From: Maternal iodine status in a multi-ethnic UK birth cohort: associations with autism spectrum disorder
 |  | Iodine-to-creatinine ratio (cohort split into thirds) | ||
---|---|---|---|---|
 | All participants | lower third | middle third | higher third |
I:Cr (μg/g), median (range) | 83 | 59·5 (< 67) | 83·1 (67 to 105) | 121·9 (> 105) |
N | 6973 | 2325 | 2324 | 2324 |
I:Cr (μg/g), geometric mean (95% CI) | 86·0 (85·0 to 87·2) | 48·6 (48·1 to 49·2) | 83·4 (82·9 to 83·8) | 154·9 (154·9 to 159·3) |
I:Cr (μg/g), median (IQR) | 83·1 (59·3 to 121·0) | 51·5 (42·8 to 59·5) | 83·1 (74·4 to 93·3) | 145·7 (121·0 to 185·9) |
UIC (μg/L), geometric mean (95% CI) | 70·8 (69·6 to 72·1) | 45·9 (44·6 to 47·2) | 69·9 (68·1 to 71·8) | 110·6 (107·7 to 113·7) |
UIC (μg/L), median (IQR) | 76·3 (44·7 to 120·2) | 52·1 (29·0 to 78·1) | 77·4 (47·4 to 111·4) | 117·8 (72·0 to 178·9) |
Age (years), mean (SD) | 27·2 (5·6) | 26·5 (5·5) | 27·3 (5·6) | 27·9 (5·6) |
BMI (kg/M2), mean (SD) | 25·9 (5·5) | 26·5 (5·7) | 25·9 (5·4) | 25·2 (5·1) |
Socio-economic status†| ||||
 Least deprived and most educated | 1313 (21) | 323 (16) | 456 (22) | 534 (26) |
 Employed, not materially deprived | 1299 (21) | 353 (17) | 458 (22) | 488 (23) |
 Employed, no access to money | 966 (16) | 338 (16) | 313 (15) | 315 (15) |
 Receives benefits, not materially deprived | 1671 (27) | 666 (32) | 527 (26) | 478 (23) |
 Most economically deprived | 954 (15) | 378 (19) | 304 (15) | 272 (13) |
Ethnic background, n (%) | ||||
 White British & European | 3020 (43) | 847 (36) | 1061 (46) | 1112 (48) |
 Pakistani | 2951 (43) | 1112 (48) | 951 (41) | 888 (38) |
 Other (Black, Indian, mixed, other) | 964 (14) | 353 (15) | 299 (13) | 312 (14) |
Parity | ||||
 0 | 3196 (46) | 1015 (44) | 1055 (46) | 1126 (49) |
 1 | 1896 (27) | 617 (27) | 640 (27) | 639 (27) |
 2 | 1075 (15) | 376 (16) | 363 (16) | 336 (15) |
 3+ | 806 (12) | 317 (14) | 266 (11) | 223 (10) |
Health and lifestyle in pregnancy | ||||
 Gestational diabetes, n (%) | 525 (8) | 165 (7) | 174 (8) | 186 (8) |
 Pre-pregnancy hypertension, n (%) | 50 (1) | 21 (1) | 17 (1) | 12 (1) |
 Pregnancy-induced hypertension, n (%) | 383 (5) | 128 (5) | 127 (5) | 128 (6) |
 Preeclampsia, n (%) | 181 (3) | 64 (3) | 56 (2) | 61 (3) |
 Drank any alcohol, n (%) | 1323 (19) | 386 (17) | 476 (20) | 461 (20) |
 Smoked, n (%) | 1014 (15) | 321 (14) | 366 (16) | 327 (14) |
 Iodine-containing supplements, n (%) | 1036 (15) | 134 (6) | 279 (12) | 623 (27) |
 Total fish intakea (g/d), mean (SD) | 23·8 (29·3) | 20·9 (28·3) | 25·3 (30·8) | 25·3 (28·4) |
Eat 5 fruit/vegetables per daya, n (%) | ||||
 Always | 441 (18) | 128 (15) | 164 (20) | 149 (19) |
 Sometimes | 1782 (75) | 628 (77) | 595 (73) | 559 (75) |
 Never | 154 (6) | 59 (7) | 52 (6) | 43 (6) |