Comparison of growth patterns in the first year of life between term small for gestational age and appropriate for gestational age South Indian infants.

BACKGROUND: Early life growth trajectories of Indian small for gestational age (SGA) infants are sparse. This study aimed to compare longitudinal growth in appropriate for gestational age (AGA) and SGA infants during their first year of life. METHODS: Apparently healthy term infants (52 SGA, 154 AGA) were recruited at birth and followed up till 1 year. Parental, sociodemographic characteristics and feeding patterns were recorded. Anthropometric measurements were assessed at birth, 3, 6, 9 and 12 months of age; Z scores and growth velocity at 3-month intervals were computed. Longitudinal measurements were compared between the two groups, using the two-way Friedmans test. Median regression with mixed effects was used to adjust covariates; p value <0.05 was considered statistically significant. RESULT: AGA infants had significantly higher median weight (kg) (2.87 (2.67, 3.04) vs 2.39 (2.25, 2.54)) at birth, (7.08 (6.50, 7.54) vs 6.49 (6.13, 6.78)) at 6 months, (8.64 (7.92, 9.14) vs 7.90 (7.36, 8.54)) at 12 months, median length (cm) ((48.10 (47.20, 49.30) vs 46.75 (45.43, 47.50)) at birth, (65.50 (64.23, 66.98) vs 63.33 (62.26, 65.28)) at 6 months, (73.30 (71.58, 74.66) vs 71.55 (70.00, 73.30)) at 12 months. SGA infants had comparable weight velocity at all intervals except 9-12 months (6.62 (6.45, 6.79) vs (6.70 (6.51, 6.85)), being significantly higher than AGA infants. Differences in skinfold thicknesses between groups were observed only at birth. Exclusivity of breast feeding was significantly higher at 3 months in AGA, compared to SGA infants (80.9% vs 57.8%). Length velocity was comparable at all ages between groups. Sexual dimorphism was observed in the growth velocities of both groups. CONCLUSION: SGA infants grew in parallel to AGA infants, having significantly lower anthropometric measurements at all time points. However, growth velocities were similar; SGA infants had significantly higher weight velocity from 9 to 12 months. Longitudinal studies beyond 1 year of age, using body composition are needed to determine the quality of growth in Indian infants.

Body composition of infants at 6 months of age using a 3-compartment model.

BACKGROUND/OBJECTIVES: Two compartment (2 C) models of body composition, including Air Displacement Plethysmography (ADP) and Deuterium Dilution (DD), assume constant composition of fat-free mass (FFM), while 3-compartment (3 C) model overcomes some of these assumptions; studies are limited in infants. The objective of the present study is to compare 3 C estimates of body composition in 6-mo. old infants from Australia, India, and South Africa, including FFM density and hydration, compare with published literature and to evaluate agreement of body composition estimates from ADP and DD. METHODS: Body volume and water were measured in 176 healthy infants using ADP and DD. 3C-model estimates of fat mass (FM), FFM and its composition were calculated, compared between countries (age and sex adjusted) and with published literature. Agreement between estimates from ADP and DD were compared by Bland-Altman and correlation analyses. RESULTS: South African infants had significantly higher % FM (11.5%) and density of FFM compared to Australian infants. Australian infants had significantly higher % FFM (74.7 ± 4.4%) compared to South African infants (71.4 ± 5.0) and higher FFMI (12.7 ± 0.8 kg/m2) compared to South African (12.3 ± 1.2 kg/m2) and Indian infants (11.9 ± 1.0 kg/m2). FFM composition of present study differed significantly from literature. Pooled three country estimates of FM and FFM were comparable between ADP and DD; mean difference of -0.05 (95% CI: -0.64, +0.55) kg and +0.05 (95% CI: -0.55, +0.64) kg. CONCLUSIONS: 3C-model estimates of body composition in infants differed between countries; future studies are needed to confirm these findings and investigate causes for the differences.

Comparison of Anthropometry and Body Composition Using Air Displacement Plethysmography in Term Small for Gestational Age and Appropriate for Gestational Age Neonates.

BACKGROUND: Small for gestational age (SGA) neonates are prone to growth deficits in early life, which may be associated with later life metabolic abnormalities. OBJECTIVES: To compare anthropometry and body composition using air-displacement plethysmography (ADP) in term SGA and appropriate for gestational age (AGA) neonates, and assess if sexual dimorphism existed in estimates of body composition. STUDY DESIGN: Cross-sectional analytical study. PARTICIPANTS: 413 term neonates (91 SGA and 322 AGA) at birth (≤7days). METHODS: Neonatal anthropometry and body composition were measured using ADP. Length corrected fat mass index (FMI) and fat free mass index (FFMI) were calculated. OUTCOME: Anthropometry and body composition estimates of SGA and AGA neonates, segregated by sex. RESULTS: The mean (SD) birth weight of SGA and AGA neonates was 2.5 (0.2) kg and 3.1 (0.3) kg, respectively. SGA neonates had significantly lower % body fat (BF) (2.0%), fat mass (94.4 g), fat free mass (FFM) (349.7 g), FMI (0.34 kg/m2), and FFMI (0.76 kg/m2), but higher %FFM (2.0%) compared to AGA neonates (P<0.001). Males had significantly higher %FFM [91.2 (3.1) vs 90.2 (3.5); P=0.001], FFM [2604 (280) vs 2442 (233) g; P<0.001], and FFMI [11.1 (0.8) vs 10.8 (0.8) kg/m2; P=0.005], but lower % BF [8.8 (3.1) vs 9.8 (3.5); P=0.001] and FMI [1.1(0.4) vs 1.2 (0.5) kg/m2; P=0.008], compared to females. CONCLUSIONS: Accurate estimates of body composition in neonates at birth suggest significantly lower body fat and fat free mass in SGA compared to AGA, with sexual dimorphism.