Middle Childhood Morbidity in Children Born Preterm: A Canadian Cohort Study.

Abstract

To assess the risk of middle-childhood (ages 5-10 years) morbidities among children born preterm. We conducted a population-based cohort study of children born in British Columbia, Canada (2004-2017), followed from ages 5 to 10 years. Gestational age was categorized as 22-28, 29-33, 34-36, 37-41 (reference), and 42-44 weeks. Morbidity outcomes were allergic, cardiac, dermatologic, endocrine, hematologic, renal, neurologic, oncologic, respiratory, rheumatologic, and sleep. Cox proportional hazard models were used to compute adjusted hazard ratios (aHRs) and 95% CIs. In the cohort of 510 424 children, 9.50% were born preterm. Morbidity rates ranged from <1.0% (eg, cardiac, gastrointestinal, epilepsy, and oncologic disorders) to 16.37% (allergic), with greater rates among children born preterm than at term. A dose-response relationship was observed for several outcomes, with risks increasing as gestational age decreased. For puberty and disorders of sexual development, aHRs (95% CIs) were 2.17 (1.51-3.11), 1.99 (1.67-2.37), and 1.28 (1.14-1.43) among children born at 22-28, 29-33, and 34-36 weeks, respectively. Corresponding aHRs (95% CIs) for cardiac conditions were 4.20 (2.87-6.14), 1.90 (1.47-2.45), and 1.51 (1.30-1.75); for neurologic conditions were 3.20 (2.96-3.46), 1.54 (1.47-1.61), and 1.27 (1.23-1.30); and for respiratory conditions were 2.55 (2.33-2.78), 1.52 (1.45-1.60), and 1.23 (1.19-1.26), respectively. Children born preterm show elevated morbidity risks at ages 5-10 years. Risks increased with decreasing gestational age, reinforcing the need for ongoing monitoring and interventions to reduce long-term health complications.