Table 3 Regression coefficients from stratified multiple linear regression analysis associated with change in BMI z-score from 2014 to 2016 for children who were underweight, normal weight, and overweight in 2014, respectively

Stratified to underweight (n = 78)

 Constant

−0.23 (− 0.97, 0.52)

0.55

 Age in months^a

−0.011 (− 0.022, 0.000)

−0.19

0.04

 Boys, n (%)^b

0.17 (−0.18, 0.53)

0.09

0.38

 Baseline BMI z-score^a,c

−0.82 (−1.08, − 0.56)

−0.57

< 0.001

Stratified to normal weight (n = 521)

 Constant

−0.25 (− 0.41, − 0.09)

0.002

 Age in months^a

0.006 (0.003, 0.009)

0.18

< 0.001

 Boys, n (%)^b

0.06 (−0.04, 0.16)

0.05

0.25

 Baseline BMI z-score^a,c

−0.13 (− 0.22, − 0.04)

−0.12

0.01

Stratified to overweight (n = 77)

 Constant

−0.25 (− 0.76, 0.26)

0.34

 Age in months^a

0.013 (0.007, 0.018)

0.46

< 0.001

 Boys, n (%)^b

−0.12, (− 0.34, 0.10)

− 0.11

0.27

 Baseline BMI z-score^a,c

−0.31 (− 0.54, − 0.09)

−0.27

0.01