Hypertension, Dietary Salt Restriction, and Iodine Deficiency Among Adults

BACKGROUND: A common recommendation for the treatment of hypertension is dietary salt intake restriction. However, dietary salt is one of the major sources of iodine. This study evaluated the association between dietary salt restriction and iodine deficiency among adults in the United States. METHODS: Multiple regression models, which controlled for confounders, were used to evaluate the association between hypertension conditions, salt restriction and iodine deficiency among 996 men and 960 women in the blood pressure and iodine subsamples of the 2001-2004 waves of the National Health and Nutrition Examination Surveys (NHANES). RESULTS: High proportions of men (24.96%) and women (40.42%) were iodine deficient. Current hypertension or having a history of hypertension among men and women did not associate significantly with iodine deficiency or high iodine status, compared with those without current or history of hypertension. Compared with men not restricting dietary salt, salt restriction did not associate significantly with iodine deficiency among men. Compared with women not restricting dietary salt, women who were restricting dietary salt associated with significantly lower urinary iodine concentration (UIC), P = 0.01, and were more likely to be iodine deficient, adjusted odds ratios, 1.79, P = 0.03. CONCLUSIONS: Salt restriction associated with iodine deficiency among women but not men. Alternative sources of iodine should be suggested to persons who are consuming low levels of iodine such as women if they need to restrict dietary salt intake. Among those iodine deficient, health professionals should enquire about salt restriction.