Table 5 Multilevel linear regression model of body mass index Z-score using the WHO classification system, in the analytical dataset, El Salvador, 2015/2016

Intercept

0.39 (0.37, 0.42)^a

1.54 (1.44, 1.65)^a

1.36 (1.26, 1.46)^a

1.36 (1.15, 1.56)^a

 Sex (ref.: girls)

0.15 (0.13, 0.16)^a

0.14 (0.13, 0.16)^a

0.14 (0.13,0.16)

 Age

−0.16 (−0.17, −0.15)^a

−0.15 (−0.16, − 0.13)^a

− 0.15 (− 0.16, − 0.13)^a

 Location (ref.: rural)

0.23 (0.20, 0.26)^a

0.22 (0.20, 0.25)^a

 Type (ref.: public)

0.33 (0.29, 0.37)^a

0.32 (0.29, 0.36)^a

 Human development index (ref.: 0.68 or more)

0.12 (0.08, 0.17)^a

 Logarithm of population size

−0.007 (−0.026, 0.012)^b

 Student level variance

1.646

1.635

1.636

1.63

 School/municipal level variance

0.0959

0.0904

0.0640

0.063

Municipal level variance

0.0285

0.0271

0.0130

0.009

Student ICC

92.9%

93.3%

95.5%

95.4%

School ICC

7.03%

6.7%

4.5%

4.5%

Municipal ICC

1.6%

1.5%

0.7%

0.5%

Deviance

3909.49 (Reference)

886.54

1642.89

1680.45

P-value

<  0.001

<  0.001

<  0.001

<  0.001