RESUMEN
Background: This study aimed to investigate the iodine status and its potential effects on thyroid function and autoimmunity in Colombia. Methods: This was a cross-sectional study, in population of urban and rural areas, from four geographic regions in the Department of Cauca, Colombia; the participants were 412 healthy adults, a third from rural areas. The following variables were evaluated: median urinary iodine concentration (mUIC), serum thyrotropin (TSH), clinical and ultrasonographic (US) goiter assessment, and anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-Tg) and anti-TSH receptor (TRAb) concentrations. Results: The mUIC levels were 153.9 µg/L (interquartile range (IQR): 220.06); 30% had "excessive" mUIC and a quarter had "low" mUIC. The positivity of anti-Tg and anti-TPO was higher in subjects > 60 years (P = 0.017 and P ≤ 0.001, respectively). A high prevalence of "low" mUIC was found in the "low" socioeconomic status (SES) and of "more than adequate or excessive" in the "high" SES when compared with the "medium" SES (P ≤ 0.001). The prevalence of goiter by physical examination was 41.7% and 34% by US. The highest mUIC levels were significantly more prevalent in women, in subjects with elevated TSH and in those from rural areas. Conclusions: The population status of iodine in Colombia is U-shaped; the high prevalence of goiter, hypothyroidism, and thyroid autoimmunity can be explained by excess or deficit of iodine and by probable environmental goitrogens.
RESUMEN
Iodine deficiency and iodine excess have severe consequences on human health and have been associated with the presence of goiter, hypothyroidism, hyperthyroidism, thyroid cancer, thyroid nodules and thyroid autoimmunity, poor mental health, and impaired intellectual development. Universal salt iodization programs have been considered one of the most cost-effective interventions for the prevention of iodine deficiency-associated disorders, as evidenced over time since the implementation of such programs. However, these efforts have also led to an excessive consumption of iodine in certain geographical regions, due to salt overuse. Consequently, the amount of iodine derived from salt intake exceeds the established limits required for achieving the right balance between salt consumption and health benefits and leads to undesirable health effects. In Colombia, the recommendations and standards for the production and commercialization of iodized salt are fully complied with. Nevertheless, there is a remarkable rate of iodine excess among the country's population, which, at least hypothetically, represents a higher risk for developing functional and structural disorders of the thyroid gland. This review analyzes universal salt iodization programs worldwide, particularly their impact on the thyroid gland and the results of the studies conducted in Colombia following the implementation of such strategy.