IARC 60th Anniversary - 19-21 May 2026
Session : Childhood Cancer Research in Action: Bridging Population Science and Discovery
Preterm birth, major birth defects and childhood cancer risk: a large Scandinavian population-based case-control study
DALTVEIT D. 1,2, KLUNGSØYR K. 1,3, ENGELAND A. 1,3, GISSLER M. 4,5, GLIMELIUS . 6,7, MADANAT-HARJUOJA L. 8,9, ORDING A. 10, SØRENSEN H. 10, TROISI R. 11, BJØRGE T. 1,12
1 Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; 2 Norwegian Quality Registry of Cleft Lip and Palate, Surgical Clinic, Haukeland University Hospital, Bergen, Norway; 3 Division of Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway; 4 Department of Data and Analytics, Finnish Institute of Health and Welfare, Helsinki, Finland; 5 Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden; 6 Department of Immunology, Genetics and Pathology, Cancer Precision Medicine, Uppsala University, Uppsala, Sweden; 7 Department of Medicine Solna, Clinical Epidemiology Division, Karolinska Institutet, Stockholm, Sweden; 8 Finnish Cancer Registry, Helsinki, Finland; 9 Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; 10 Department of Clinical Epidemiology, and Center for Population Medicine, Aarhus University Hospital and Aarhus University, Aarhus, Denmark; 11 Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, United States; 12 Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway
Background
Preterm birth (<37 gestational weeks) is associated with short- and long-term mortality and morbidity. Evidence regarding the association between prematurity and childhood cancer risk, however, remains limited.
Objectives
To examine the association between preterm birth and childhood cancer risk, and to assess whether this association is modified by the presence of birth defects.
Methods
We conducted a population-based nested case–control study including 17,320 cancer cases (0-19 years) and 173,338 matched controls born between 1967 and 2014, using nationwide Scandinavian health registries. We estimated relative risk of in children born preterm versus term using logistic regression to calculate odds ratios (ORs) with 95% confidence intervals (CIs). Effect modification by birth defects on the multiplicative scale was evaluated by including a product term between preterm birth and birth defects in the regression models, and additive interaction was assessed by estimating the relative excess risk due to interaction (RERI).
Results
The median age at cancer diagnosis was 8 years, and 35.8% of cases were diagnosed before age 5. Preterm birth occurred in 6.2% of cases and 5.6% of controls and birth defects were more frequent among cases (4.1% vs. 2.0%). Preterm birth was associated with an increased overall cancer risk (OR=1.10, 95% CI: 1.03-1.17), after adjustment for country, birth year, sex, maternal age and birth defect. Elevated risks were observed for hepatic tumors, soft tissue sarcoma, and leukemia. Associations varied by birth defect status: preterm birth showed a modest increase among children without birth defects (1.06, 0.99-1.13) but a stronger association among those with defects (1.59, 1.28-2.02). Interaction was present on both additive and multiplicative scales.
Conclusion
Prematurity may increase the risk of childhood cancer, particularly leukemia, hepatic tumors, and soft tissue sarcoma. The association between being born preterm and risk of cancer was more pronounced among children with birth defects.