Body Composition In Preterm Infants Research Articles

Associations of Early Gut Microbiome and Metabolome with Growth and Body Composition of Preterm Infants Within the First 6 Months.

Objectives: This study aimed to explore the associations of growth and body composition with gut microbiome and metabolome in preterm infants. Materials and Methods: A prospective cohort study including 73 human milk-fed very preterm infants was conducted. During hospitalization, fecal samples were collected to detect microbes and metabolites using 16S rRNA gene sequencing and liquid chromatography-mass spectrometry. Growth and body composition indices were measured at term equivalent age (TEA) and 6 months of corrected age (CA). Associations of the fecal microbiome and metabolome profiles with growth and body composition indices, as well as their changes, were analyzed. Results: A higher abundance of Streptococcus was associated with a lower fat-free mass (FFM) z-score at 6 months of CA (p = 0.002) and a smaller increase in FFM z-score from TEA to 6 months of CA (p = 0.018). Higher levels of 3'-sialyllactose and 6'-sialyllactose (6'-SL) in feces were correlated with a lower z-score of percentage body fat (PBF) (p = 0.018 and 0.020, respectively) and a lower z-score of fat mass (p = 0.044 and 0.043, respectively) at 6 months of CA. A higher level of 6'-SL in feces was correlated with a greater increase in FFM z-score from TEA to 6 months of CA (p = 0.021). Conclusions: This study sheds light on the role of specific microbial-host interactions in metabolic changes in preterm infants, indicating the potential role of sialylated human milk oligosaccharides in optimizing body composition.

Anthropometric measurements and body composition of preterm infants born ≤34 weeks at 12-13 months corrected age as compared to term infants.

Growth in the first year of life depends primarily on nutrition. Currently, the infant feeding practices of term babies are being extrapolated for preterms. While extrapolating, it is not clear if corrected age (CA) or chronological age should be used. In preterm infants, born ≤34 week gestation age, this difference may be more than 6 weeks. We studied the growth parameters and body composition of preterm infants born ≤34 week gestation age as compared to that of term infants at 12-13 months CA. The growth of 99 term infants and 170 preterm infants born ≤34 weeks was evaluated at 12-13 months CA. The anthropometric measurements, body mass index (BMI) and skin fold thickness (SFT) at four sites (biceps, triceps, subscapular and suprailiac) were compared in the two groups. The sum of the SFT was taken as a marker of fat mass. At 12-13 months CA, preterm infants had significantly less weight, length and BMI as compared to term babies. The weight and BMI for age Z-scores, weight for length Z-scores and fat mass were also significantly less in preterm babies. The anthropometry measures in preterms (<34 weeks) at 12-13 months CA were significantly lower than that of term infants. In our study population, preterms did not catch up in growth in the first year even when the CA is used for comparison. The causes could be multifactorial and need to be studied further.

Trends in Preterm Body Composition and Neurodevelopmental Outcomes after Discharge

Introduction: Body composition, specifically fat-free mass (FFM), of preterm infants is associated with improved neurodevelopmental outcomes. Little is known about body composition of preterm infants after discharge. Preterm body composition was measured by air displacement plethysmography (ADP) at two time points, inpatient (35–40 weeks postmenstrual age [PMA]) and outpatient (48–58 weeks PMA), with neonatal factors and neurodevelopmental testing at 4–6 months corrected age. We hypothesized increased FFM is positively associated with neurodevelopment. Methods: From 2007 to 2011, 510 infants admitted to the Medical University of South Carolina’s neonatal intensive care unit underwent ADP. A total of 379 of 510 (74%) had anthropometrics at birth, an ADP scan with FFM, fat mass, fat percent z-scores, and an outpatient neurodevelopmental evaluation (CAT/CLAMS, Peabody Gross Motor). Variables were compared using multivariate analyses for body composition measurements. Results: The infants were 32 ± 4.8 weeks gestational age at birth with an average birth weight of 1,697 ± 932 g. Most (56%) infants received maternal milk at discharge. CAT, CLAMS, and gross motor scores had positive correlations with FFM z-scores at inpatient and outpatient ADP (p < 0.05). Receiving maternal milk at discharge was positively associated with cognitive (β = 0.22, p < 0.05) and language scores (β = 0.26, p < 0.05). Conclusion: Increased FFM is associated with improved cognitive, language, and gross motor testing. Maternal milk was positively associated with language and cognitive scores.

450 - Differences in growth and body composition of preterm infants according to race

450 - Differences in growth and body composition of preterm infants according to race

Preterm infant body composition, working memory, and temperament

Altered body composition in preterm infants is associated with risks to cognitive development, but the effect specific to prefrontal cortex (PFC) development is unknown. We were interested in the impact of fat mass (FM) and fat free mass (FFM) gains out to 4 months corrected gestational age (CGA) on PFC development, as indexed by working memory and temperament. This is a prospective observational pilot study recruiting 100 preterm (<33 weeks gestation), appropriate for gestational age, and very low birth weight infants, of which 49 infants met inclusion criteria. Body composition was measured using air displacement plethysmography at hospital discharge and 4 months CGA. Questionnaire based temperament assessments were completed at 12 and 24 months CGA and a working memory assessment was completed at 24 months CGA. Associations between developmental tests and body composition obtained at term and 4 months were analyzed. Increased FM at discharge was associated with increased fear and decreased soothability at 12 months. Increased FM at 4 months was associated with increased activity level, increased distress from limitations at 12 months and decreased attentional shifting, decreased frustration, and decreased inhibitory control at 24 months. Increased FFM at 4 months was associated with increased activity level at 12 months and increased impulsivity and decreased low intensity pleasure at 24 months. In this exploratory pilot study, increased FM out to 4 months and increased FFM after discharge are associated with negative markers of infant temperament. Infant temperament may be sensitive to body composition status at least to 4 months CGA.

Body Composition of Preterm Infants following Rapid Transition to Enteral Feeding

Objective: This study aimed to evaluate body composition at the time of hospital discharge in very preterm infants following rapid transition to full enteral feeding. Study Design: We conducted a prospective, observational, cross-sectional study and included 105 preterm infants <32 gestational age or birth weight <1,500 g, born between April 2015 and December 2020, following rapid transition to full enteral feeding (≥140 mL/kg/day). Fat mass/total body mass (BF%) and fat-free mass (FFM) were measured at the time of hospital discharge using air displacement plethysmography. Results: Median and interquartile range (Q1–Q3) of gestational age at birth (GA) was 27.3 (26.1–28.7) weeks and birth weight 845 (687–990) g. Time to reach full enteral feeding was 5 (5–7) days. At 37.6 weeks (36.1–39.0) postmenstrual age (PMA), BF% was 17.0% (14.9–19.8) and FFM 2,161 g (1,966–2,432). BF% was not associated with GA, and not different between small and appropriate for gestational age infants. FFM was significantly lower in infants born small for gestational age. Conclusions: Following rapid transition to full enteral feeding, FFM and BF% at discharge were similar to other preterm populations. BF% and FFM were not associated with GA at birth but with PMA at measurement. FFM was lower and BF% higher compared to term infants at birth, suggesting diminished parenchymal growth in preterm infants. Continued monitoring of body composition, metabolic health, and neurological development is needed to study long-term effects.

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

ContextThere are concerns that a higher fat mass in the early life of preterm infants is associated with adverse cardiometabolic outcomes in young adulthood.ObjectiveTo investigate the role of IGF-I and growth in determining body composition of preterm infants at term equivalent age.MethodsAn observational study was conducted from August 2015 to August 2018. From birth to term equivalent age, IGF-I levels were measured bi-weekly and growth was assessed weekly. At term equivalent age, body composition was assessed through air displacement plethysmography; 65 infants with a gestational age of 24 to 32 weeks were assessed at term equivalent age, of whom 58 completed body composition measurement. The main outcome measures were fat (free) mass (g) and fat (free) mass percentage at term equivalent age.ResultsIn the first month of life, each 0.1 nmol/L per week increase in IGF-I was associated with a 465 g (SE 125 g) increase in fat free mass. A greater increase in weight SDS in the first month of life was associated with a higher fat free mass percentage (B 200.9; 95% CI, 12.1-389.6). A higher head circumference SDS was associated with more fat free mass (r = 0.46; 95% CI, 0.21-0.65). However, a greater increase in weight SDS up to term equivalent age was associated with a lower fat free mass percentage (B −55.7, SE 9.4).ConclusionThese findings suggest that impaired growth in the first month of life is associated with a less favorable body composition at term equivalent age.

Different feeding regimens were not associated with variation in body composition in preterm infants

Aim The aim was to determine body composition and growth in preterm infants based on two different feeding regimens and to assess how standard and individual fortification (IF) affect energy and protein intake. Body composition was assessed at full term and at four months corrected age. Methods Sixty preterm infants born before gestational week 32 were randomized either to IF of mother’s breast milk after it had been analyzed or to standard fortification (SF) of mother’s breast milk based on the average protein and energy content of breast milk. Body composition was measured at full term and at four months corrected age, using air displacement plethysmography. Growth rate and nutritional intake analyses were also conducted. Results At 40 weeks gestational age, there was no difference between weight (g) (IF 3056 ± 472 vs. SF 3119 ± 564), body fat (%) (IF 19 ± 3.3 vs. SF 21 ± 5.6), fat mass, or fat-free mass between the two groups. Furthermore, there was no difference between the groups in weight, length, head circumference, or body composition at four months corrected age. Conclusions Fortification based on breast milk analysis may not improve growth in preterm infants compared to SF. However, both groups were smaller and had a different body composition at term corrected age compared to infants born at term.

Associations of early nutrition with growth and body composition in very preterm infants: a prospective cohort study.

To investigate impacts of early postnatal macronutrient intakes on growth and body composition of preterm infants within the first 6 months. One hundred and thirty-three very preterm (VPT) and/or very low birth weight (VLBW) infants were consecutively included. Enteral and parenteral macronutrient intakes during the first 28 days were recorded and average daily intakes were calculated. Growth was measured at birth, term age, and 6 months of corrected age (CA). Body composition was examined by air displacement plethysmograph at term age and 6 months of CA. Associations of nutrient intakes with growth and body composition over time were analyzed using generalized estimating equation. After adjusting for covariates, higher daily protein, lipid, and energy intake during the first 28 days was associated with higher weight at term age for every 1 g/kg/day increment of protein and lipid intake, and every 10 kcal/kg/day increment of energy intake was associated with 0.50 (95% CI 0.04, 0.96), 0.29 (95% CI 0.07, 0.51), and 0.27 (95% CI 0.10, 0.44) higher weight z-score, respectively. Higher protein intake was associated with lower z-score of fat mass (FM, β = -1.88, 95% CI -3.53, -0.23) and percentage of body fat (PBF, β = -2.18, 95% CI -3.98, -0.39) at 6 months of CA, but higher lipid and carbohydrate intake was associated with higher FM and PBF z-scores at 6 months of CA. Macronutrient intakes during the first month of life have impacts on growth and body composition before 6 months of age. Higher daily protein intake is associated with a better growth and healthier body composition for VPT/VLBW infants.

Effect of tactile/kinesthetic massage therapy on growth and body composition of preterm infants.

Massage therapy (MT) improves growth parameters in preterm infants. The growth of lean mass rather than fat mass has been associated with better long-term outcomes. We aimed to study the effect of tactile/kinesthetic MT on growth and body composition parameters in preterm infants. Preterm (< 32weeks gestation) infants were randomly assigned at corrected gestational age of 35weeks to receive 3 consecutive, 15-min, sessions of MT over 5days or routine care. Primary outcome was mean daily weight gain. Secondary outcomes included anthropometric measurements and body composition parameters assessed by dual X-ray absorptiometry (DXA) scan. Out of 218 infants screened, 86 were eligible and 60 infants (30 in each group) were recruited after parental consent. MT was associated with significant increase in daily weight gain [19.3 (10-34.3) versus 6.2 (2.5-18.4)g/day, p = 0.01] and growth velocity [12.5 (6-21) versus 3.6 (1.6-12.6)g/kg/d, p = 0.01] compared with routine care. Infants on MT showed significant increase in total body mass, fat mass (total/legs), lean mass (total/arms/legs/trunk), and bone mineral density (arms/legs/trunk) values compared with routine care group. In conclusions, MT improves growth quality as evident by increased total and regional lean masses, increased bone mineral density, and peripheral rather than central fat distribution. What is known on this subject? • Massage therapy (MT) for preterm infants leads to achievement of faster independent oral feeding, increased weight gain, less stress, less response to pain, less occurrence of sepsis, and shorter hospital stay. • Growth of lean mass rather than fat mass has been associated with better long-term outcomes. What this study adds? • Tactile/kinesthetic massage therapy in preterm infant is associated with improved growth parameters and anthropometric measures. • Tactile/kinesthetic massage therapy increased total body mass, fat mass (total/legs), lean mass (total/arms/legs/trunk), and bone mineral density (arms/legs/trunk) values.

Serial assessment of fat and fat-free mass accretion in very preterm infants: a randomized trial.

Background:Clinicians could modify dietary interventions during early infancy by monitoring fat and fat-free mass accretion in very preterm infants.Methods:Preterm infants were randomly assigned to either having reports on infant body composition available to the clinicians caring for them (intervention group) or not having reports available (control group). All infants underwent serial assessments of body composition by air-displacement plethysmography before 32 weeks of postmenstrual age (PMA) and at 36 weeks PMA. The primary outcome was percent body fat (%BF) at 3 months of corrected age (CA).Results:Fifty infants were randomized (median gestational age: 30 weeks; mean ± SD birth weight: 1387 ± 283 g). The mean %BF increased from 7 ± 4 before 32 weeks PMA to 20 ± 5 at 3 months CA. The differences in mean %BF between the intervention group and the control group were not statistically significant at 36 weeks PMA (14.5 vs. 13.6) or 3 months CA (20.8 vs. 19.4). Feeding practices and anthropometric measurements during hospitalization did not differ between groups.Conclusions:Serial assessments of body composition in both intervention and control groups showed consistent increments in %BF. However, providing this information to clinicians did not influence nutritional practices or growth.

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

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.

Growth patterns and body composition in former extremely low birth weight (ELBW) neonates until adulthood: a systematic review.

Preterm infants are obviously born lighter and shorter, with smaller head circumferences than normal birth weight term born neonates. They also have a different body composition. Compromised growth is associated with adverse health outcomes. Both growth retardation and accelerated growth are suggested to cause metabolic, cardiovascular, and renal complications. Reviews regarding growth and body composition in preterm infants often do not differentiate between birth weight and gestational age. The purpose of this systematic review is to assemble growth data, specific in extremely low birth weight children. Different databases were searched for studies regarding growth and body composition in former extremely low birth weight infants until adulthood. We compared height, weight, head circumference, body mass index, fat mass, lean mass, fat distribution, and body water to matched normal birth weight controls and the World Health Organization growth charts. Studies consistently reported that former extremely low birth weight neonates experience a period of accelerated postnatal growth, but they achieve lower anthropometric parameters than normal birth weight children. There is no consensus about differences in body composition and how to measure this.Conclusion: Although extremely low birth weight infants exhibit a period of catch-up growth, their growth remains retarded later in life. Further research is needed to investigate body composition and the associated risk of cardiovascular diseases or metabolic syndrome.What is Known:• Extremely low birth weight infants have lower anthropometric parameters and a different body composition at birth and term-corrected age than normal birth weight infants.• Former extremely low birth weight infants also have a higher risk on adverse cardiovascular health outcomes in later life.What is New:• After hospital discharge, extremely low birth weight neonates remain smaller and probably also lighter, with smaller head circumferences at each corrected age throughout childhood and adolescence when compared to normal birth weight infants or the World Health Organization growth charts. It is not clear whether extremely low birth weight infants reach a lower or similar body mass index score as normal birth weight infants.• There is a lack of (long-term) information on body composition in extremely low birth weight infants.

Racial Disparities in Body Composition of Preterm Infants (P21-049-19)

Abstract Objectives At term-equivalent age, preterm infants have higher % body fat (%BF) than infants born at term. This difference in %BF is often the result of exposure to enriched postnatal diets prescribed to promote rapid weight gain among preterm infants. Because rapid weight gain during infancy and obesity are more prevalent among blacks than among whites, racial disparities in the development of adiposity expressed as %BF need to be explored. The purpose of this study was to compare %BF in two major racial groups using normative data as reference. Methods We analyzed data from a prospective study that assessed body composition in preterm infants using air displacement plethysmography (PeaPod®). After stratifying data according to race, we analyzed differences between mean %BF values of preterm infants at the time of hospital discharge and compared these differences to existing references of %BF in preterm infants. A linear regression analysis was performed to account for differences in baseline characteristics. Results We assessed body composition in 84 preterm infants, of which 47 were black and 37 were white. Mean birthweight was 1471 g and median gestational age was 30 weeks. In preterm infants assessed at the time of hospital discharge, mean %BF was 14.6 ± 3.6 (14.5 ± 2.9 in white infants and 14.6 ± 4.1 in black infants; P = 0.90). The measured %BF at the time of hospital discharge was higher than the expected %BF at equivalent postmenstrual age (mean difference: 4.7 ± 3.5; P &amp;lt; 0.05). After adjustment for BW, GA, sex, and length of hospital stay, this difference between measured and expected %BF was not significantly higher among black infants compared to white infants (5.1 vs. 4.2; P = 0.28). Conclusions Black race is not associated with higher %BF at the time of hospital discharge in preterm infants. If racial disparities in body composition exist among former preterm infants, those differences may occur after hospital discharge. Both black and white preterm infants exposed to enriched postnatal diets develop higher than expected %BF by the time of hospital discharge. Funding Sources None.

Human milk protein vs. formula protein and their use in preterm infants.

We review the current available evidence on the metabolic fate of human milk proteins and their potential clinical implications for growth and body composition development vs. those of formula proteins in preterm infants. The decreased content of human milk protein in preterm mothers throughout lactation might contribute to the reduced growth reported in exclusively human milk-fed infants compared with that of formula-fed infants. Recent studies have demonstrated that preterm infants are capable of degrading human milk proteins regardless of their degree of prematurity or postnatal age, with limited contribution from milk proteases to protein digestion. The nitrogen balance of fortified human milk-fed preterm infants is higher than that of formula-fed preterm infants. Moreover, the growth of human milk-fed preterm infants appears to be accompanied by fat-free mass deposition. Provided that adequate protein and energy intakes are delivered, human milk enhances protein use rather than oxidation as well as promotes tissue growth, leading to preferential fat-free mass deposition and contributing to the recovery of the body composition in preterm infants. Human milk feeding should be supported and promoted for all preterm mother-infant pairs.

The Effect of Human Milk on Modulating the Quality of Growth in Preterm Infants.

Introduction: Human milk is the optimal nutrition for preterm infants. When the mother's own milk is unavailable, donor human milk is recommended as an alternative for preterm infants. The association among early nutrition, body composition and the future risk of disease has recently attracted much interest. The aim of this study was to investigate the effect of human milk on the body composition of preterm infants.Materials and Methods: Very low birth weight infants (VLBW: birth weight <1,500 g) with a gestational age (GA) between 26 and 34 weeks were included. Clinical data, anthropometric measurements and nutritional intake in terms of the volume of human milk were extracted from computerized medical charts. The human milk intake was expressed as a percentage of target fortified donor human milk and/or target fortified fresh mother's milk, compared with the total volume of milk intake during the hospital stay. All included infants underwent anthropometric measurements and body composition analysis (expressed as fat-free mass percentage) at term corrected age (CA) by air-displacement plethysmography. A comparison between infants fed human milk at <50% (group 1) and infants fed human milk at ≥50% of the total volume of milk intake (group 2) was conducted. Multiple linear regression analyses were conducted to explore the modulating effect of fortified human milk on fat-free mass at term CA.Results: Seventy-three VLBW infants were included in the study. The mean weight and GA at birth were 1,248 ± 198 g and 30.2 ± 2.0 weeks, respectively. No differences were found regarding anthropometric measurements at birth, at discharge and at term CA between the two groups. The mean fortified human milk intake was 34.9 ± 12.5 and 80.9 ± 15.5% in groups 1 and 2, respectively (p < 0.001).A multiple regression analysis corrected for sex and birth weight demonstrated that intake of ≥50% fortified human milk was associated with a higher fat-free mass percentage at term CA than intake of <50% fortified human milk.Conclusion: The use of target fortified human milk modulated growth and improved growth quality in vulnerable preterm infants. Thus, the use of donor human milk should be encouraged when fresh mother's milk is insufficient or not available.

Growth and body composition in preterm newborns with bronchopulmonary dysplasia: a cohort study.

BPD. Anthropometric measurements were performed at birth and at 1 month of infant corrected age. Body composition was measured using an air displacement plethysmography (ADP) (PEA POD®) at 1 month of infant corrected age. Results Ninety-five newborns were eligible, of which 67 were included, 32.8% of them with BPD. Newborns with BPD presented lower gestational age at birth, greater need for resuscitation in the delivery room, received parenteral nutrition (PN) for a longer period of time, achieved lower weights during hospital stay and required more time to reach a full enteral diet. No statistically significant differences were observed in relation to anthropometric measurements and body composition at 1 month of infant corrected age between the groups with and without BPD. Conclusion This study, unlike previous ones, has shown that children who developed BPD were able to regain growth, as measured by anthropometric measures, with no change in body composition at 1 month of infant corrected age.

Does type of feeding affect body composition in very low birth weight infants? – A prospective cohort study

BackgroundThe aim of the study was to analyse body composition of preterm infants fed with either breast milk or formula compared to a control group of full-term newborns. MethodsFifty-three newborns were enrolled: a group of 34 very low birth weight (VLBW) preterm newborns subdivided into a formula-fed (n = 23; group A) and breast milk-fed (n = 11; group B) group, and a control group of 19 full-term infants (group C). Their body composition was assessed by a bioelectrical impedance analysis (BIA) either at the estimated time of birth in the VLBW group or during the 1st week of life in the full-term group. ResultsThere was no difference in body weight or length between any of the three studied groups. However, we discovered that fat free mass (% FFM) was lower (83.5% vs. 85.5%; p < 0.01), while fat mass (% FM) was higher (16.4% vs.14.5%; p < 0.01) in group A compared to full-term newborns. There were no such differences in FFM (84.3% vs. 85.5%; p = 0.13) or FM (15.7% vs. 14.5%; p = 0.13) between group B and control. ConclusionTo sum up, the VLBW infants fed with breast milk shared similar body composition with the full-term infants, while the formula-fed VLBW developed higher amounts of adipose tissue and lower amounts of fat-free mass. This is the first study to expose differences in fat tissue content attributed to type of provided nutrition, which has become significant as early as estimated time of birth despite the comparable weight.

Body composition in preterm infants with intrauterine growth restriction: a cohort study.

AbstractAims:The comparison of body composition parameters between the small for gestational age (SGA) and appropriate for gestational age (AGA) at term, 1, 3 and 5 months corrected ages in very preterm infants.Methods:This cohort study included 92 preterm infants at term age, younger than 32 weeks or &lt;1500 g, classified in two groups: SGA and AGA. Anthropometry and body composition, estimated by air displacement plethysmography, were evaluated at the corrected ages: term and 1, 3, and 5 months. We used the lean mass/fat mass index (LM/FM) at each time point and the weight, length and head circumference SDS gain between the time points.Results:At term age, the SGA preterm infants had less lean mass (g), fat mass (g) and percent fat mass but a greater LM/FM index than AGA infants (P&lt;0.001). At 1 month corrected age the LM/FM index and percent fat mass between the groups became similar. Lower lean mass persisted up to 3 months in the SGA group [4004 g (3256–4595) vs. 4432 g (3190–6246), P&lt;0.001]. During the first month corrected age, the weight SDS gain was higher in SGA preterm infants when compared to AGA preterm infants. However, the SGA preterm infants remained lighter, shorter and with smaller head circumferences than the AGA preterm infants until 3 months of corrected age.Conclusions:The greater lean tissue deficits and an earlier “catch-up” in fat in the SGA group can reflect growth patterns variability since the early life.

Body Composition in Very Preterm Infants: Role of Neonatal Characteristics and Nutrition in Achieving Growth Similar to Term Infants

Background: The identification of factors involved in the postnatal growth of preterm infants will help achieve growth similar to that of term infants. Objectives: As per protocol: to compare body composition in very preterm infants at term-corrected age (TCA) with that in term infants, and to explore relationships between neonatal characteristics and body composition in preterm infants. Methods: Anthropometry, nutritional characteristics, and neonatal outcomes were prospectively collected in 26 preterm (<29 weeks) and 33 term (37-40 weeks) infants. Body composition using dual-energy X-ray absorptiometry (DXA) was measured at TCA in preterm infants and between days 7 and 10 in term infants. Results: Parenteral nutrition in preterm infants provided a mean of 2.9 ± 0.2 and 2.1 ± 0.5 g/kg/day of intravenous amino acids and lipids, respectively, during the first week of life. The mean weight gain velocity from birth to DXA assessment was 12.1 ± 1.4 g/kg/day. Compared with term infants, preterm infants at TCA were shorter and lighter, with a smaller head circumference, a lower weight estimated by DXA (2,960 ± 552 vs. 3,843 ± 377 g), and increased skinfold thicknesses. Fat mass percent (13.9 ± 5.4%) and lean mass percent (84.7 ± 5.6%) in preterm infants were similar to those in term infants (14.7 ± 3.5 and 83.5 ± 3.6%, respectively). Neonatal weight gain velocity in preterm infants was positively associated with lean mass (grams). Conclusion: Subcutaneous fat is increased in preterm infants. Higher protein intake in preterm infants might increase weight gain velocity and achieve a lean mass comparable to that of term infants.