Median Urinary Iodine Concentration in Colombian Children and Women is High and Related to Sociodemographic and Geographic Characteristics: Results from a Nationally Representative Survey.

Background: Salt iodization has been mandatory in Colombia for over half a century. The iodine status of the population has not been recently evaluated using nationally representative data.

Objective: We estimated the median urinary iodine concentration (mUIC) of Colombian women and children overall and by individual and environmental characteristics.

Methods: Using data from spot urine samples collected in the 2015 Colombian National Nutrition Survey, we estimated mUIC in 24,248 boys and girls aged 1 to <13 y and 9122 women of reproductive age (WRA). Within each group, we compared mUIC by levels of sociodemographic, anthropometric, and geographic factors by using adjusted median differences with 95% CIs from quantile regression models.

Results: mUICs were 395 ± 3 μg/L among children and 381 ± 3 μg/L among WRA. Schoolchildren 5 to <13 y old had higher mUIC (407 ± 3 μg/L) than did preschoolers or toddlers. Girls had 21 μg/L (95% CI: -29, -14) lower mUIC than boys after adjustment. In addition, among children, mUIC was positively associated with household wealth and inversely associated with indigenous compared with mestizo ethnicity, living in the southern or Pacific compared with the central regions of Colombia, and altitude. Among WRA, mUIC was positively associated with obesity and inversely with age, indigenous compared with mestizo ethnicity, education, household wealth, living in southern compared with central Colombia, altitude, and alcohol intake frequency.

Conclusion: Colombian children and WRA had mUIC well above conventional cutpoints of iodine excess. Whether excessive iodine affects other subpopulations and its functional consequences warrant urgent investigation.