Spot urinary iodine concentration as a measure of dietary iodine, evaluated in over 3800 young male subjects undergoing medical check-up preliminary to military enrolment in Piemonte and Aosta Valley (Italy)

Abstract

The aim of the study was to assess iodine status in over 3800 young male subjects aged 18, living in 6 different provinces of Piemonte and in Aosta Valley, Italy. A cross-sectional study on 3837 young male subjects undergoing medical evaluation preliminary to military enrolment was performed. Spot urine samples were obtained in the morning hours and urinary iodine was measured by a colorimetric method. As outcome measure iodine status, based on spot urinary iodine median concentration, categorised as sufficient (>99 microg/l), mild deficiency (50-99 microg/l), moderate deficiency (20-49 microg/l) and severe deficiency (<20 microg/l), was obtained. Median urinary iodine concentration was 101.8 microg/l in our sample. Moderate-to-severe iodine deficiency was found in <10% of all subjects. Mild iodine deficiency was found in <40% of the subjects, with greater variability within the provinces considered. For each geographical area significant differences can be observed in more than 50% of the comparisons of the confidence intervals related to the frequencies of samples with spot urinary iodine concentration below 100 microg/l. The high frequency of mild iodine deficiency found in our sample suggests that dietary sources of iodine in Piemonte, Italy, have improved since the last evaluation 25 yr ago (2) but may still be insufficient. Further population studies are required.

Thyroid cancer incidence and survival among European children and adolescents (1978–1997): Report from the Automated Childhood Cancer Information System project

“…Our observation cannot be considered conclusive though, because of the heterogeneity of io- dine status within countries and on an individual level. 42 Furthermore, the geographical areas defined for this study may not correspond with the areas of predilection of factors modulating incidence levels. In Belarus, the spectacular increase in thyroid carcinomas might have been reinforced by the moderate iodine deficiency around Chernobyl, shown to increase the odds of developing thyroid cancer after a 1-Gy exposure in the most deficient areas to 3.2 (95% CI 1.9-5.5).…”

Evaluating iodine deficiency in pregnant women and young infants—complex physiology with a risk of misinterpretation

“…The impact of this was considerable. For example, Fonzo et al 21 studied UI excretion in over 3800 young men in Piedmonte and the Aosta Valley, a formerly severely iodine-deficient area in Italy. The median UI concentration was 101.8 μg l − 1 and the conclusion was that iodine intake may still be of borderline sufficiency.…”

“…For these reasons, the iodine/creatinine ratio came into discredit and was replaced by the simple concentration of iodine in urine 18 . This corresponds to 24 h UI excretion if the volume of urine produced by the group under study is 1 l day 21 , as it may be in schoolchildren. However, in adolescents and adults, the average urine volume is more likely 1.5 l per 24 h, and therefore, an iodine concentration of 100 mg l 21 corresponds to an iodine excretion of approximately 150 mg per 24 h.…”

“…2, reliable estimates of the 24 h Fig. 1 The average urinary iodine (UI) excretion (mg day 21 ) and the prevalence of goitre by clinical examination in people in 186 localities in Central America between 1965 and 1967 14 . In each locality, members of approximately 20 randomly selected families were investigated.…”

“…In a study performed in Sydney, Australia, McElduff et al found a positive correlation between the maternal UI concentration during pregnancy and the neonatal serum TSH concentration 35 . The median concentration of iodine in the urine of mothers (n ¼ 84) was 109 mg l 21 . Similarly, the same researchers found a positive correlation between the concentrations of TSH in neonates and the concentration of iodine in breast-milk 36 .…”