[Assessment of dietary habits related to iodine intake and iodine concentration and thyroid dysfunction in a non-preselected population in Spain (the Thyrobus Project)].

Introduction: Most of the studies on urinary iodine levels in Spain in the last decade have reported a significant improvement. A survey was undertaken together with an information campaign on the thyroid gland, the importance of iodine intake and hypothyroidism in four Spanish cities. The goals of the survey were to obtain information on consumption of iodine-containing foods, to measure urinary iodine levels and to evaluate the prevalence of thyroid dysfunction.

Materials And Methods: A non-preselected population attending the information campaign centers located in Barcelona, La Coruña, Malaga and Madrid was studied. A questionnaire on fish, milk and iodized salt consumption was administered. Urinary iodine levels (Pino's method) and thyrotropin (TSH) concentrations (Whatman 903® dry paper method) were measured.

Results: A total of 872 questionnaires were completed (Madrid 40%; La Coruña 27%; Malaga 19%; and Barcelona 14%). The mean age was 51 years (SD 16); 81% were women. A total of 60.6% of interviewees reported they consumed iodized salt, 90.8% reported daily milk intake and 29.3% reported fish consumption ≥3 times per week. The mean urinary iodine concentration was 143.2 μg/L. The prevalence of high TSH levels (>4 mUI/L) was 1.3% and that of low TSH levels (<0.4 mUI/mL) was 1.2%.

Conclusions: According to the World Health Organization criteria, the median urinary iodine concentration, both overall or by city, is indicative of optimal iodine intake. In addition to iodized salt intake, consumption of products such as milk and fish has probably contributed to these positive results. The prevalences of undiagnosed hyperthyroidism and hypothyroidism detected in this study were similar to those found in other studies.