[Marked reduction in goiter prevalence and eventual normalization of urinary iodine concentrations in Iranian schoolchildren, 10 years after universal salt iodination [third national survey of iodine deficiency disorders 2000]]

Two years after legislation of salt iodization of 40 parts per million [ppm] in 1994, goiter was still endemic and urinary iodine concentration [UIC] remained elevated in many provinces of Iran. Goiter prevalence and UIC were compared two and seven years after sustained consumption of uniformly iodized salt by Iranian households. From December 2000 to June 2001, schoolchildren [7-10 yr] of all provinces were randomly selected by cluster sampling; their goiter rate, UIC, and household salt iodine levels were compared to similar data collected in 1996. Factory salt iodine produced in 2001 was also compared to that of 1996. Ultrasonographically determined thyroid volumes of 7-10 yr old children were compared in 2001 to those of 1999. Total, grade 1, and grade 2 goiters were 13.9 vs. 53.8%, 11.0% vs. 44.8%, and 2.9% vs. 9.0%, in 2001 [n=33600] vs. 1996 [n=36178], respectively [p<0.0001]. Median [range] UIC in 2001 [n=3329] was 165 [18-410] micro g/L and in 1996 [n=2917] was 205 [10-2300] micro g/L [P<0.0001]. Means for iodine salt content were 32.7 +/- 10.1 and 33.0 +/- 10.2 [P=0.79] in households and 33.2 +/- 13.4 and 33.8 +/- 13.2 [P=0.67] in factories, in 2001 and 1996, respectively. Only 7-yr-old children in 2001 [the only group with probably no history of iodine deficiency] showed significantly smaller thyroid volumes compared to those in 1999. After seven years of optimized iodized-salt supplementation in Iran, adequate UIC values and marked reduction in goiter rate have been achieved

Acid digestion and microplate reading method for milk iodine determination

Main shortcomings in existing methods for iodine determination in milk samples are non safe alkaline solution, harsh thermal conditions, and their being time consuming. In this study, for determination of total iodine content in milk, a simple and rapid kinetic catalytic colorimetric, acid digestion and rapid microplate reading format method, was investigated. Sample digestion was done on 50 micro L milk in metavanadate/perchloric acid, at 230°C for 10 min. After digestion, iodine determination was based on famous Sandell - Kolthoff reaction. The reaction results were read in 96 wells microplate by ELISA reader. Work range of the assay was between 2-40 micro g/dl. The within-run coefficient of variation percent ranged from 6. 7 to 9. 3 and between-run coefficients of variation ranged from 8.6 to 12.3%. The results obtained [n = 70] by the optimized method had good correlation with the results of alkaline incineration as the reference method [p < 0.000, n = 70 r2 = 0.907 y = 0. 952x-0.084]. Recovery tests for accuracy assessment were between 91.3 to 113%. This method enabled us to achieve 0.1 micro g/dl sensitivity. This study showed that, fast acid digestion, mild thermal, fast results reading and low sample volume, were the main advantages of the acid digestion and microplate reading format investigated

[Positive interference in Radioimmunoassay determination of serum total T3]

Determination of thyrotropin, total and free thyroxine and triiodothyronine are widely used as diagnostic methods for thyroid function evaluation. There have been numerous reports of interferences in thyroid hormone immunoassays. Herein, a prominent positive interference is reported for a radioimmunoassay kit of total triiodothyronine. In this study, a total of 3471 patients, referred by endocrinologists, were examined by serum level measurement of thyroid stimulating hormone [TSH], total thyroxine [T4] and triiodothyronine [T[3]]. T[3] analysis was made through a competitive solid-phase radio labeled [I[125]] immunoassay by T[3] Izotop kit [Izotop Co. Budapest, Hungary]. The presence of T[3] assay interference was considered probable if the hormone profile was inconsistent with the clinical picture and/or the obtained value for T[3] was extremely deviated from normal levels, i.e. it was above 780 ng/dL. For such patients, the possibility of T[3] assay interference was investigated through re-measuring T[3] level by another RIA kit [Immunotech kit, Marseille, France]. Among 3471 patients studied, 40 cases [36 women, 4 men], with a mean +/- D age of 38.8 +/- 15.0 years, had T3 serum levels inconsistent with their clinical pictures and/or above 780 ng/dL. The mean serum levels of T4 and TSH in this group were 9.0 +/- 2.0 micro g/dL and 1.79 +/- 1.47 micro U/mL, respectively. In all these 40 cases, T[3] level was in the normal range according to T[3]-Immunotech kit [with a mean +/- SD of 132.k1 +/- 31.0 ng/dL], in accordance with their clinical pictures. Results clearly indicate the presence of positive interference[s] in some of T[3] assays made with Izotop T[3]-RIA kits. The probable explanations for the observed positive interference are discussed

high prevalence of severe congenital hypothyroidism: a necessity for an effective strategy of detection and treatment in the national screening program for neonatal hypothyroidism

The high prevalence of congenital hypothyroidism [CH] has been reported previously, however the severity of CH has not been evaluated yet. This report illustrates the severity of CH in Tehran and Damavand.From February 1998 to May 2003, 31 hypothyroid neonates [>37 weeks gestation] were detected during the CH screening program in Tehran and Damavand. Neonates were grouped in permanent [n=25] and transient CH [n=6]. Those in the permanent CH were assigned in Dysgenetic [n=18] and dyshormonogenetic [n=5] groups. Dysgenetic cases were further classified in ectopic-hypoplastic [n=13] and athyroitic [n=5] cases. Serum thyroxine values and frequency distribution of sever hypothyroidism [T4<42.8nmol/L] were compared among the groups.Mean [ +/- SD] of T4 of permanent CH [38.0 +/- 42.2 nmol/l] was significantly lower than transient CH [101.9 +/- 46.5 nmol/l] [p < 0.01]. It was similar in dysgenetic [41.9 +/- 47.5 nmol/l] and dyshormonogenetic [27.8 +/- 23.7 nmol/l]. Both latter groups shoed significantly lower T4 values than transient CH [p < 0.05]. Athyreotic cases [11.1 +/- 5.9 nmol/l] had lower T4 levels than transient CH [p < 0.05]. Severe CH was present in 18[72%] permanent, 1[16.7%] transient, 8[61.5%] ectopic-hypoplastic, 5[100%] athyroitic, and 5[71.4%] dyshormonogenetic CH cases. Odds ratio of severe CH occurrence in permanent CH as compared to transient CH was 12.9[95% CI: 1.27-130.54].The high prevalence of severe CH warrants an effective national CH screening program for early detection of CH cases and sufficient replacement therapy

Screening for congenital hypothyroidism in the Islamic Republic of Iran: strategies, obstacles and future perspectives

The operational feasibility of a congenital hypothyroidism [CH] screening programme was assessed. Cord blood spot specimens were collected at seven Teheran hospitals and within the Damavand District health network. Cord thyroid-stimulating hormone [TSH] levels > or = 20 mU/L were recalled and levothyroxine [L-T4] therapy was started immediately after diagnosis of CH. Of 20,107 acceptable specimens, 22 neonates had CH [1:914 births]. The recall rate was 1.3%. Screening coverage was 90% of live births. Of all cord samples, only 0.2% were unacceptable either because of delay in transportation or improper specimen collection. Median ages at the time of diagnosis and starting treatment were 12 and 8 days respectively. Screening for CH is feasible and a national screening programme is a necessity