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Table 1 Characteristics of participants stratified by sex and birthweight for gestational age categories

From: Infant weight gain and DXA-measured adolescent adiposity: data from the Japan Kids Body-composition Study

  Boys Girls
Birthweight for gestational age categories Birthweight for gestational age categories
SGA (N = 10) AGA (N = 151) LGA (N = 44) p value SGA (N = 10) AGA (N = 166) LGA (N = 42) p value
Maternal characteristics at pregnancy
 Age, years 26.6 ± 1.4 29.7 ± 0.4 29.3 ± 0.7 0.11 28.1 ± 1.6 28.5 ± 0.4 30.6 ± 0.8 0.05
 Gestational age, weeks 39.9 ± 0.3 39.0 ± 0.1 38.9 ± 0.2 0.02 38.5 ± 0.3 39.0 ± 0.1 39.1 ± 0.2 0.26
Characteristics of the child at birth
 Length z-score − 0.84 ± 0.24 0.06 ± 0.06 0.79 ± 0.12 < 0.01 − 1.5 ± 0.2 0.1 ± 0.1 0.9 ± 0.1 < 0.01
 Weight z-score − 1.36 ± 0.20 − 0.02 ± 0.05 1.57 ± 0.09 < 0.01 − 1.9 ± 0.2 − 0.2 ± 0.0 1.2 ± 0.1 < 0.01
Characteristics of the child at age 1.5 years
 Height z-score − 0.23 ± 0.28 0.36 ± 0.07 0.87 ± 0.13 < 0.01 − 0.1 ± 0.3 0.1 ± 0.1 0.7 ± 0.2 < 0.01
 Weight z-score − 0.37 ± 0.28 0.25 ± 0.07 1.09 ± 0.13 < 0.01 − 0.2 ± 0.3 0.2 ± 0.1 1.1 ± 0.1 < 0.01
Change in weight z-score from 0 to 1.5 years 0.99 ± 0.31 0.27 ± 0.08 − 0.48 ± 0.15 < 0.01 1.7 ± 0.3 0.4 ± 0.1 0.0 ± 0.2 < 0.01
Characteristics of the child at adolescence
 Height z-score 0.06 ± 0.28 0.29 ± 0.07 0.50 ± 0.13 0.22 − 0.7 ± 0.3 − 0.1 ± 0.1 0.4 ± 0.1 < 0.01
 Weight z-score − 0.32 ± 0.31 0.20 ± 0.08 0.35 ± 0.15 0.14 0.2 ± 0.3 − 0.1 ± 0.1 0.4 ± 0.1 < 0.01
 BMI, kg/m2 17.7 ± 0.9 19.2 ± 0.2 19.5 ± 0.4 0.22 21.5 ± 0.8 19.4 ± 0.2 20.4 ± 0.4 0.01
 WC, cm 64.9 ± 2.5 68.8 ± 0.6 69.5 ± 1.2 0.26 70.4 ± 2.0 67.9 ± 0.5 70.6 ± 1.0 0.03
 Fat mass index, kg/m2 2.2 ± 0.5 3.0 ± 0.1 2.9 ± 0.2 0.25 5.7 ± 0.5 4.5 ± 0.1 5.1 ± 0.2 0.01
 Body fat percentage, % 12.4 ± 1.6 15.1 ± 0.4 14.4 ± 0.8 0.23 25.2 ± 1.5 22.8 ± 0.4 24.2 ± 0.7 0.10
 Lean mass index, kg/m2 15.1 ± 0.5 15.8 ± 0.1 16.2 ± 0.2 0.10 15 ± 0.4 14.5 ± 0.1 14.9 ± 0 0.04
 Overweight, N (%) 0 (0.0) 22 (14.6) 5 (11.4) 0.59 2 (20.0) 12 (7.2) 6 (14.3) 0.12
 Sedentary behavior, N (%)
  < 2 h 7 (70.0) 100 (66.2) 21 (47.7) 0.10 3 (30.0) 93 (56.0) 23 (54.8) 0.33
  2–3 h 1 (10.0) 28 (18.6) 16 (36.4)   3 (30.0) 47 (28.3) 13 (31.0)  
  ≥ 3 h 2 (20.0) 23 (15.2) 7 (15.9)   4 (40.0) 26 (15.7) 6 (14.2)  
 Pubic hair appearance, N (%)
  Age < 12 years 3 (30.0) 42 (27.8) 11 (25.0) 0.92 9 (90.0) 108 (65.1) 28 (66.7) 0.31
  Age ≥ 12 years 7 (70.0) 109 (72.2) 33 (75.0)   1 (10.0) 58 (34.9) 14 (33.3)  
RWG from 0 to 1.5 years, N (%) 7 (70.0) 51 (33.8) 10 (22.7) 0.02 9 (90.0) 65 (39.2) 10 (23.8) < 0.01
  1. Data are expressed as mean ± standard deviation or number (proportion in %)
  2. N number, SGA small for gestational age, AGA appropriate for gestational age, LGA large for gestational age, BMI body mass index, WC waist circumference, RWG rapid weight gain