Extremely Preterm Infants Have a Higher Fat Mass Percentage in Comparison to Very Preterm Infants at Term-Equivalent Age

Abstract

Background: Early nutritional support of preterm infants is important because it influences long-term health and development. Body composition has an influence on cardiovascular disease, metabolic syndrome, and neurocognitive outcome in the long term. Objective: To assess body composition in preterm infants <32 weeks of gestation at term-equivalent age and to analyze the influence of an optimized nutritional approach. Methods: This is a prespecified secondary outcome analysis of a prospective observational study comparing the body composition in regard to gestational age. The preterm infants were classified according to gestational age as extremely preterm infants (<28 weeks gestation at birth) and very preterm infants (≥28 weeks gestation at birth) and according to weight percentile as appropriate for gestational age and small for gestational age. Body composition was determined by air displacement plethysmography using the PEA POD. The preterm infants obtained nutrition according to the ESPGHAN 2010 Guidelines. Results: Seventy-four preterm infants were analyzed. The mean (SD) gestational age was 28.7 (2.4) weeks, and birth weight was 1,162 (372) g. Fat mass percentage was significantly higher in extremely preterm infants in comparison to very preterm infants [17.0, 95% confidence interval (CI) 15.9-18.1 vs. 15.5, 95% CI 14.7-16.2]. There was no significant difference of fat mass percentage according to weight percentiles. Conclusions: Extremely preterm infants had a significantly higher fat mass percentage compared to very preterm infants at term-equivalent age. There was no significant difference of fat mass percentage according to weight percentiles.

IGF-I, Growth, and Body Composition in Preterm Infants up to Term Equivalent Age

“…Our study cohort had a relatively low incidence of postnatal growth restriction and a relatively high mean fat mass percentage. Others previously showed that preterm infants with postnatal growth restriction (weight SD at term age < −2 SD), had a lower fat mass percentage compared with preterm infants without postnatal growth restriction [ 17 , 18 ]. This could partially explain the higher fat mass percentage in our cohort.…”

Early weight gain trajectories and body composition in infancy in infants born very preterm

“…Following this hypothesis, infants born preterm would simply start this transition “earlier” but at a comparable postnatal age as infants born at term 11 . Two studies comparing infants born “late” and “early” preterm indeed showed that infants born "early" preterm had a higher %FM around 32 to 36 weeks GA and at term equivalent age than infants born “later” preterm 44,45 . In addition to early adaptation, differences in nutrition and early feeding practices between term infants (“natural” ad lib oral feeding) and preterm infants (“artificial” parenteral and tube feeding) will likely play a role in the altered fat trajectory and earlier fat peak seen in preterm infants.…”

Customized Human Milk Fortification Based on Measured Human Milk Composition to Improve the Quality of Growth in Very Preterm Infants: A Mixed-Cohort Study Protocol

“…In addition, we hypothesize that in infants fed target fortified HM, adequate linear and head growth velocities will be achieved [ 37 , 38 ], and adiposity at term-equivalent age will be more similar to that of term-equivalent-age infants [ 28 , 29 ].…”

“…The current literature indicates that extremely and very preterm infants at term-equivalent age have a lower fat-free mass (FFM) and a greater fat mass percentage (FM%), compared with term-equivalent-age infants [ 28 , 29 ]. Reference values for body composition have been described for preterm infants [ 30 , 31 ], but the optimal body composition evolution in those infants remains to be determined.…”