TABLE 4.

Associations between weight gain trajectories and body composition at 2 months and 6 months

	2 months (n = 103)					6 months (n = 92)
	%FM	FM	FMI	LM	LMI	%FM	FM	FMI	LM	LMI
Weight gain trajectory
NICU	¥	¥	¥	3.3%*	¥	¥	¥	¥	¥	¥
Level‐II hospital	6.5%*	11.9%**	7.9%*	10.8%**	¥	¥	¥	¥	4.6%*	¥
Home	32.6%**	49.8%**	46.3%**	24.6%**	6.0%*	24.6%**	46.8%**	36.5%**	31.8%**	8.6%*

Note: The values represent the variance (R²) in body composition explained by the weight gain trajectories (Z‐score), computed as the change in R² by adding the timeframe specific weight gain trajectory indicators (intercept and/or slope) to the linear regression model. Covariates included gestational age at birth, birth weight Z‐score, sex, corrected age at body composition measurement, days on parenteral nutrition during NICU stay, days on invasive respiratory support, socio‐economic status, and breast milk at two months CA (any/no). ¥ R² < 3% and P‐value >.05, * p‐value <.05, **p‐value <.001.

Abbreviations: %FM, percentage fat mass relative to weight; FM, absolute fat mass in kilograms; FMI, fat mass index (FM/length(m)²); LM, absolute lean mass in kilograms; LMI, lean mass index (LM/length(m)²); NICU, neonatal intensive care unit.