Table 1. Multivariate analysis for plasma phosphate and calcium concentration and calcium balance.

		β-coefficient	r-partial	P-value
Calcemia (r2 0.38)
	Amino acid intake	0.038	0.29	<0.001
	Postnatal age	0.060	0.22	<0.001
	Phosphorus intake	-0.002	-0.18	<0.001
	Gestational age	0.015	0.14	<0.001
	Caloric Intake	-0.001	-0.07	0.04
Phosphatemia (r2 0.24)
	Amino acid intake	-0.090	-0.40	<0.001
	Phosphorus intake	0.004	0.20	<0.001
	Caloric Intake	0.002	0.14	0.002
	Postnatal age	-0.069	-0.13	0.006
Calcium balance (r2 0.37)
	Calcium intake	0.28	0.53	<0.001
	Postnatal age	-13.5	-0.51	<0.001
	Amino acid intake	-1.63	-0.28	<0.001
	Diuresis	-0.90	-0.14	0.002
	Phosphorus intake	0.05	0.10	0.03