Objective: To evaluate the association of late-preterm birth with asthma severity among young children.
Methods: A retrospective cohort study was performed with electronic health record data from 31 practices affiliated with an academic medical center. Participants included children born in 2007 at 34 to 42 weeks of gestation and monitored from birth to 18 months. We used multivariate logistic or Poisson models to assess the impact of late-preterm (34-36 weeks) and low-normal (37-38 weeks) compared with term (39-42 weeks) gestation on diagnoses of asthma and persistent asthma, inhaled corticosteroid use, and numbers of acute respiratory visits.
Results: Our population included 7925 infants (7% late-preterm and 21% low-normal gestation). Overall, 8.3% had been diagnosed with asthma by 18 months. Compared with term gestation, late-preterm gestation was associated with significant increases in persistent asthma diagnoses (adjusted odds ratio [aOR]: 1.68), inhaled corticosteroid use (aOR: 1.66), and numbers of acute respiratory visits (incidence rate ratio: 1.44). Low-normal gestation was associated with increases in asthma diagnoses (aOR: 1.34) and inhaled corticosteroid use (aOR: 1.39).
Conclusion: Birth at late-preterm and low-normal gestational ages might be an important risk factor for the development of asthma and for increased health service use in early childhood.