Table 2.
Iodine intake, median and range (5th percentile, 95th percentile) by maternal characteristics.
| Iodine from food | Total iodine | |||||
|---|---|---|---|---|---|---|
| n (%) | Median (P5, P95) | p-Value * | Median (P5, P95) | p-Value * | ||
| μg/day | μg/day | |||||
| All | 61,904 | 141 (65, 280) | 166 (71, 369) | |||
| Maternal age | ||||||
| <25 years | 6880 (11.1) | 141 (61, 305) | 0.406 | 164 (65, 389) | 0.207 | |
| 25–29 years | 20,926 (38.3) | 141 (64, 282) | 167 (70, 373) | |||
| 30–34 years | 23,554 (38.0) | 141 (66, 274) | 165 (73, 362) | |||
| ≥35 years | 10,544 (17.0) | 141 (67, 275) | 166 (74, 367) | |||
| Parity | ||||||
| Nulliparous | 32,053 (51.8) | 139 (64, 280) | <0.001 | 169 (71, 381) | ||
| Primiparous | 19,262 (31.1) | 141 (65, 279) | 162 (70, 357) | <0.001 | ||
| Multiparous | 10,589 (17.1) | 147 (67, 284) | 164 (72, 356) | |||
| Maternal education | ||||||
| ≤12 years | 19,809 (32.0) | 140 (60, 295) | 0.607 | 163 (65, 372) | <0.001 | |
| 13–16 years | 26,612 (43.0) | 141 (66, 276) | 167 (73, 369) | |||
| ≥17 years | 15,484 (25.0) | 141 (70, 267) | 167 (76, 366) | |||
| Marital status | ||||||
| Married/cohabiting | 59,726 (96.5) | 141 (65, 279) | 0.083 | 166 (71, 368) | 0.246 | |
| Not married/cohabiting | 2178 (3.5) | 143 (61, 302) | 168 (67, 388) | |||
| Smoking prior to pregnancy | ||||||
| Non smoker | 44,005 (71.1) | 142 (66, 277) | 0.026 | 166 (72, 367) | 0.015 | |
| Occasional smoker | 6376 (10.3) | 140 (66, 276) | 165 (72, 368) | |||
| Daily smoker | 11,523 (18.6) | 139 (61, 294) | 164 (66, 377) | |||
| Pre-pregnancy BMI | ||||||
| <18.5 kg/m2 | 1809 (2.9) | 140 (62, 271) | <0.001 | 168 (71, 376) | <0.001 | |
| 18.5–24.9 kg/m2 | 40,457 (65.4) | 142 (67, 278) | 167 (74, 368) | |||
| 25–29.9 kg/m2 | 13,604 (22.0) | 140 (62, 285) | 163 (67, 372) | |||
| ≥30 kg/m2 | 6034 (9.7) | 137 (58, 288) | 160 (63, 372) | |||
| Income | ||||||
| Both <300,000 NOK | 18,929 (30.6) | 143 (63, 291) | <0.001 | 167 (69, 371) | 0.073 | |
| One ≥300,000 NOK | 26,419 (42.7) | 142 (65, 283) | 166 (71, 371) | |||
| Both ≥300,000 NOK | 16,556 (26.7) | 138 (67, 260) | 164 (74, 363) | |||
| Milk and yogurt intake | ||||||
| <200 mL/day | 17,187 (27,8) | 88 (49, 141) | <0.001 | 102 (53, 262) | <0.001 | |
| 200–399 mL/day | 13,378 (21.6) | 122 (84, 175) | 137 (88, 296) | |||
| ≥400 mL/day | 31,339 (50.6) | 183 (123, 320) | 209 (129, 410) | |||
| Fish and seafood intake | ||||||
| <20 g/day | 14,195 (22.9) | 117 (49, 252) | <0.001 | 141 (54, 346) | <0.001 | |
| ≥20 g/day | 47,709 (77.1) | 148 (74, 286) | 172 (79, 376) | |||
| Egg intake | ||||||
| <8 g/day | 19,921 (32.2) | 129 (56, 269) | <0.001 | 153 (61, 357) | <0.001 | |
| ≥8 g/day | 41,983 (67.8) | 146 (71, 283) | 171 (77, 375 ) | |||
| Iodine from supplements | ||||||
| No | 42,329 (68.4) | 141 (65, 279) | <0.001 | 141 (65, 279) | <0.001 | |
| Yes | 19,575 (31.6) | 141 (65, 282) | 252 (122, 466) | |||
* p-Values; unadjusted differences between groups. P5: 5th percentile, P95: 95th percentile.