July - September 2007, Volume 3, Issue 3

Sz?nt? Z, Kun I, Kun IZ, Coros L, Cucerea M

The influence of universal salt iodization on the iodine status reflected by THS serum levels of newborns in Mures County between years 2001-2006

Acta Endo (Buc) 2007, 3 (3): 291-301
doi: 10.4183/aeb.2007.291

Iodine deficiency in a geographical area can be quantified, not only by urinary iodine\r\nexcretion, but also through the incidence of elevated TSH levels measured in newborns. We\r\nmeasured the TSH level in 3015 newborns, in a partial screening realized in Mures County\r\nduring the years 2001–2006. The law for the universal salt iodization with increased KIO3\r\nlevel (34 ? 8.5 mg/kg) was adopted in Romania in 2002, and implemented in practice\r\nstarting with December 2003. We compared TSH levels of 2,454 children born in the years\r\n2001-2003, before the universal salt iodization, with those of 561 children born in 2004-\r\n2006 after the implementation of the law of universal salt iodization. An elevated TSH\r\nlevels (over 10 mUI/L, according to the WHO criteria) was revealed in 8.23 %( 199/2,454)\r\nnewborns during 2001-2003, as compared to 9.62% (54/561) subjects born during 2004-\r\n2006 (p=NS). Based on both criteria and results, Mures County is a region with a\r\nmoderately mild iodine deficiency. However, the mean value of TSH levels (over 12\r\nmUI/L) obtained during 2001-2003, (19.81 ? 2.63 mUI/L, X ? SD, n= 145) significantly\r\ndecreased in the second period (15.63 ?7.35 mUI/L, n=34) (p= 0.02), i.e. a medium decrease\r\nwith 4.18 mUI/L. While the moderate increase of TSH levels (10-12 mUI/L) is an indicator\r\nof iodine deficiency, higher concentrations (>20 mUI/L) usually indicate the coexistence of\r\na hypothyroidism due to the low iodine supply. We observed an important decrease of the\r\nhypothyroidism induced by iodine deficiency: when during the first period its incidence was\r\n2.49%, in the second one it decreased to 1.46% (p=ns). In conclusion, after increasing the\r\niodine-content by universal salt iodization, the incidence of elevated TSH level (and the\r\ncorresponding hypothyroidism) did not decrease in newborns, but the mean value of higher\r\nthan normal TSH presented a statistically significant decrease, reflecting the improvement\r\nin iodine supplementation.

Keywords: iodine deficiency, neonatal TSH levels, universal salt iodization

Correspondence: I.Z. Kun, Endocrinology Department, University of Medicine and Pharmacy, T?rgu-Mures, Romania, Gh. Marinescu Street 38, e-mail: kunimre@rdslink.ro