Pre-eclampsia and risk of early-childhood asthma: a register study with sibling comparison and an exploration of intermediate variables. (18th October 2021)

• Record Type: Journal Article
• Authors: Byberg, Kristine Kjer; Lundholm, Cecilia; Brew, Bronwyn K; Rejnö, Gustaf; Almqvist, Catarina
• Is Part Of: International journal of epidemiology. Volume 51:Number 3(2022)
• Page Start: 749
• Page End: 758
• Publication Date: 2021-10-18
• Subjects: Asthma -- caesarean section -- child -- epidemiology -- intermediate -- pre-eclampsia -- prematurity -- registers -- sibling -- small for gestational age; Epidemiology -- Periodicals; 614.4
• DOI: 10.1093/ije/dyab204
• Languages: English
• ISSNs: 0300-5771

Abstract

Abstract: Background: We aimed to study whether pre-eclampsia is associated with childhood asthma, allergic and non-allergic asthma, accounting for family factors and intermediate variables. Methods: The study population comprised 779 711 children born in 2005–2012, identified from Swedish national health registers ( n = 14 823/7410 exposed to mild/moderate and severe pre-eclampsia, respectively). We used Cox regression to estimate the associations of mild/moderate and severe pre-eclampsia with incident asthma, before and after age 2 years. Cox regressions were controlled for familial factors using sibling comparisons, then stratified on high and low risk for intermediate variables: caesarean section, prematurity and small for gestational age. We used logistic regression for allergic and non-allergic prevalent asthma at 6 years as a measure of more established asthma. Results: The incidence of asthma in children was 7.7% ( n = 60 239). The associations varied from adjusted hazard ratio (adjHR) 1.11, 95% confidence interval (CI): 1.00, 1.24 for mild/moderate pre-eclampsia and asthma at >2 years age, to adjHR 1.78, 95% CI: 1.64, 1.95 for severe pre-eclampsia and asthma at <2 years age. Sibling comparisons attenuated most estimates except for the association between severe pre-eclampsia and asthma at <2 years age (adjHR 1.45, 95% CI: 1.10, 1.90), which also remained when stratifying for the risk of intermediates. Mild/moderate and severe pre-eclampsia were associated with prevalent non-allergic (but not allergic) asthma at 6 years, with adjusted odds ratio (adjOR) 1.17, 95% CI: 1.00, 1.36 and adjOR 1.51, 95% CI: 1.23, 1.84, respectively. Conclusions: We found evidence that severe, but not mild/moderate, pre-eclampsia is associated with asthma regardless of familial factors and confounders.