Endocrine Abstracts

Goiter prevalence (GP) and median UIC in population studies are both considered markers of iodine nutrition. Controversy exists which of them is more reliable.

Aim: To assess correlation between UIC and thyroid volume in Polish schoolchildren.

Material and methods: 9402 Polish schoolchildren (51.3% girls, 48.7% boys) aged 6–12 years were examined in 1999–2011 (‘Thyromobil’ action). 40.9% of children were born at least one year after implementation of obligatory iodine prophylaxis (IOIP). TV was assessed ultrasonographically, GP was evaluated according to both 1997 and 2004 WHO reference values. To avoid age influence TV(ml)/BSA(m2) ratio (TVBR) was calculated. UIC in urine spot samples was measured by Sandel-Kolthoff’s method.

Results: Median UIC was 96.18 mcg/l. Median TVBR was 3.97 ml/m2. GP for age (GPA) was 5.5% and 55.7%, for BSA 4.9% and 56.5% according to 1997 and 2004 reference, respectively. GPA was 5.7% and 5.2% according to 1997 reference, and 56,8% and 54.5% according to 2004 reference, for UIC < and ≥100 mcg/l, respectively. GPA was 6.5% and 4% according to 1997 reference, and 56.6% and 58.7% according to 2004 reference, for children born before and after IOIP, respectively. Median TVBR was 4.1 and 3.8 ml/m2 (P<0.0001) for children born before and after IOIP, respectively. Median UIC was 91 and 104.3 mcg/l (P<0.001), for children born before and after IOIP, respectively. Median UIC was 96.5 and 91.9 mcg/ml (P=0.43), and 97.8 and 95.0 mcg/l (P=0.025) for children without and with goiter according to 1997 and 2004 age reference, respectively. TVBR was 4.05 and 3.97 ml/m2 (P<0.0001) for UIC < and ≥100 mcg/l, respectively. Negative, statistically significant correlation between TVBR and UIC was observed (r=−0.033, P<0.005).

Conclusions: Statistically significant correlation between UIC and TV was confirmed. However, neither 1997 nor 2004 WHO reference values seem to reliably estimate influence of iodine prophylaxis on TV.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.