[SERUM THYROGLOBULIN LEVELS AND ESTIMATED IODINE INTAKE IN ADULTS EXPOSED TO IODINE‑DILUTED DESALINATED DRINKING WATER].

AIMS: The aim of this study was to describe thyroglobulin levels and iodine intake estimations in a convenience sample of Israeli adults without TD in the Ashkelon District, where SWRO desalination has become the major source of drinking water.

BACKGROUND: Iodine deficiency (ID) is a significant risk factor for thyroid disease (TD). Recently, there were increases in both selfreported use of TD medication among Israeli adults and the national use of sea water reverse osmosis (SWRO) desalinated water.

METHODS: Iodine concentrations in tap water (supplied by Mekorot Israel National Water Co.) were estimated before and after SWRO desalination was implemented in the Ashkelon District. Volunteers were recruited at the Barzilai Medical Center Ashkelon between January 2012 and October 2013. Data regarding residency, BMI and use of iodine-containing or steroidal drugs were obtained for all volunteers. Blood was drawn from matching participants for determination of serum thyrotropin, thyroid peroxidase antibodies, thyroglobulin (Tg) antibodies and Tg. A semi-quantitative iodine food frequency questionnaire (sIFFQ) was administered.

RESULTS: Iodine concentration estimation in tap water declined from 52 μg/L to 27 μg/L after SWRO desalination was implemented in the Ashkelon District. A total of 50 participants without reported or known TD were included in the study after screening 92 volunteers. The median serum Tg was 21 ng/mL, and 76% (35 participants) had elevated values (Tg ≥ 10 ng/mL), indicating a high prevalence of apparent ID. Iodine intake estimation (median 99 μg/d by sIFFQ) was lower than the Recommended Dietary Allowance (150 μg/d). Unfiltered tap water was estimated to provide 16% of the mean daily iodine intake.

CONCLUSIONS: The finding of apparent ID in this sample, underscores the need to obtain further data regarding many other regions across Israel. This is particularly urgent in the context of Israel's increased dependence on SWRO desalination.