Table 1. Results from the multivariate regression used for the elaboration of the equation.

	Coefficient	SD	95%CI	p
Last stage	153.4	30.7	[91.4, 215.4]	***
BMI (kg/m2)	58.6	13.3	[31.6, 85.6]	***
Age (years)	−2.7	46.8	[−97.1, 91.7]	0.954
Gendera	320.1	97.1	[124.2, 516.0]	***
Constant variable	−921.2	600.4	[−2131.3, 288.7]	0.132

SD: Standard Deviation; CI: Confidence Interval; ***p<0.001; ^a when gender is boy.