Endocrine Abstracts

Iodine deficiency (ID) and ID disorders (IDD) are a global problem. ID elimination would significantly contribute to achieving at least 6 of the 8 millennium developmental goals.

Aim: To adapt the Neonatal thyroid screening (N?S) based on TSH with a view to its applicability as a permanent indicator in monitoring the effect from the iodine prophylaxis of IDD in Bulgaria.

Tasks: To study: 1) dependence of TSH on age after birth; 2) influence of perinatal application of iodine-containing desinfectants on TSH concentration in newborn children (NB); 3) TSH – distribution prospectively; 4) commercially available iodized salt according to the new state standard (KIO3 28–55 ppm) and its relation to the percentage of TSH >5 mU/l.

Material and methods: TSH analysis (Delfia) from NTS of 619 898 NB from all over Bulgaria (1997–2006) by specially designed software for registering each screened NB. The TSH concentration of 5 mU/l in <3% of NB was used as a sign of iodine repletion (WHO proposal).

Statistics: SPSS 10.

Results: Obvious, significant dependency of TSH on age/inversely proportional/and the application of iodine-containing desinfectants/directly proportional. The percentage of NB in Bulgaria with TSH > the suspicious for congenital hypothyroidism (cutoff 15 mU/l) rapidly decreased (1.8–0.09%; P<0.0001). The relative share of NB on L-thyroxine treatment increased from 25 to 70%. The significant reduction of NB with TSH>5 mU/l and levels <3% (first time in 2006) was accompanied by previous stable, sustainable increase of iodized food grade salt above 90%.

Conclusion: Universal salt iodization is an effective strategy for ID elimination. Bulgaria has reached the first stage of sustainable control over ID. NTS, after thorough ?daptation, might be a useful instrument in monitoring the effect of programmes for securing optimal iodine supplementation at population level among the most sensitive to ID individuals represented by the NB.