Table 3.
Association between iodine content in salt and urinary iodine during early and late pregnancy
| Salt Iodine (ppm) | Urinary Iodine | ||
|---|---|---|---|
| Median (IQR) | Unadjusted ratio of geometric mean (95% CI) | Adjusted ratio of geometric mean (95% CI)* | |
| Early pregnancy | |||
| <5.0 | 47.6 (26.3, 84.3) | 0.4 (0.4, 0.6) | 0.4 (0.4, 0.6) |
| 5–9.9 | 60.9 (31.8, 100.0) | 0.5 (0.4, 0.7) | 0.5 (0.4, 0.7) |
| 10–14.9 | 91.0 (45.9, 151.6) | 0.8 (0.6, 1.0) | 0.7 (0.5, 0.9) |
| 15–19.9 | 116.6 (55.0, 238.1) | 1.0 | 1.0 |
| 20–29.9 | 161.4 (71.8, 286.4) | 1.3 (1.0, 1.7) | 1.3 (1.0, 1.8) |
| 30–39.9 | 157.4 (104.8, 335.8) | 1.6 (1.1, 2.1) | 1.5 (1.1, 2.1) |
| ≥40.0 | 278.0 (132.1, 519.9) | 2.0 (1.5, 2.8) | 2.0 (1.4, 2.8) |
| P for trend | <0.001 | <0.001 | <0.001 |
| Late pregnancy | |||
| <5.0 | 41.1 (21.3, 66.7) | 0.5 (0.4, 0.6) | 0.4 (0.3, 0.6) |
| 5–9.9 | 49.4 (27.4, 92.8) | 0.6 (0.4, 0.7) | 0.5 (0.4, 0.7) |
| 10–14.9 | 61.0 (27.6, 106.9) | 0.6 (0.5, 0.9) | 0.6 (0.5, 0.9) |
| 15–19.9 | 88.2 (59.8, 141.0) | 1.0 | 1.0 |
| 20–29.9 | 109.3 (54.0, 194.0) | 1.0 (0.8, 1.4) | 1.0 (0.7, 1.4) |
| 30–39.9 | 126.8 (55.6, 232.6) | 1.3 (0.9, 1.8) | 1.3 (0.9, 1.8) |
| ≥40.0 | 203.4 (97.7, 346.3) | 2.1 (1.5, 3.0) | 2.0 (1.3, 3.0) |
| P for trend | <0.001 | <0.001 | <0.001 |
*
Adjusted in early pregnancy for subscapular skinfold thickness, ownership of cropland, fish and leafy vegetables intake, and in late pregnancy for subscapular skinfold thickness, education and, fish, egg, leafy vegetables, other vegetables and fruits intake. CI, confidence interval; IQR, interquartile range.