| Pooled | Early pregnancy | Middle pregnancy | Later pregnancy | ||||
---|---|---|---|---|---|---|---|---|
Iodized salt | Non-iodized salt | Iodized salt | Non-iodized salt | Iodized salt | Non-iodized salt | Iodized salt | Non-iodized salt | |
N | 3436 | 1199 | 1118 | 419 | 1439 | 493 | 879 | 287 |
Age, years | 29 (26–32) | 29 (27–33) | 29 (27–32) | 30 (27–39) | 28 (26–32) | 29 (26–33) | 28 (26–32) | 30 (27–33) |
  ≥ 35 | 450 (13.10) | 191 (15.93)* | 160 (14.39) | 65 (15.25) | 168 (11.67) | 75 (15.21)* | 122 (13.88) | 51 (17.77)* |
Education status n(%) | ||||||||
  ≤ 9 years | 1219 (35.50) | 239 (20.08)* | 318 (28.20) | 54 (13.01)* | 568 (39.50) | 109 (22.29)* | 336 (38.23) | 76 (26.57)* |
 Senior high school and college, | 856 (24.93) | 283 (23.78)* | 310 (27.75) | 95 (22.89)* | 362 (25.17) | 123 (25.15)* | 184 (20.93) | 65 (22.73)* |
 Bachelor’s degree and higher | 1359 (39.57) | 668 (56.13)* | 492 (44.05) | 54 (64.10)* | 508 (35.33) | 257 (52.56)* | 359 (40.84) | 145 (50.70)* |
Occupation status | ||||||||
 Mental | 2724 (79.28) | 979 (81.65) | 873 (78.09) | 331 (79.00) | 1151 (79.99) | 413 (83.77) | 700 (79.64) | 235 (81.88) |
 Physical | 712 (20.75) | 220 (18.35) | 245 (21.91) | 88 (21.00) | 288 (20.01) | 80 (16.23) | 179 (20.36) | 52 (18.12) |
Family income per person last years, yuan | ||||||||
  < 100,000 | 667 (19.46) | 153 (12.88)* | 173 (15.49) | 41 (9.93)* | 300 (20.92) | 71 (14.52)* | 194 (22.12) | 41 (14.43)* |
 100,000–200,000 | 1445 (42.15) | 456 (38.38)* | 471 (42.17) | 158 (38.26)* | 608 (42.40) | 193 (39.47)* | 366 (41.73) | 105 (36.71)* |
  ≥ 200,000 | 1316 (38.39) | 579 (48.74)* | 473 (42.35) | 214 (51.82)* | 526 (36.68) | 225 (46.01)* | 317 (36.15) | 140 (48.95)* |
Former smoker | 81 (2.36) | 37 (3.11) | 27 (2.42) | 14 (3.39) | 38 (2.65) | 15 (3.06) | 16 (1.82) | 8 (2.79) |
Former drinker | 355 (10.37) | 125 (10.56) | 110 (9.87) | 44 (10.68) | 165 (11.50) | 52 (10.68) | 80 (9.15) | 29 (10.18) |
First pregnancy | 1589 (46.25) | 662 (55.21)* | 536 (47.94) | 257 (64.34)* | 638 (44.34) | 254 (51.52) | 415 (47.21) | 151 (52.61) |
Previous thyroid disease | 290 (8.44) | 217 (18.10)* | 104 (9.30) | 95 (22.67)* | 120 (8.34) | 84 (17.04)* | 66 (7.51) | 38 (13.24)* |
Consumed iodine-rich food in the past 3 months | 2747 (79.95) | 923 (76.98)* | 858 (76.74) | 298 (71.12)* | 1175 (81.65) | 388 (78.70) | 714 (81.23) | 237 (82.58) |
Consumed iodized nutritional supplements in the past 3 months | 481 (14.00) | 237 (19.77)* | 145 (12.97) | 64 (15.27)* | 200 (13.90) | 100 (20.28)* | 136 (15.47) | 73 (25.44)* |
UIC, μg/L | 141.00 (83.38–221.35) | 129.53 (74.01–209.08)* | 146.90 (85.80–234.17) | 151.15 (89.80–239.17) | 141.18 (87.44–218.70) | 125.00 (70.56–212.57)* | 129.17 (71.78–203.36) | 111.51 (58.66–168.35)* |
Hypothyroidism | 91 (2.67) | 30 (2.44) | 27 (2.47) | 13 (2.91) | 40 (2.76) | 7 (1.44) | 24 (2.77) | 10 (3.34) |
TPOAb(+) | 439 (12.89) | 253 (20.57)* | 136 (12.47) | 93 (20.85)* | 182 (12.58) | 108 (22.27)* | 121 (13.96) | 52 (17.39) |
TgAb(+) | 305 (8.96) | 140 (11.38) | 123 (11.27) | 70 (15.70) | 122 (8.43) | 49 (10.10) | 60 (6.94) | 21 (7.02) |
TRAb(+) | 505 (14.90) | 201 (16.57) | 152 (13.94) | 77 (17.58) | 223 (15.43) | 84 (17.36) | 130 (15.22) | 40 (13.75) |
TPOAb/TgAb/TRAb(+) | 995 (29.22) | 444 (36.10)* | 305 (27.96) | 160 (35.87)* | 430 (29.22) | 187 (38.56)* | 260 (29.99) | 97 (32.44) |
TPOAb(+)(without previous thyroid disease) | 376 (12.00) | 173 (17.40)* | 107 (10.71) | 53 (15.63)* | 163 (12.24) | 79 (19.95)* | 106 (13.20) | 41 (15.83) |
TgAb(+) (without previous thyroid disease) | 259 (8.27) | 83 (8.35) | 102 (10.21) | 38 (11.21) | 104 (7.81) | 30 (7.58) | 53 (6.61) | 15 (5.79) |
TRAb(+) (without previous thyroid disease) | 467 (14.97) | 166 (16.89) | 143 (14.31) | 60 (17.86) | 202 (15.19) | 73 (18.48) | 122 (15.44) | 33 (13.10) |
TPOAb/TgAb/TRAb(+)(without previous thyroid disease) | 890 (28.40) | 335 (33.70)* | 270 (27.03) | 110 (32.45) | 386 (28.98) | 145 (36.62)* | 234 (29.14) | 80 (30.89) |