of childhood atopic eczema: a Swedish twin study
Article first published online: 23 APR 2010
© 2010 Blackwell Publishing Ltd
Clinical & Experimental Allergy
Volume 40, Issue 7, pages 1044–1053, July 2010
How to Cite
Lundholm, C., Örtqvist, A. K., Lichtenstein, P., Cnattingius, S. and Almqvist, C. (2010), Impaired fetal growth decreases the risk of childhood atopic eczema: a Swedish twin study. Clinical & Experimental Allergy, 40: 1044–1053. doi: 10.1111/j.1365-2222.2010.03519.x
- Issue published online: 10 JUN 2010
- Article first published online: 23 APR 2010
- Submitted 27 December 2009; revised 15 March 2010; accepted 19 March 2010
- allergic rhinitis;
- atopic dermatitis;
- birth weight;
- gestational age;
- twin study
Background Studies have found associations between birth weight and risk of atopic eczema or allergic rhinitis (AR), although this could be due to confounding.
Objective We sought to evaluate associations between fetal growth and the risk of atopic eczema or AR in childhood, controlling for gestational age (GA), shared (familial) environmental and genetic factors.
Methods Data on atopic eczema, AR, birth characteristics and confounders were collected from registers and telephone interviews with the parents of 9- and 12-year-old twins. Firstly, cohort analyses on all twins (eczema n=10 132 and AR n=10 896) were performed. Secondly, to control for genetic and shared environment, co-twin-control analyses were performed in twin pairs discordant for atopic eczema (n=480) and AR (n=332).
Results The rate of atopic eczema increased with birth weight, from 12.6% in twin children <2000 g to 17.3% in children 3500 g. The rate of AR varied between 7.8% and 8.8%. In the cohort analyses, the odds ratio (OR) for atopic eczema was 1.62 (95% CI: 1.27–2.06) for 500 g increase in birth weight and 1.00 (95% CI: 0.75–1.33) for AR. In co-twin-control analyses on atopic eczema, OR was 3.93 (95% CI: 1.55–9.98) for 500 g increase in birth weight, with no significant difference between monozygotic and dizygotic twins (P=0.84).
Conclusions We found a positive association between fetal growth and childhood atopic eczema, but not AR, independent of GA, shared environmental and genetic factors. This indicates fetal growth affects the immune system, and supports further studies on early mechanisms.
Cite this as: C. Lundholm, A. K. Örtqvist, P. Lichtenstein, S. Cnattingius and C. Almqvist, Clinical & Experimental Allergy, 2010 (40) 1044–1053.