Race as social determinant of growth and body composition among infants born very preterm.

Objective: Racism leads to disparities in health outcomes. Our objective was to determine if black race was independently associated with differences in fat accretion at discharge in a large cohort of very preterm infants (32 weeks of gestation or less).

Methods: De-identified demographic, anthropometric and body composition data were collected from seven neonatal units around the United States. Weight, length, and head circumference z-scores at birth and at the time of body composition assessment or hospital discharge were calculated.

Results: The median gestational age and birthweight for this cohort (n = 888) were 29 weeks [IQR, 27-30] and 1167 g [SD, 354], respectively. The study population included 53% black preterm infants. Birthweight was lower in black preterm infants compared with white infants (1112 ± 334 g vs. 1228 ± 366 g; p < 0.0001). After adjusting for birthweight, gestational age, and birthweight-for-age z-score, black preterm infants had more weight gain (adjusted mean difference: 0.5 g/kg/day; p = 0.03) but not higher BF% z-scores at hospital discharge (adjusted mean: 1.2 vs. 1.3; p = 0.14) than white infants.

Conclusions: After adjusting for covariates, black race was associated with higher weight gain velocity but not higher BF% z-scores.

Impact: This study presents findings from a large-scale multicenter cohort. Racial differences were observed in birth weight and the rate of weight gain; however, these differences were not associated with dissimilarities in body composition outcomes. Understanding nutrition and growth outcomes across racial groups is necessary to combat racial disparities in the neonatal intensive care unit (NICU).