# Table 3 Comparisons of characteristics between the normal weight and underweight groups in girls (Japan, 2001–2008)

Normal weight (n = 882) Underweight (n = 127) P valuea
Age (years) 12.0 (12.0, 13.0) 12.0 (12.0, 13.0) 0.017
Birthweight (g), n (%)
< 2500 77 (8.7) 6 (4.7) 0.125
≥ 2500 805 (91.3) 121 (95.3)
Height (cm) 153.4 (149.6, 157.1) 151.3 (147.1, 155.5) <0.001
Weight (kg) 43.5 (39.7, 46.9) 34.7 (32.3, 37.2) <0.001
Body mass index (kg/m2) 18.3 (17.2, 19.5) 15.3 (14.7, 15.5) <0.001
Exercise, n (%)
Daily 547 (62.0) 65 (51.2) 0.033
Sometimes 115 (13.0) 17 (13.4)
None 220 (24.9) 45 (35.4)
Skipping breakfast, n (%)
Yes 63 (7.1) 7 (5.5) 0.499
No 819 (92.9) 120 (94.5)
Snacking after dinner, n (%)
Always or often 509 (57.7) 76 (59.8) 0.649
Seldom or none 373 (42.3) 51 (40.2)
Snacking while watching television or reading books, n (%)
Yes 397 (45.0) 58 (45.7) 0.889
No 485 (55.0) 69 (54.3)
Eating slowly, n (%)
Yes 203 (23.0) 56 (44.1) <0.001
No 679 (77.0) 71 (55.9)
1. Except where indicated n (%), values are expressed as median (25, 75th percentile)
2. aWilcoxon rank-sum test or chi-square test