Pre-eclampsia and childhood asthma.
Studies of pre-eclampsia and childhood asthma are conflicting, and none have performed a formal mediation analysis of preterm birth.We examined the association between pre-eclampsia and asthma at 7 years using national registries, including all births in Norway from 1999 to 2006 (n=406 907), and a subsample of children in the Norwegian Mother and Child Cohort Study (MoBa) (n=45 028) using log-linear regression. We performed a mediation analysis of preterm birth, and a sibling comparison to evaluate unobserved confounding.There was a positive association between pre-eclampsia and asthma in the registry study, with an adjusted relative risk of 1.31 (95% CI 1.22-1.41), but not in MoBa, which had an adjusted relative risk of 1.19 (95% CI 0.99-1.44). The odds ratios for the direct effect not mediated through preterm birth and the indirect effect in the registry linkage were 1.19 (95% CI 1.10-1.29) and 1.12 (95% CI 1.11-1.14), respectively. The sibling comparison indicated no association between pre-eclampsia and asthma (adjusted OR 1.07, 95% CI 0.87-1.33).In this large study, which used different datasets and analytic approaches, there was little evidence for an association between pre-eclampsia and childhood asthma. The association was weak and largely explained by pre-term birth and confounders shared by siblings.
Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway Maria.Christine.Magnus@fhi.no.|MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.|School of Social and Community Medicine, University of Bristol, Bristol, UK.
Maria C
MC
Magnus
Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway.
Siri E
SE
Håberg
Domain for Health Data and Digitalization, Norwegian Institute of Public Health, Oslo, Norway.
Per
P
Magnus
Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway.|Dept of Global Public Health and Primary Care, Medical Faculty, University of Bergen, Bergen, Norway.
Anders
A
Engeland
Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway.|Dept of Community Medicine, Medical Faculty, University of Oslo, Oslo, Norway.
Per
P
Nafstad
Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway.
Øystein
Ø
Karlstad
Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway.
Wenche
W
Nystad
D000328:Adult; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D047928:Premature Birth / Q000453:epidemiology*; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D035781:Siblings; D055815:Young Adult