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Table 1 Characteristics of participants by tertile of total soy intakes at baseline1

From: Prospective association of dietary soy and fibre intake with puberty timing: a cohort study among Chinese children

  Total soy intakes at baseline  
  T1
(0–8.2)2
T2
(8.5–39.6)2
T3
(40.1–69.0)2
p3
Girls (n=2152)
N (%) 717 (33.3) 718 (33.4) 717 (33.3)  
 Birth weight (kg) 3.1 (2.7, 3.8) 3.2 (2.9, 3.7) 3.2 (2.6, 3.8) 0.4
 Age at baseline (years) 7.0 (0.8) 7.2 (0.7) 7.1 (0.8) 0.2
 Age at menarche (years, n=1162) 12.5 (0.8) 12.8 (0.7) 13.1 (1.1) 0.03
 Age at Tanner stage B24 (years, n=1748) 9.1 (1.3) 9.3 (1.4) 9.5 (1.2) 0.02
 BMI SDS at baseline (kg/m2) 0.1 (0.7) 0.1 (0.6) 0.2 (0.8) 0.09
 Percent body fatness5at baseline (%) 16.7 (15.2, 19.5) 16.3 (15.0, 18.6) 15.6 (13.7, 18.5) 0.04
 Overweight6 (n (%)) 96 (13.4) 85 (11.8) 80 (11.2) 0.09
 High physical activity (n (%)) 190 (26.5) 202 (28.1) 198 (27.6) 0.1
Parental data at baseline
 High family income7 (n (%)) 151 (21.1) 158 (22.0) 169 (23.6) 0.06
 High paternal educational level8 (n (%)) 144 (20.1) 166 (23.1) 186 (25.9) 0.05
 High maternal educational level8 (n (%)) 127 (17.7) 133 (18.5) 137 (19.1) 0.06
 Smoking in the household (n (%)) 471 (65.8) 408 (56.8) 345 (48.1) 0.03
 Mother’s age at menarche (years) 12.1 (1.0) 12.3 (0.9) 12.4 (1.1) 0.08
Nutritional data9
 Total energy intake (kcal/day) 1594 (236) 1749 (242) 1638 (251) 0.05
 Total soy (soybean and products) (g/day) 6.1 (3.9) 29.2 (8.7) 56.7 (9.8) <0.0001
 Total fibre (g/day) 10.3 (1.3) 10.5 (1.2) 10.6 (1.4) 0.06
  Cereal fibre (g/day) 5.5 (1.0) 5.5 (0.9) 5.6 (1.1) 0.2
  Vegetable and fruit fibre (g/day) 4.2 (1.3) 4.3 (1.1) 4.1 (1.1) 0.1
 Carbohydrate (% of energy) 56.6 (5.0) 57.8 (4.8) 57.2 (4.6) 0.2
 Fat (% of energy) 29.1 (4.6) 27.4 (4.2) 28.7 (4.3) 0.3
 Protein (% of energy) 14.3 (2.0) 14.8 (2.1) 14.1 (1.9) 0.2
  T1
(0–3.2)10
T2
(4.6–48.2)10
T3
(49 1–82.6)10
p3
Boys (n=2629)
N (%) 876 (33.3) 876 (33.3) 877 (33.3)  
 Birth weight (kg) 3.6 (3.0, 3.9) 3.4 (2.7, 4.1) 3.4 (2.5, 4.0) 0.3
 Age at baseline (years) 7.1 (0.8) 7.3 (0.6) 7.3 (0.7) 0.1
 Age at voice break (years, n=829) 13.6 (1.3) 13.9 (1.2) 14.1 (1.2) 0.04
 Age at pubertal stage G24 (years, n=1233) 10.8 (1.3) 11.1 (1.2) 11.4 (1.2) 0.04
 BMI SDS at baseline (kg/m2) 0.1 (0.6) 0.1 (0.8) 0.2 (0.8) 0.1
 Percent body fatness5 at baseline (%) 13.7 (11.0, 17.4) 13.5 (10.1, 17.2) 13.5 (10.6, 17.5) 0.05
 Overweight6 at baseline (n (%)) 122 (13.9) 107 (12.2) 104 (11.9) 0.06
 High physical activity (n (%)) 239 (27.3) 259 (29.6) 255 (29.1) 0.07
Parental data at baseline
 High family income7 (n (%)) 182 (20.8) 183 (20.9) 186 (21.2) 0.06
 Secondary paternal educational level8 (n (%)) 198 (22.6) 209 (23.9) 221 (25.2) 0.04
 Secondary maternal educational level8 (n (%)) 159 (18.2) 163 (18.6) 167 (19.0) 0.03
 Smoking in the household (n (%)) 594 (67.8) 504 (57.5) 458 (52.2) 0.04
 Mother’s age at menarche (years) 12.1 (0.8) 12.3 (0.9) 12.2 (0.9) 0.06
Nutritional data9
 Total energy intake (kcal/day) 1829 (249) 1961 (225) 1790 (229) 0.1
 Total soy (soybean and products) (g/day) 1.6 (1.3) 36.9 (7.6) 57.2 (8.7) <0.0001
 Total fibre (g/day) 9.8 (1.2) 10.1 (1.3) 9.9 (1.2) 0.1
  Cereal fibre (g/day) 4.3 (1.1) 5.2 (1.0) 5.3 (1.1) 0.1
  Vegetable and fruit fibre (g/day) 3.9 (1.2) 3.8 (1.3) 4.1 (1.2) 0.2
 Carbohydrate (% of energy) 58.5 (6.3) 60.8 (6.1) 59.4 (5.9) 0.2
 Fat (% of energy) 27.2 (4.3) 26.1 (4.1) 26.8 (4.2) 0.6
 Protein (% of energy) 14.3 (2.1) 13.1 (2.2) 12.8 (2.1) 0.3
  1. 1 Values are means (SD), medians (Q1, Q3) or frequency
  2. 2 Values are min-max in tertiles in girls
  3. 3 Test for difference between the groups was performed, using ANOVA test for normal distributed continuous variables, Kruskal-Wallis test for not normally distributed continuous variables, and chi-square test for categorical variables
  4. 4 Tanner stage 2 for breast development (girls) or the initiation of gonadal growth (boys)
  5. 5 Calculated according to Slaughter equations [32]
  6. 6 Definition according to the International Obesity Task Force (IOTF) [31]
  7. 7 Average annual income of family at least ≥ 35,000 CNY (Chinese Yuan), which is a moderate level in the general population in South China [41]
  8. 8 School education at least 12 years
  9. 9 Mean values of dietary data at baseline using food frequency questionnaires
  10. 10 Values are min-max in tertiles in boys