Table 3.
Urinary iodine, estimated iodine intake and sodium excretion values by salt intake equivalent categories
| 24-hour urinary sodium excretion | |||||||||
| All n=874* | Salt <5 g/day n=307 | Salt 5–9 g/day n=322 | Salt >9 g/day n=245 | P value | |||||
| Median | IQR | Median | IQR | Median | IQR | Median | IQR | ||
| Sodium (mg/day) | 2471 | 1434, 3506 | 1393 | 1068, 1719 | 2638 | 2219, 3057 | 4799 | 3607, 5993 | <0.001 |
| Salt (g/day) | 6.3 | 3.7, 9.0 | 3.6 | 2.8, 4.5 | 6.8 | 5.7, 7.9 | 12.3 | 9.3, 15.4 | <0.001 |
| UIC (µg/L) | 130 | 58, 202 | 102 | 32, 172 | 131 | 56, 206 | 149 | 78, 220 | <0.001 |
| 24-hour UIE (µg/day) | 117 | 48, 186 | 74 | 37, 111 | 119 | 57, 181 | 195 | 117, 273 | <0.001 |
| Estimated iodine intake (µg/day)† | 127 | 52, 202 | 80 | 40, 120 | 130 | 63, 197 | 212 | 127, 297 | <0.001 |
| % with daily iodine intake below EAR for iodine (95 µg/day) | 37.1 | 58.4 | 34.7 | 13.5 | |||||
*One individual in subsample with missing 24-hour sodium analysis. Data shown as median and IQR (25th, 75th percentiles). Continuous variables compared using independent samples Kruskal-Wallis test.
†Daily iodine intake assumed as 24-hour UIE (µg/day)/0.92 to account for bioavailability.
EAR, Estimated Average Requirement; UIC, spot urinary iodine concentration; UIE, 24-hour urinary iodine excretion.