Body composition from birth to 2 years in term healthy Indian infants measured by deuterium dilution: Effect of being born small for gestational age and early catch-up growth

Abstract

Objectives South Asian body composition is characterized by higher body fat at any given BMI. While this does not occur during fetal growth, it is important to understand if inappropriate fat accretion then begins in the first 2 years in Indian infants. Methods The fat mass (FM) and fat-free mass (FFM) of healthy term newborns was evaluated at 12 days, 3.5 months, 1 year, and 2 years, by deuterium oxide (D2O) dilution. The effect of being born small versus appropriate for gestational age (SGA vs. AGA), and accelerated early growth pattern on FM and FFM accretion was also investigated. Results Newborns (262 total, 150 males) with mean birth weight of 2863 ± 418 g were enrolled. FM percentage (FM%) assessed by D2O in 144, 166, 81, and 115 infants at 12 days, 3.5 months, 1 year, and 2 years respectively, was11.6 ± 6.8, 21.1 ± 7.0, 17.9 ± 8.2 and 22.4 ± 9.5%. Boys had higher FFM at all ages, but FM% was similar in both sexes. Children born SGA had similar FM index (FMI) but a lower FFM index (FFMI) at 2 years compared with those born AGA. Infants with catch-up growth between 0 and 2 years had higher FMI at 2 years compared to those without. Infants in the present study had a lower FM% and FMI till 1 year of age in comparison to previous studies from other countries, but had an increase in adiposity between 1 and 2 years, whereas in previous studies FM% remained stable or declined between 1 and 2 years of age. Conclusion There was an upward inflection in the curve of FM% and FMI between 1 and 2 years of age in the present study, which may represent an early adiposity rebound. Further longitudinal body composition data for Indian infants as well as those of other ethnicities but with low birth weight will clarify whether early accelerated growth pattern contributes to greater accrual of fat rather than lean mass during childhood.