106 - Longitudinal changes in body composition in preterm infants with systemic steroid exposure

Poster Number: 106
Publication Number: 106.113

Background: Fat-free mass (FFM) deposition is associated with improved neurodevelopment and brain growth in very preterm (VP, < 32 weeks’ gestational age [GA]) infants. VP infants may receive systemic corticosteroids (steroids) during the neonatal intensive care unit (NICU) hospitalization to prevent or treat bronchopulmonary dysplasia (BPD) or adrenal insufficiency.

Objective: To compare longitudinal body composition measurements (FFM and fat mass (FM)) in VP infants with and without exposure to steroids during hospitalization.

Design/Methods: Prospective study of 36 VP infants with birth weight (BW) < 1500 g and admitted within 48 hours of life. Collected data: anthropometrics, steroid history, BPD, and infant and maternal demographics. Fenton or World Health Organization growth curves were used to determine z-scores. Body composition was measured using bioelectrical impedance analysis (BIA) within 72 hours preceding discharge and at 4-months corrected age (CA) and 8-months CA. To improve precision, we repeated measurements four times per infant and used the median BIA resistance value in the Kushner equation to determine FFM for each infant. FM was calculated by subtracting FFM from the infant’s weight. Z-scores were then calculated based on 2019 Norris reference values obtained with air displacement plethysmography. 36 infants had BIA data at discharge and 4-months CA and 27 infants had BIA data at discharge, 4- and 8-months CA. The FM, FFM, %FM z-scores in steroid-exposed (SE) and non-steroid-exposed (NSE) cohorts were compared using Mann-Whitney U tests.

Results: Overall mean BW ± SD was 1017 ± 328 g and mean GA 27.9 ± 2.5 weeks (Table 1). 11 infants (31%) received steroids. There was no significant difference noted in median z-scores for FFM (SE .362 vs. NSE .124, p=.685), FM (SE .405 vs. NSE -2.32, p=.142) or %FM (SE -.041 vs. NSE -2.34, p=.396) between SE and NSE infants at NICU discharge nor in median z-scores for FFM (SE .488 vs. NSE -.146, p=.220), FM (SE -1.72 vs. NSE -.803, p=.477) or %FM (SE -2.17 vs. NSE -.733, p=.183) at 4-months CA (Figure 1). Data from 27 infants (9 SE) with data from all 3 visits suggested a difference in the longitudinal %FM pattern between the steroid and non-steroid exposed cohorts (Figure 2) with SE decreasing %FM and NSE increasing %FM between discharge and 4-months CA with no apparent change noted from 4-months to 8-months CA.

Conclusion(s): We found no evidence that SE infants had altered body composition at or after discharge compared to NSE VP infants. Future analyses will adjust for potentially confounding factors such as neonatal illnesses and GA at birth.