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Table 4 Concentration of thyroid indices if urinary iodine concentration (UIC) <50 μg/L or ≥50 μg/L and <100 μg/L or ≥100 μg/L

From: A comprehensive assessment of urinary iodine concentration and thyroid hormones in New Zealand schoolchildren: a cross-sectional study

 

Tg (μg/L)

P

TSH (mU/L)

P

Free T4 (pmol/L)

P

Free T3 (pmol/L)

P

Mean (95% Cl)

 

Mean (95% Cl)

 

Mean (95% Cl)

 

Mean (95% Cl)

 

UIC < 50 (μg/L)

15.6 (14.0,17.3)

0.001

1.7 (1.6, 1.9)

0.669

14.7 (14.3,15.2)

0.271

6.1 (6.0,6.2)

0.002

UIC ≥ 50 (μg/L)

12.3 (11.1, 13.5)

 

1.7 (1.6, 1.8)

 

15.0 (14.6, 15.3)

 

5.9 (5.8, 6.0)

 

UIC < 100 (μg/L)

13.9 (12.8, 14.9)

0.000

1.7 (1.6, 1.8)

0.236

14.9 (14.5, 15.2)

0.630

6.0 (6.0, 6.1)

0.001

UIC ≥ 100 (μg/L)

10.3 (8.8, 12.1)

 

1.8 (1.6,1.9)

 

15.0 (14.5, 15.5)

 

5.9 (5.8, 6.0)

 
  1. Tg and TSH values presented as geometric mean (95% Confidence Interval) and free T4 and T3 values presented as mean (95% Confidence Interval) as determined by regression analysis. Values of 50 μg/L and 100 μg/L based on ICCIDD/UNICEF/WHO [7] recommended cut-offs for UIC. Thyroglobulin = Tg.