Discussion
UIE, goiter, iodine deficiency
GOITER, IODINE DEFICIENCY
To the best of our knowledge, this is the first study on the iodine status of Portuguese working adults, using gold standard methodology.Based on previous epidemiological studies performed in school-aged children [With a median 24-h UIC of 66 μg/L, 30% of the population showing 24-h UIC below 50 μg/L, and a daily iodine intake of 112 μg/day, this study revealed that the adult working population had a mild iodine deficiency according to the WHO guidelines for iodine status (median UIC < 100 μg/L plus > 20% of the population with a UIC ≤ 50 μg/L), and the EFSA iodine intake threshold of 150 μg/L. In the literature is argued that the extrapolation from the observed correlation between increasing goiter and a UIE < 100 µg/day to a spot sample UIC below 100 µg/L, as indicative of ID, may have been applicable in children but was not correct for adults [From a public health perspective, the mild iodine deficiency found in this study reinforces the need to implement supplementation strategies for the whole, but especially for women of childbearing age to meet the increased needs in a future pregnancy and secure a normal development of the fetus. Indeed, iodine inadequacy was found in Portuguese pregnant women more than a decade ago [Despite the lower value displayed by the 24-h recall approach, both methodologies applied to estimate the daily iodine intake correlated well. The discrepancy found could be explained by incomplete information on iodine content in foods in the national databases and the self-reported 24-h recall. The 24-h dietary recall indicated that 56.7% of the total iodine intake comes from ingested food. Although the intestinal absorption of ingested iodine is considered to be high (more than 90%), the iodine concentration in water and foods is highly variable [Cereals, fruit, vegetables, and legumes are generally poor iodine sources, and the levels present depend on the amount of iodine in the soil where the plants are grown. Worldwide, 30% of the population lives in areas with iodine-deficient soil [The contribution of the discretionary salt to the daily iodine intake was 43% (52 μg), estimated by the difference between the total daily intake (mean 121 μg/day based on UIE), and the iodine amount provided by food (mean 69 μg/L based on the 24-h dietary recall). In the IMC Salt study, the average salt intake at baseline was 8 g/day [Considering the sodium-healthy diet, as preconized by WHO [The iodization of the salt used in households is the primary strategy to prevent iodine deficiency at a population level [If an iodoprophylaxis was followed, with the fortification of the household and food industry salt, and retaining the average contribution of iodine from food estimated in this study, the daily iodine intake would be 168–199 µg in a sodium-healthy diet, already accounting for the inevitable 20% lost during cooking [