Relationship between Dining Place, Iodine Source, and Iodine Nutrition in School-Age Children: A Cross-Sectional Study in China

Abstract

Objective: This study assesses the impact of iodine-rich processed foods and dining places on the iodine nutritional status of children.

Methods: School-aged children (SAC) in seven provinces in China were selected by school-based multi-stage sampling. Urinary iodine, salt iodine, and thyroid volume (TVOL) were determined. Questionnaires were used to investigate dining places and iodine-rich processed foods. The water iodine was from the 2017 national survey. Multi-factor regression analysis was used to find correlations between variables.

Results: Children ate 78.7% of their meals at home, 15.1% at school canteens, and 6.1% at other places. The percentage of daily iodine intake from water, iodized salt, iodine-rich processed foods, and cooked food were 1.0%, 79.2%, 1.5%, and 18.4%, respectively. The salt iodine was correlated with the urinary iodine and TVOL, respectively (r = 0.999 and -0.997, P < 0.05). The iodine intake in processed foods was weakly correlated with the TVOL (r = 0.080, P < 0.01). Non-iodized salt used in processed foods or diets when eating out had less effect on children's iodine nutrition status.

Conclusion: Iodized salt remains the primary source of daily iodine intake of SAC, and processed food has less effect on iodine nutrition. Therefore, for children, iodized salt should be a compulsory supplement in their routine diet.

Keywords: Dining place; Iodine-rich processed foods; Source of iodine; Urinary iodine.