The Pathogenetic Significance of Low Iodine Intake in Non-Endemic Goiter — Absolute Iodine Uptake

Summary

The blood inorganic iodine concentration (BII), the radioiodide clearance and the absolute iodine uptake (AIU) were determined in 27 patients with simple goiter and in 21 controls. The purpose was to evaluate the pathogenetic significance of low iodine intake for the formation of sporadic goiter. An early thyroid radioiodide clearance was measured by ¹³² I (5–30 min post injection), and the BII values were bases on the specific activity of I in saliva.

The median BII levels of patients and controls were 1.1 and 1.5 μg/l respectively, and the urinary iodine excretion 67 and 79 M-g/day respectively, the difference was not significant. The radioiodide clearance was above the normal range in 13 out of 27 patients, and 16 of 27 patients had elevated or high normal AIU values. These patients included 7 out of 9 patients with diffuse, shortlasting goiter; the AIU of those with nodular goiter ranged from slightly subnormal to elevated. Only one exhibited a typical iodine deficiency pattern of very low BII, high radioiodide clearance and normal AIU.

It is concluded that a simple causal relationship between low iodine intake and goiter formation could not be demonstrated.

Bei 27 euthyreoten Patienten mit blander Struma und bei 21 Normalpersonen wurden die Konzentration des anorganischen Jods im Blut (BII), die Radiojodclearance und die absolute Jodaufnahme (AIU) bestimmt, um die Bedeutung niedriger Jodzufuhr für das Auftreten sporadischer Strumen zu beurteilen. Die Schilddrüsenclearance wurde zwischen 5 und 30 Minuten nach der Injektion von ¹³²J gemessen, und die Bestimmung von BII basierte auf der spezifischen Aktivität des Jods im Speichel.

Der mittlere der BII Werte war 1.1 μg/1 Blut bei den Patienten und 1.5μg/l bei den Normalpersonen, der mittlere Wert des Gesamtjods im Harn 67 und 79μg pro Tag, p > 0.05. Die Radiojodclearance war bei 13 der 27 Patienten erhöht, und 16 Patienten hatten AIU Werte, die hoch im oder über dem BH-abhängigen Normalbereich waren. Die Speicherung von ¹²⁷J war bei den meisten Patienten (7/9) mit kurzdauernder diffuser Struma erhöht. Bei den Patienten mit knotigen Strumen wurden subnormale bis erhöhte AJU-Werte gefunden. Nur bei einem Patienten stellte das Bild einen typischen Jodmangel dar, sehr niedriges BII, hohe Radiojodidclearance und normaler AIU.

Ein einfacher ursächlicher Zusammenhang zwischen der Strumaentwicklung und dem Jodmangel war daher nicht nachweisbar.

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