Adequate iodine nutrition and higher salt intake in Chinese adults compared with WHO recommendations

Objective: Iodine deficiency and excessive salt intake have adverse health effects. This study evaluated the iodine level and salt intake in Chinese adults after implementing the salt reduction program and compared both with the World Health Organization (WHO) recommendations. Methods: ： Adults aged 18–59 years were randomly selected using multi-stage stratified random sampling in Fujian Province, China. Iodine, sodium, and creatinine concentrations in spot urine samples were measured. Knudsen equation was used to determine 24-h urinary iodine and sodium excretion. Results: : The median urinary iodine concentration (mUIC) among adults ( n = 3513) was 132.0 μg/L. No significant differences were observed in mUIC between sexes and age groups ( P > 0.05). The median daily salt intake (DSI) among Chinese adults was 10.2 g/d, and only <13.6% of the population met the recommended WHO upper DSI level of 5 g/d. The DSI of residents was higher in the noncoastal rural areas than in the other three areas ( P < 0.05). The adults aged 45–59 years consumed more salt compared with those aged 18–49 years ( P < 0.05). The logistic regression demonstrated that the people living in coastal and noncoastal urban areas consumed less salt compared with those in noncoastal rural areas. Except for noncoastal urban areas, the daily iodine intake was lower (<150 μg/d) among women of childbearing age in the low–salt intake group (<5 g/d) ( P < 0.05) compared with the high–salt intake group (≥5 g/d). Conclusions: ： Iodine nutrition in Chinese adults was sufficient, but the salt intake was substantially higher than the WHO recommendations. Further policy implementation is needed to reduce salt intake and improve the monitoring of iodine levels in Chinese adults, especially in women of childbearing age.