Perinatal & Pediatric
Short and long-term mortality after preterm birth: Evidence from a national population-based cohort Asma M. Ahmed* Asma Ahmed Sonia M. Grandi Eleanor Pullenayegum Sarah D. McDonald Jason Pole Shahirose S. Premji Marc Beltempo Fabiana Bacchini prakesh S. Shah Petros Pechlivanoglou
Background: Preterm birth (PTB) is a leading cause of neonatal mortality. However, evidence on mortality beyond the neonatal period is limited, especially in North America. We aimed to examine the effect of PTB on mortality from 1 to 36 years of age.
Methods: Using administrative data from Statistics Canada, we created a population-based cohort of children born in Canada in 1983-1996 (5 million births) and followed until 2019 (age 23-36 years) to ascertain deaths. We estimated RD and RR for all-cause mortality using log-binomial regressions, and HR for cause-specific mortality using Cox proportional hazards models (censoring individuals who died from other causes) within prespecified age intervals. We accounted for observed confounding using coarsened exact matching on baseline characteristics (e.g., birth year, parental demographics).
Results: During a median (IQR) follow-up of 29 (26-33) years, 72,662 individuals died (5,517 [1.7%] preterm and 49,034 [1.1%] term). PTB was associated with an increased risk of death in all age intervals (Fig 1), with the strongest association seen in early childhood (1-5 years) (RD 0.3%, 95% CI 0.3-0.4%; RR 2.8, 95% CI 2.6-3.0) and the weakest association in the 18-28 age group (RD 0.1%, 95% CI 0.0-0.1%; RR 1.1, 95% CI 1.1-1.2). For cause-specific mortality, PTB was associated with a higher risk of neurological and respiratory disease mortality across all age groups (HR 2.6 (2.2-3.0) and 2.2 (1.7-2.9) respectively, in the 18-36 age group). We also found increased risks of mortality due to cardiovascular, gastrointestinal, and endocrine-related causes and infections. Associations by gestational age (GA) categories showed higher risks with lower GA.
Conclusion: Individuals born preterm are at an increased risk of death from early childhood to their second and third decades of life, with higher risks as GA at birth decreased. These findings suggest the need to consider the long-lasting effects of PTB and may inform preventive strategies.
