Gestational age at birth and the risk of disability pension in early adulthood: a whole-population register study of people born in Finland in 1987–90

BACKGROUND: Preterm (<37 weeks), early-term (37-38 weeks), or post-term (42 weeks) birth may elevate the risk of mental, neurodevelopmental, and cardiopulmonary disease in adulthood, potentially impacting work capacity. METHODS: We examined the association between gestational age and early disability pension (DP) among 228 572 Finnish individuals born between 1 January 1987 and 30 September 1990. We identified the first DP decision from ages 16 to ∼32 years (2003-20) by using linked birth and DP records, including timing and diagnosis. Adjusted hazard ratios (HRs) with 95% confidence intervals were estimated by using Cox regression, with full-term birth (39-41 weeks) as the reference. RESULTS: A total of 9224 individuals (4.0%) received DPs. Adjusted for sex and birth year, the HRs for DP by gestational age groups of 23-31, 32-33, 34-36, 37-38, and 42 weeks were 5.20 (4.52-5.99), 2.47 (2.04-3.00), 1.55 (1.41-1.70), 1.22 (1.16-1.29), and 1.12 (1.01-1.25). Among preterm adults, the most common diagnoses included cerebral palsy, intellectual disability, depression, and schizophrenia. For early-term and post-term adults, depression and schizophrenia were the most frequent. CONCLUSION: Preterm, early-term, and post-term births were associated with early DPs, with slightly different diagnostic profiles. The risk was highest among those born very preterm (<32 weeks). High-quality perinatological care is crucial regarding future careers and societal costs.