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.

Prevalence and correlates of vitamin D deficiency in a tropical setting: results from a nationally representative survey.

BACKGROUND: The prevalence of vitamin D deficiency (VDD) may be high in countries with abundant sun exposure year-round, but nationally representative data are lacking. OBJECTIVE: We examined the prevalence and distribution of VDD by individual and environmental characteristics in a nationally representative sample of Colombian children, pregnant women, and adult nonpregnant women. METHODS: Using the 2015 Colombian National Nutrition Survey, we defined VDD and low vitamin D (LVD) as serum 25-hydroxyvitamin D [25(OH)D] <30 nmol/L and <50 nmol/L, respectively, in 31,841 children aged 1 to <18 y, 1262 pregnant women, and 7170 nonpregnant women aged 18-49 y. Within each group, we compared VDD and LVD prevalence by levels of sociodemographic, anthropometric, and geographic factors using adjusted prevalence ratios with 95% CIs from multivariable Poisson regression. RESULTS: The mean ± SE 25(OH)D was 65.1 ± 0.4 nmol/L. The prevalence ± SE of VDD and LVD was 3.1% ± 0.3% and 23.9% ± 0.8%, respectively. Pregnant women had the highest VDD prevalence at 6.7% ± 1.5%, whereas toddlers had the highest prevalence of LVD at 42.5% ± 1.8%. Altitude was one of the strongest correlates of VDD and LVD, with every 100 m above sea level related to a 4% increase in LVD prevalence (P <0.0001). Among children, VDD was positively associated with BMI-for-age Z >1 and maternal education. Among pregnant women, VDD was positively related to education. Among adult nonpregnant women, VDD was associated with BMI and household wealth. CONCLUSION: The prevalence of VDD and LVD in Colombian women and children is nonnegligible; some age groups are disproportionately affected. Altitude was a strong predictor of vitamin D status in this tropical setting. VDD was positively related to indicators of higher socioeconomic status.