Steady Growth in Early Infancy Is Associated with Greater Anthropometry in Indian Children Born Low Birth Weight at Term

BACKGROUND: Patterns of early growth are associated with later body composition and risk of adult noncommunicable disease but information from low-income countries is limited. OBJECTIVES: The aim of this study was to investigate early growth trajectories and later anthropometric and bone density outcomes among children born term low birth weight (LBW: 1.8–2.5 kg). METHODS: We used data from 902 children from the Delhi Infant Vitamin D Supplementation study of LBW term infants (which collected monthly anthropometry from birth to 6 mo) and who had height, weight, midupper arm circumference (MUAC), midupper arm muscle circumference (MUAMC), subscapular and triceps skinfold thicknesses, tibia and radius bone density measured at age 4–6 y. We investigated how growth in the first 6 mo of life, modeled using the SuperImposition by Translation and Rotation (SITAR) growth curve model, was related to these outcomes. SITAR summarizes each infant's weight and length trajectory in terms of a population mean curve and child-specific growth parameters: size, timing, and intensity. These were included as explanatory variables in linear regression models for the childhood outcomes. RESULTS: Considering the infant weight and length SITAR parameters jointly, childhood weight was strongly associated with infant length timing [estimated regression coefficient β = 0.25 (95% CI: 0.10, 0.39)] and with weight size, timing, and intensity [β = 9.01 (6.75, 11.27), β = −0.25 (−0.43, −0.07), β = 5.03 (3.22, 6.84), respectively]. Childhood height was associated only with the length parameters [β = 0.97 (0.71, 1.23), β = −0.43 (−0.77, −0.09), β = 11.68 (8.60, 14.75), respectively]; childhood MUAC, MUAMC, and skinfolds with all parameters; and bone density with none. Overall, delayed and sustained growth in infant weight and length resulted in higher values of all outcomes except bone density, with the period up to 15 wk of age appearing critical for setting childhood anthropometry in this population. CONCLUSIONS: The explanation for the effects of delayed growth and length of the period in which trajectories are set is unclear; however, sustained and delayed growth in early infancy appears to be beneficial for these LBW children at least in the short-term. The trial was registered at clinicaltrials.gov as BT/PR7489/PID/20/285/2006.