Peripheral blood level of carnitine in neonates and its influencing factors

Abstract

Objective To determine the peripheral blood level of carnitine in neonates and to analyze its influencing factors. Methods All newborns (n=46 250) born in Hunan provincial maternal and child healthcare hospital from 2015 to 2017 were included in this study, except for those primary carnitine deficiency and motherhood carnitine deficiency. Heel prick blood samples were collected 48 hours after birth for determination of carnitine by tandern mass spectrometry. All subjects were grouped according to gender, gestational age, birth weight, number of pregnancies, sample collecting time and whether to be hospitalized. The level of carnitine was analyzed with Mann-Whitney U test, Kruskal-Wallis H test and mutiple linear regression. Results The free carnitine levels of 46 250 neonates were ranged from 5.21 to 56.32 μmol/L, with a geometric mean of 16.05(15.99 to 16.10)μmol/L; males (n=24 375) and females (n=21 875) were 16.68 μmol/L and 15.38 μmol/L; multiple pregnancies (n=3 552) and single pregnancies (n=42 698) were 19.22 μmol/L and 15.81 μmol/L, respectively; hospitalized patients (n=6 409 cases) and non-hospitalized patients (n=3 9841 cases) were 20.10 μmol/L and 15.48 μmol/L respectively. The levels of serum free carnitine were higher in male, multifetal and hospitalized patients (Z=23.739, 30.260, 51.336, P<0.05). Comparing the concentration of free carnitine in 8 groups with different gestational age, 7 groups with different birth weight and 5 groups with different blood collecting age, the differences were statistically significant (H=2369.832, 3032.716, 967.440, P<0.05). Multivariate linear regression showed that all the six factors entered the regression equation, and the sequence was hosp-italization, birth weight, gestational age, number of pregnancies, sex, blood collection age. Conclusions The peripheral blood level of carnitine in neonates is affected by many factors, such as whether to be hospitalized, birth weight, gestational age and so on. Key words: Carnitine/BL; Infant, newborn; Factor analysis, statistical