BACKGROUND: Birth length is correlated to height at 2 years and is a predictor of adult height. However, little is known about the relationship between length growth during neonatal hospitalization and height at 2 years. OBJECTIVES: The objective was to determine the relationship between length growth during neonatal hospitalization and height at 2 years in preterm infants. METHODS: A total of 1,760 preterm infants of less than 35 weeks of gestational age were included. Neonatal length growth was defined by the difference between length Z-scores at discharge and at birth according to Olsen curves. We calculated the odds ratios (OR) before and after adjustment for the risk of being in the 1st quintile of the height Z-score at 2 years. RESULTS: Height at 2 years was positively associated with birth length (p < 0.001) and with neonatal length growth (p < 0.001), whereas birth length and neonatal length growth were inversely correlated (p < 0.001). The risk of being in the 1st quintile of the height Z-score at 2 years was significantly associated with birth length (adjusted OR = 0.43, 95% CI: 0.38-0.49, for one Z-score) and with neonatal length growth (adjusted OR = 0.66, 95% CI: 0.56-0.76, for one Z-score) before and after adjustment for perinatal variables. CONCLUSIONS: In addition to birth length, neonatal length growth was associated with height at 2 years. These findings point to the need for a close follow-up of the length of preterm infants during hospitalization, so as to start an early management of those patients.
BACKGROUND: Birth length is correlated to height at 2 years and is a predictor of adult height. However, little is known about the relationship between length growth during neonatal hospitalization and height at 2 years. OBJECTIVES: The objective was to determine the relationship between length growth during neonatal hospitalization and height at 2 years in preterm infants. METHODS: A total of 1,760 preterm infants of less than 35 weeks of gestational age were included. Neonatal length growth was defined by the difference between length Z-scores at discharge and at birth according to Olsen curves. We calculated the odds ratios (OR) before and after adjustment for the risk of being in the 1st quintile of the height Z-score at 2 years. RESULTS: Height at 2 years was positively associated with birth length (p < 0.001) and with neonatal length growth (p < 0.001), whereas birth length and neonatal length growth were inversely correlated (p < 0.001). The risk of being in the 1st quintile of the height Z-score at 2 years was significantly associated with birth length (adjusted OR = 0.43, 95% CI: 0.38-0.49, for one Z-score) and with neonatal length growth (adjusted OR = 0.66, 95% CI: 0.56-0.76, for one Z-score) before and after adjustment for perinatal variables. CONCLUSIONS: In addition to birth length, neonatal length growth was associated with height at 2 years. These findings point to the need for a close follow-up of the length of preterm infants during hospitalization, so as to start an early management of those patients.