|  | Follow-up at 12 months | Follow-up at 36 months | ||||
---|---|---|---|---|---|---|---|
All (n = 391) n (%) | No (N = 127, 32%) n (%) | Yes (N = 264, 68%) n (%) | p-value | No (N = 201, 51%) n (%) | Yes (N = 190, 49%) n (%) | p-value | |
Mother’s Age upon Enrollment (years) | |||||||
 Age < 20 | 28 (7) | 8 (6.3) | 20 (7.6) | 0.48 | 14 (7) | 14 (7.4) | 0.96 |
 20 ≤ Age < 30 | 223 (57) | 68 (54) | 155 (59) |  | 116 (58) | 107 (56) |  |
 30 ≤ Age < 45 | 140 (36) | 51 (40) | 89 (34) |  | 71 (35) | 69 (36) |  |
Mother’s Ethnicity | |||||||
 Zhuang | 333 (85) | 104 (82) | 229 (87) | 0.28 | 168 (84) | 165 (87) | 0.58 |
 Han | 50 (13) | 21 (17) | 29 (11) |  | 29 (14) | 21 (11) |  |
 Other | 8 (2) | 2 (1.6) | 6 (2.3) |  | 4 (2.0) | 4 (2.1) |  |
Mother’s Education Completed | |||||||
  < High School | 316 (81) | 110 (87) | 206 (78) | 0.04* | 170 (85) | 146 (77) | 0.07 |
 High School | 47 (12) | 9 (7.1) | 38 (14) |  | 19 (9.5) | 28 (15) |  |
 Some University | 18 (4.6) | 3 (2.4) | 15 (5.7) |  | 6 (3.0) | 12 (6.3) |  |
 Missing | 10 (2.6) | 5 (3.9) | 5 (1.9) |  | 6 (3.0) | 4 (2.1) |  |
Father’s Education Completed | |||||||
  < High School | 304 (78) | 103 (81) | 201 (76) | 0.22 | 164 (82) | 140 (74) | 0.02* |
 High School | 57 (15) | 14 (11) | 43 (16) |  | 25 (12) | 32 (17) |  |
 Some University | 20 (5.1) | 4 (3.1) | 16 (6.7) |  | 5 (2.5) | 15 (7.9) |  |
 Missing | 10 (2.6) | 6 (4.7) | 4 (1.5) |  | 7 (3.5) | 3 (1.6) |  |
Mother’s Occupation | |||||||
 Farmer | 298 (76) | 108 (85) | 190 (72) | 0.015* | 158 (79) | 140 (74) | 0.50 |
 Workera | 31 (7.9) | 6 (4.7) | 25 (9.5) |  | 12 (6.0) | 19 (10) |  |
 Unemployed | 42 (11) | 9 (7.1) | 33 (13) |  | 21 (10) | 21 (11) |  |
 Other | 13 (3.3) | 1 (< 1) | 12 (4.5) |  | 7 (3.5) | 6 (3.2) |  |
 Missing | 7 (1.8) | 3 (2.4) | 4 (1.5) |  | 3 (1.5) | 4 (2.1) |  |
Father’s Occupation | |||||||
 Farmer | 289 (74) | 101 (80) | 188 (71) | 0.08 | 155 (77) | 134 (71) | 0.046* |
 Workera | 53 (14) | 13 (10) | 40 (15) |  | 18 (9.0) | 35 (18) |  |
 Unemployed | 23 (5.9) | 5 (3.9) | 18 (6.8) |  | 14 (7.0) | 9 (4.7) |  |
 Other | 17 (4.3) | 2 (1.2) | 15 (5.7) |  | 8 (4.0) | 9 (4.7) |  |
 Missing | 9 (2.3) | 6 (4.7) | 3 (1.1) |  | 6 (3.0) | 3 (1.6) |  |
Household Monthly Income (RMB)b | |||||||
 Income < 2000 | 230 (59) | 68 (54) | 162 (61) | 0.26 | 114 (57) | 116 (61) | 0.72 |
 2000 ≤ Income < 5000 | 107 (27) | 39 (31) | 68 (26) |  | 58 (29) | 49 (26) |  |
 Income ≥5000 | 19 (4.9) | 8 (6.3) | 11 (4.2) |  | 10 (5.0) | 9 (4.7) |  |
 Missing | 35 (9.0) | 12 (9.4) | 23 (8.7) |  | 19 (9.5) | 16 (8.4) |  |
Maternal Pre-Pregnancy BMI (kg/m2)c | |||||||
 Underweight | 90 (23) | 21 (17) | 69 (26) | 0.07 | 39 (19) | 51 (27) | 0.33 |
 Normal Weight | 231 (59) | 82 (65) | 149 (56) |  | 126 (63) | 105 (55) |  |
 Overweight | 60 (15) | 23 (18) | 37 (14) |  | 30 (15) | 30 (16) |  |
 Obese | 9 (2.3) | 1 (< 1) | 8 (3.3) |  | 5 (2.5) | 4 (2.1) |  |
 Missing | 1 (< 1) | 0 (0) | 1 (< 1) |  | 1 (< 1) | 0 (0) |  |
Maternal Smoking During Pregnancy | |||||||
 No | 377 (96) | 117 (92) | 260 (98) | 0.003** | 191 (95) | 186 (98) | 0.37 |
 Yes | 5 (1.3) | 5 (3.9) | 0 (0) |  | 4 (2.0) | 1 (< 1) |  |
 Missing | 9 (2.3) | 5 (3.9) | 4 (1.6) |  | 6 (3.0) | 3 (1.6) |  |
2nd-Hand Smoke Exposure During Pregnancy | |||||||
 No | 214 (55) | 65 (51) | 149 (56) | 0.41 | 100 (50) | 114 (60) | 0.06 |
 Yes | 163 (42) | 56 (44) | 107 (41) |  | 92 (46) | 71 (37) |  |
 Missing | 14 (3.6) | 6 (4.7) | 8 (3.3) |  | 9 (4.5) | 5 (2.6) |  |
Alcohol During Pregnancy | |||||||
 No | 379 (97) | 121 (95) | 258 (98) | 1.0 | 196 (98) | 183 (96) | 0.36 |
 Yes | 4 (1.0) | 1 (< 1) | 3 (1.1) |  | 1 (< 1) | 3 (1.6) |  |
 Missing | 8 (2.0) | 5 (3.9) | 3 (1.1) |  | 4 (2.0) | 4 (2.1) |  |
Anemia During Pregnancy | |||||||
 No | 377 (96) | 123 (97) | 254 (96) | 0.56 | 193 (96) | 184 (97) | 1.0 |
 Yes | 13 (3.3) | 3 (2.4) | 10 (3.8) |  | 7 (3.5) | 6 (3.2) |  |
 Missing | 1 (< 1) | 1 (< 1) | 0 (0) |  | 1 (< 1) | 0 (0) |  |
Primipara | |||||||
 No | 185 (47) | 66 (52) | 119 (45) | 0.20 | 97 (48) | 88 (46) | 0.64 |
 Yes | 190 (49) | 56 (44) | 134 (51) |  | 95 (47) | 95 (50) |  |
 Missing | 16 (4.1) | 5 (3.9) | 11 (4.2) |  | 9 (4.5) | 7 (3.7) |  |
Maternal Rice Consumption | |||||||
  < Daily | 47 (12) | 12 (9.4) | 35 (13) | 0.26 | 23 (11) | 24 (13) | 0.72 |
  ≥ Daily | 323 (83) | 109 (86) | 214 (81) |  | 167 (83) | 156 (82) |  |
 Missing | 21 (5.4) | 6 (4.7) | 15 (5.7) |  | 11 (5.5) | 10 (5.3) |  |
Maternal Fish Consumption (servings/week) | |||||||
 0 servings/week | 169 (43) | 60 (47) | 109 (41) | 0.33 | 87 (43) | 82 (43) | 0.87 |
 0 < servings/week < 2 | 178 (46) | 51 (40) | 127 (48) |  | 93 (46) | 85 (45) |  |
  ≥ 2 servings/week | 44 (11) | 16 (13) | 28 (11) |  | 21 (10) | 23 (12) |  |
Cesarean Birth | |||||||
 No | 285 (73) | 91 (72) | 194 (27) | 0.70 | 138 (69) | 147 (77) | 0.05* |
 Yes | 106 (27) | 36 (28) | 70 (73) |  | 63 (31) | 43 (23) |  |
Child Sex | |||||||
 Male | 198 (51) | 53 (42) | 140 (53) | 0.04* | 94 (47) | 104 (55) | 0.12 |
 Female | 193 (49) | 74 (58) | 124 (47) |  | 107 (53) | 86 (45) |  |
Gestational Age (weeks) | |||||||
 37 ≤ Gestational Age < 39 | 151 (39) | 55 (43) | 96 (36) | 0.22 | 81 (40) | 70 (37) | 0.54 |
 39 ≤ Gestational Age < 41 | 215 (55) | 68 (54) | 147 (56) |  | 110 (55) | 105 (55) |  |
 Gestational Age ≥ 41 | 22 (5.6) | 4 (3.2) | 18 (6.8) |  | 9 (4.5) | 13 (6.8) |  |
 Missing | 3 (< 1) | 0 (0) | 3 (1.1) |  | 1 (< 1) | 2 (1.1) |  |
Birth weight-for-gestational age z-score (centile)d | |||||||
 Value < 10th | 45 (12) | 13 (10) | 32 (12) | 0.41 | 20 (10) | 25 (13) | 0.47 |
 10th ≤ Value <90th | 327 (84) | 111 (87) | 216 (81) |  | 173 (86) | 154 (81) |  |
 Value ≥90th | 16 (4.1) | 3 (2.4) | 13 (4.9) |  | 7 (3.5) | 9 (4.7) |  |
 Missing | 3 (< 1) | 0 (0) | 3 (1.1) |  | 1 (< 1) | 2 (1.1) |  |
Questionnaire Responses at 12 or 36 Months | |||||||
 Primary Caregiver | |||||||
  Mother | NA | NA | 208 (79) | NA | NA | 115 (61) | NA |
  Father | NA | NA | 32 (12) |  | NA | 23 (12) |  |
  Grandparent | NA | NA | 24 (9.1) |  | NA | 52 (27) |  |
  Other relative | NA | NA | 0 (0) |  | NA | 0 (0) |  |
 Mother or Father is a Migrant Worker | |||||||
  No | NA | NA | 251 (95) | NA | NA | 149 (78) | NA |
  Yes | NA | NA | 9 (3.5) |  | NA | 41 (22) |  |
  Missing | NA | NA | 4 (1.5) |  |  | 0 (0) |  |
 Older Child in the Household | |||||||
  No | NA | NA | 160 (61) | NA | NA | 102 (54) | NA |
  Yes | NA | NA | 104 (39) |  | NA | 86 (45) |  |
  Missing | NA | NA | 0 (0) |  | NA | 2 (1.1) |  |
 Breastfeeding Duration > Median (8.5 months)e | |||||||
  No | NA | NA | 127 (48) | NA | NA | 89 (47) | NA |
  Yes | NA | NA | 136 (52) |  | NA | 100 (53) |  |
  Missing | NA | NA | 1 (< 1) |  | NA | 1 (< 1) |  |