El peso para la longitud en pretérminos tardíos evaluados con impedancia bioélectrica se asocia a variables antropométricas

Abstract

Introduction The fat mass is greater in late preterm than full term infants at 1 month post birth, which may be an additional risk factor for metabolic syndrome in adulthood. Objectives To evaluate body composition (BC) in late preterm infants using bioelectrical impedance analysis to determine which anthropometric parameters are associated with BC. Our hypothesis was that weight-for-length is associated with the length-normalized fat mass index (FMI) at 1 year of life. Materials and methods We carried out a prospective cohort study in 2 groups: late preterm infants and full term infants. We obtained BC data by bioelectrical impedance analysis. We calculated the fat mass, FMI, fat-free mass (FFM) and length-normalized FFM index at 1, 6 and 12 months of life. After, we assessed the association of the FMI with anthropometric parameters using multiple linear regression analysis. Results The study included 97 late preterm and 47 full term infants, although at 12 months of life, the BC assessment was performed on 66 and 33 infants, respectively. Late preterm infants, compared to full term infants, had a higher FFM at 1 month (4013 g vs. 3524 g), a higher weight velocity at 6 months (5480 g vs. 4604 g) and a lower FFM (7232 g vs. 7813 g) and FFM index (12.55 vs. 13.26) at 12 months of life. The multivariate regression analysis showed that the weight-for-length z-core at 12 months was positively associated with the FMI at 12 months in all infants. Conclusion The weight-for-length z-score at 12 months is strongly associated with the FMI at 1 year of life. Further studies are needed to investigate whether an increment in this anthropometric parameter may modulate the risk of chronic diseases.