Table 1.
Characteristics of participants by group of diet qualitya at baseline
| Diet quality according to CCDI score | p | |||
|---|---|---|---|---|
| Lower (56.2–82.3)b | Moderate (82.9–105.6)b | Higher (106.2–136.3)b | ||
| Girls (n = 1752) | ||||
| N (%) | 584 (33.3) | 584 (33.3) | 584 (33.3) | |
| Birth weight (kg) | 3.1 (2.8, 3.8) | 3.3 (2.9, 3.7) | 3.2 (2.7, 3.8) | 0.3 |
| Age at baseline (years) | 7.1 (0.8) | 7.3 (0.8) | 7.2 (0.9) | 0.1 |
| Age at menarche (years, n = 976) | 12.6 (0.8) | 12.8 (0.9)* | 13.2 (1.0)#※ | 0.02 |
| Age at Tanner stage B2d (years, n = 1550) | 9.0 (1.4) | 9.3 (1.5)* | 9.6 (1.2)#※ | 0.01 |
| BMI SDS at baseline (kg/m2) | 0.3 (0.8) | 0.2 (0.7) | 0.2 (0.8) | 0.1 |
| Percent body fatnesse at baseline (%) | 16.9 (15.3, 19.6) | 16.5 (15.1, 18.4)* | 15.7 (13.6, 18.8)#※ | 0.04 |
| Overweightf (n (%)) | 77 (13.2) | 66 (11.3) | 64 (11.0) | 0.1 |
| High physical activity (n (%)) | 153 (26.2) | 168 (28.8) | 166 (28.4) | 0.06 |
| Duration of breastfeeding (weeks) | 16.8 (5.9) | 15.7 (5.3) | 18.6 (6.3) | 0.07 |
| Parental data at baseline | ||||
| High family incomeg (n (%)) | 122 (20.8) | 130 (22.3) | 137 (23.5) | 0.06 |
| High paternal educational levelh (n (%)) | 117 (20.0) | 137 (23.5)* | 151 (25.9)#※ | 0.04 |
| High maternal educational levelh (n (%)) | 105 (18.0) | 108 (18.5) | 111 (19.0) | 0.07 |
| Smoking in the household (n (%)) | 386 (66.1) | 328 (56.2)* | 284 (48.6)#※ | 0.02 |
| Mother’s age at menarche (years) | 12.0 (0.9) | 12.3 (0.8)* | 12.5 (1.1)#※ | 0.05 |
| Nutritional datai | ||||
| Total energy intake (kcal/d) | 1401 (228) | 1626 (237) | 1531 (232) | 0.06 |
| Carbohydrates (% of energy) | 53.1 (5.2) | 58.8 (4.3)* | 57.3 (4.5)#※ | 0.04 |
| Fat (% of energy) | 32.3 (4.9) | 26.1 (4.3)* | 29.0 (4.4)#※ | 0.02 |
| Protein (% of energy) | 14.6 (2.2) | 15.1 (2.1)* | 13.7 (1.9)#※ | 0.03 |
| Lower (46.1–77.5)j | Moderate (78.2–101.7)j | Higher (102.3–131.5)j | p | |
|---|---|---|---|---|
| Boys | ||||
| N (%) | 743 (33.3) | 744 (33.3) | 744 (33.3) | |
| Birth weight (kg) | 3.6 (3.1, 3.9) | 3.3 (2.8, 4.1) | 3.4 (2.8, 3.9) | 0.1 |
| Age at baseline (years) | 7.0 (0.9) | 7.3 (0.7) | 7.1 (0.8) | 0.1 |
| Age at voice break (years, n = 612) | 13.5 (1.2) | 13.8 (1.3)* | 14.1 (1.1)#※ | 0.03 |
| Age at pubertal stage G2d (years, n = 1121) | 10.9 (1.2) | 11.2 (1.4) | 11.4 (1.0) | 0.05 |
| BMI SDS at baseline (kg/m2) | 0.3 (0.8) | 0.3 (0.6) | 0.2 (0.7) | 0.3 |
| Percent body fatnesse at baseline (%) | 13.9 (11.4, 17.5) | 13.6 (10.2, 17.3)* | 13.5 (11.0, 17.8)#※ | 0.04 |
| Overweightf at baseline (n (%)) | 104 (14.0) | 89 (12.0) | 83 (11.2) | 0.09 |
| High physical activity (n (%)) | 197 (26.5) | 219 (29.4) | 215 (28.9) | 0.06 |
| Duration of breastfeeding (weeks) | 19.2 (5.2) | 20.5 (5.8) | 20.6 (6.1) | 0.08 |
| Parental data at baseline | ||||
| High family incomeg (n (%)) | 152 (20.5) | 153 (20.6) | 158 (21.2) | 0.07 |
| High paternal educational levelh (n (%)) | 166 (22.3) | 176 (23.6)* | 187 (25.1)#※ | 0.03 |
| High maternal educational levelh (n (%)) | 135 (18.2) | 136 (18.3) | 141 (19.0) | 0.05 |
| Smoking in the household (n (%)) | 499 (67.2) | 425 (57.1)* | 391 (52.6)#※ | 0.03 |
| Mother’s age at menarche (years) | 12.2 (0.7) | 12.4 (0.9) | 12.3 (0.8) | 0.08 |
| Nutritional datai | ||||
| Total energy intake (kcal/d) | 1910 (237) | 1816 (218) | 1772 (223) | 0.06 |
| Carbohydrates (% of energy) | 58.7 (6.5) | 59.8 (6.2)* | 61.0 (5.8)#※ | 0.03 |
| Fat (% of energy) | 26.4 (4.6) | 27.3 (4.2) | 26.5 (4.4) | 0.05 |
| Protein (% of energy) | 14.9 (2.4) | 12.9 (2.2)* | 12.5 (2.0)#※ | 0.04 |
aValues are means (SD), medians (Q1, Q3) or frequency; CCDI, Chinese Children Dietary Index, based on dietary data at baseline
bValues are min–max in tertiles in girls
cTest for difference between the groups was performed, using ANOVA test for normally distributed continuous variables, Kruskal–Wallis test for not normally distributed continuous variables, followed by Student–Newman–Keuls tests or Dunn’s post hoc tests, and Chi square test for categorical variables. *P < 0.05 between lower and moderate diet quality group, #P < 0.05 between moderate and higher diet quality group < 0.05, ※P < 0.05 between lower and higher diet quality group
dTanner stage 2 for breast development (girls) or the initiation of gonadal growth (boys)
eCalculated according to Slaughter et al. [43]
fDefinition according to the International Obesity Task Force (IOTF) [53]
gAverage annual income of family at least ≥ 35,000 CNY (Chinese Yuan), which is moderate level among the general population in South China
hSchool education at least 12 years
iMean values of dietary data at baseline using food frequency questionnaires
jValues are min–max in tertiles in boys