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Endemic goiter and iodine deficiency status among Guinea-Bissau school-age children



Iodine deficiency disorders are estimated to affect 25% of all school-age children around the world. Current policies concerning iodine deficiency disorders in many countries are not based on robust or recent national data. Our objective was to evaluate the current status of iodine nutrition in Guinea-Bissau (West Africa).


A cross-sectional survey including 299 school-age children, aged 6–14 years old, from four distinct regions of Guinea-Bissau across a coast-hinterland gradient (Bolama, Bissau, Cambaju-Bafatá, and Gabú) was performed. Several iodine deficiency disorders indicators were used: total goiter rate, median urinary iodine concentration (UIC) and regional iodine content in household salt and drinking water samples. Data on the total goiter rate were obtained by thyroid ultrasound.


Goiter was found in 73.5% (CI 95%, 68.5–78.2%) of the school-age children. We observed a median urinary iodine concentration of 110  mcg/l, with 7.3% of the studied population presenting urinary iodine concentration  < 50  mcg/l. Only 12.5% of the household salt samples revealed iodine content ≥  15  mg/kg. Median well water iodine concentration was 11.7  mcg/l.


Guinea-Bissau presents high rates of goiter in school-age children despite satisfactory median urinary iodine concentration population levels. Salt and drinking water iodine median content cannot explain these findings. Further studies following the progress in iodine deficiency status and the presence of potential goitrogens in diet of this vulnerable population are in needed.

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Fig. 1
Fig. 2: Frequency histogram of urinary iodine concentration (UIC) in Guinea-Bissau school children (n = 299).


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We wish to thank all children and families who agreed to participate in this study; Alfucene Dabo and Víctor Madrigal from Ayuda, Intercambio y Desarollo (AIDA), Bissau—Guinea-Bissau, for the logistic support; Professor Joana Palha from the Life and Health Sciences Research Institute (ICVS), University of Minho, Braga—Portugal, for the portable US; and to Hugo Ribeiro for his technical support with the screening of urine samples.

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Corresponding author

Correspondence to Andre Couto Carvalho.

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Compliance with ethical standards

This study was conducted according to the guidelines laid down in the Declaration of Helsinki and all procedures involving human subjects were approved by the ICBAS-University of Porto. Verbal informed consent was obtained from all subjects or guardians. Verbal consent was witnessed and formally recorded.

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

A poster with part of this work was presented at the 36th Annual Meeting of the European Thyroid Association, Pisa, Italy in September 2012 and published as an abstract in the Eur Thyroid J 2012;1(suppl 1):75–208.

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Carvalho, A.C., Machado, A., Embalo, A.R. et al. Endemic goiter and iodine deficiency status among Guinea-Bissau school-age children. Eur J Clin Nutr 72, 1576–1582 (2018).

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