Skip to main content

Table 1 Characteristics of study participants by sex (Japan, 2001–2008)

From: Lifestyle factors associated with underweight among Japanese adolescents: a cross-sectional study

  Boys (N = 1211) Girls (N = 1139) P valuea
Age (years) 12.0 (12.0, 13.0) 12.0 (12.0, 13.0) 0.822
Bitrhweight (g), n (%)
  < 2500 77 (6.4) 85 (7.5) 0.291
  ≥ 2500 1134 (93.6) 1054 (92.5)  
Height (cm) 155.6 (149.2, 161.0) 153.3 (149.4, 157.2) <0.001
Weight (kg) 44.3 (38.8, 50.8) 43.5 (38.9, 48.1) 0.007
BMI (kg/m2) 18.2 (16.8, 20.0) 18.3 (16.9, 20.0) 0.389
BMI-SDS 0.25(−0.35, 0.89) 0.15 (−0.44, 0.75) 0.002
Physique, n (%)
 Underweight 99 (8.2) 127 (11.2) 0.005
 Normal weight 933 (77.0) 882 (77.4)  
 Overweight/obesity 179 (14.8) 130 (11.4)  
Exercise, n (%)
 Daily 1003 (82.8) 668 (58.7) <0.001
 Sometimes 94 (7.8) 157 (13.8)  
 None 114 (9.4) 314 (27.6)  
Skipping breakfast, n (%)
 Yes 58 (4.8) 84 (7.4) 0.009
 No 1153 (95.2) 1055 (92.6)  
Snacking after dinner, n (%)
 Always or often 735 (60.7) 659 (57.9) 0.162
 Seldom or none 476 (39.3) 480 (42.1) 0.015
Snacking while watching television or reading books, n (%)
 Yes 482 (39.8) 510 (44.8) 0.015
 No 729 (60.2) 629 (55.2)  
Eating slowly, n (%)
 Yes 207 (17.1) 279 (24.5) <0.001
 No 1004 (82.9) 860 (75.5)  
  1. BMI body mass index, BMI-SDS body mass index standard deviation score
  2. Except where indicated n (%), values are expressed as median (25, 75th percentile)
  3. aWilcoxon rank-sum test or chi-square test