Preterm birth and risk of bone fractures during childhood and early adulthood

People born preterm have reduced bone mineral density, subnormal peak bone mass, and an increased risk of osteoporosis. Whether this translates to increased risk of bone fractures is uncertain. We assessed fracture risk from childhood to early adulthood in relation to gestational age and sex by conducting a nationwide register-linkage cohort study comprising all 223 615 liveborn (1/1987- 9/1990) singletons (9161, 4.1%, preterm) in Finland. Cox regression models provided hazard ratios (HR) for fracture diagnosis in public specialty healthcare in both first and recurrent event settings during the whole follow-up (0-29 yr), and during different age periods (0-4/5-9/10-29 yr). Gestational age was considered categorical (full-term, 39-41 weeks, reference). A total of 39 223 (17.5%) children or young adults had at least one fracture. In analyses not stratified by sex, only extremely preterm birth (