Increased risk of rickets but not fractures during childhood and adolescence following necrotizing enterocolitis among children born preterm in Sweden.

Background: The aim was to clarify whether children born preterm with a history of necrotizing enterocolitis (NEC) had an increased risk of rickets, fractures, and/or vitamin D deficiency during childhood and adolescence compared to controls without NEC, matched for gestational age.

Methods: All infants born in Sweden between 1987 and 2009 with a gestational age <32 + 0 weeks and a diagnosis of NEC were identified. Totally, 465 children with a history of NEC and 2127 controls were included. International Classification of Diseases codes for all categories of fractures, rickets, vitamin D deficiency, and malnutrition were analyzed.

Results: In total, 94 of the 465 children with NEC died within 28 days. Of the 2127 controls, 288 died within 28 days. Among the remaining 371 NEC cases, 39 fracture occasions were identified. The 1839 controls had 204 fracture occasions. There was no significant difference in fractures. Rickets was diagnosed in 11 (3%) of the children with a history of NEC compared to 21 (1%) of the controls (odds ratio 2.65, 95% CI 1.26-5.53, p = 0.007).

Conclusions: This study showed an increased risk of rickets but not fractures during childhood and adolescence in children born preterm and with a history of NEC, compared to matched controls.