Intakes of dairy products and dietary supplements are positively associated with iodine status among U.S. children

Although pregnant womenand some groups of reproductive-age women in the US may be at risk of iodine deficiency, data also suggest that iodine intake among many U.S. children may be above requirements. Our objective was to describe the association of iodine sources with iodine status among children. We analyzed 2007‐2010 NHANES data of urine iodine concentration (UIC) spot tests for children aged 6‐12 y (n = 1553) and used WHO criteria for iodine status (median UIC: 100‐199 mg/L = adequate; 200‐299 mg/L = above requirements; $300 mg/L = excess). The overall median UIC was above requirements for children aged 6‐12 y [211 mg/L (95% CI: 194, 228 mg/L)]. Median UIC increased by quartile of previous day dairy intake, ranging from adequate in the lowest quartile [157 mg/L (95% CI: 141, 170 mg/L)] to above requirements in the highest quartile [278 mg/L (95% CI: 252, 336 mg/L)]. Median UIC was 303 mg/L (95% CI: 238, 345 mg/L) among the 17% of children who had taken a dietary supplement containing iodine the previous day, compared with 198 mg/L (95% CI: 182, 214 mg/L) among those who had not. In adjusted regression analyses, recent dairy intake and recent supplement use were significantly positively associated with UIC levels, whereas recent grain intake was negatively associated. Adding salt to food at the table was not associated with UIC. Iodine-containing supplements are likely not needed by most schoolchildren in the US because dietary iodine intake is adequate in this age group. J. Nutr. 143: 1155‐1160, 2013.