Iodine nutritional status in the adult population of Shandong Province (China) prior to salt reduction program.

Purpose: Tremendous differences in iodine status and daily iodine intake persist across provinces of China. The objective of the present study was to evaluate the iodine status and dietary iodine intake of Shandong adults before the implementation of the salt reduction program and a new salt iodization standard.

Methods: Data from a baseline survey of the Shandong and Ministry of Health Action on Salt Reduction and Hypertension project (2011) were analyzed. The iodine contents of 1949 24-h urine samples and 136 drinking water samples were assayed. Daily urinary iodine excretion and daily iodine intake were calculated, analyzed, stratified by different analytical variables and compared with Chinese Dietary Reference Values.

Results: The median urinary iodine concentration and median daily iodine intake of Shandong adults were 248.5 μg/L and 368.2 μg/day, respectively. The median iodine intake of different groups was between the estimated average requirements and the upper limit, except group in water iodine >300 μg/L with median iodine intake of 1200.7 μg/L. Salt intake and iodine levels in drinking water related to iodine intake significantly.

Conclusions: Shandong adults had more than adequate iodine nutrition, and the dietary iodine intake of the population was generally appropriate and safe except residents in high water iodine areas. In the context of the implementation of a salt reduction program and a new salt iodization standard, the iodine status of high water iodine areas may remain in the recommended level, but in low water iodine areas, the risk of inadequate iodine intake may increase, needing monitoring of urine iodine excretion, dietary iodine intake and iodized salt consumption regularly.