The association between hypertensive disorders of pregnancy and childhood asthma.

ABSTRACT

BACKGROUND: Asthma is a chronic long-term inflammatory disease of the airways and is a major global health challenge. The primary aim of this study was to investigate the association between hypertensive disorders of pregnancy (HDP) and the risk of asthma at or before the age of seven years using the UK Millennium Cohort Study (MCS). METHODS: Overall, 18,552 families were recruited for wave one of the MCS when the child was 9 months old, and subsequently participated in waves two, three and four when they were three, five and seven years respectively. HDP were self-reported by mothers in wave one. The primary outcome was a parent-reported diagnosis of "ever asthma" at seven years, based on responses to a validated questionnaire. RESULTS: Following adjustment for a range of potential confounding factors, HDP was found to be associated with asthma in the offspring (adjusted odds ratio (AOR 1.35; 95% CI 1.15-1.59)). A larger effect estimate was observed amongst children exposed to HDP and born preterm (AOR 1.81; 95% CI 1.25-2.61) or small for gestational age (SGA) (AOR = 1.58; (95% CI 1.15-2.18)). CONCLUSIONS: In conclusion, children exposed to HDP may be at increased odds of asthma diagnosis by age seven, particularly if they were born preterm or SGA. IMPACT There is a paucity of data investigating the relationship between hypertensive disorders of pregnancy and childhood asthma, with recent studies showing conflicting results. Our study investigated this relationship using a large cohort with ample information on a wide range of confounding factors. Our study showed that individuals exposed to HDP may be at increased odds of asthma diagnosis by age seven years, particularly if they were also born SGA or preterm.