Carnitine longitudinal pattern in preterm infants <1800 g body weight: a case–control study

The aim of this study is to investigate free carnitine (C0) and total acylcarnitine levels (AC) in preterm infants with BW < 1800 g and the relationship with neonatal and perinatal factors. Ninety-three thousand two hundred and ninety-three newborns were screened between 2011 and 2013. Dried blood samples (DBS) were collected at 48–72 h, 14, and 30 days of age. We studied 92 consecutive preterm (BW < 1800 g) infants with low carnitine levels at 30 days of life (Group 1). As controls, we included the first 92 cases (BW < 1800 g) with normal carnitine levels (Group 2) and another 92 at or near-term newborns with BW > 1800 g (Group 3). Compared to 48–72 h levels, C0 and AC decreased at 14 and 30 days of life in Groups 1 and 2 (p < 0.001). In Group 2, the percentage of children with carnitine-free parenteral nutrition (PN) and BW < 1000 g was lower than in Group 1 (p < 0.001). Only in Group 2 did C0 increase at 30 days (p < 0.001). The multivariate regression analysis confirmed the influence of body weight and type of nutrition on C0 and AC. Body weight and type of nutrition influenced the carnitine longitudinal pattern.