Table 2 Comparison in body mass index (BMI) Z-scores between menstruating (post-) and non-menstruating (pre-) adolescent girls by the characteristics of adolescent girls

  < 6

−1.10 ± 0.78

−0.57 ± 0.77

0.19

 6–9

−1.15 ± 1.01

−0.30 ± 0.81

<0.01

  > 9

−0.33 ± 0.88^b

  < 3

−0.05 ± 0.69^b

 3–5

−1.18 ± 1.05

−0.29 ± 0.81

<0.01

  > 5

−1.12 ± 0.91

−0.58 ± 0.84

0.03

 Farming only

−1.13 ± 0.83

−0.37 ± 0.79

<0.01

 Farming plus others

−1.5 ± 0.78

−0.43 ± 0.86

<0.01

 Others

−0.90 ± 1.26

−0.23 ± 0.82

0.01

 Urban

−1.08 ± 1.16

−0.19 ± 0.83

<0.01

 Rural

−1.20 ± 0.97

−0.36 ± 0.81

<0.01

 Northern plateau

−1.22 ± 1.23

−0.40 ± 0.91

<0.01

 Central Shaanxi

−1.15 ± 1.01

−0.30 ± 0.81

<0.01

 Southern region

−1.21 ± 0.77

−0.27 ± 0.71

<0.01