Objective To investigate the dietary structure and iodine intake of residents in Tianjin, China, as well as the association between different dietary structures and iodine nutritional status.

Methods The food frequency questionnaire was used to investigate the food intake of residents in Tianjin, and urinary iodine concentration was measured in the laboratory. The subjects were categorized into different dietary patterns according to the intake of various types of food by cluster analysis to investigate the association between different dietary patterns and iodine nutritional status.

Results The intake of meat and eggs met the standard for recommended amount among both rural and urban residents, and the intake of cereals and potatoes, soybeans and nuts, and salt was higher than the recommended amount, while the intake of milk and dairy products, fruits, and oil was lower than the recommended amount; the intake of vegetables was lower than the recommended amount among rural residents, and the intake of aquatic foods was lower than the recommended amount among urban residents. The intake of the other types of food was in line with the recommended range. The median daily intake of iodine among urban residents (350.9 μg/d) was lower than that among rural residents (366.6 μg/d), and the median urinary iodine of urban residents (128.8 μg/L) was lower than that of rural residents (168.5 μg/L). The subjects were effectively categorized into three clusters, and the analysis of variance showed that there was a significant difference in urinary iodine concentration between the populations with different dietary patterns (P < 0.01), and the median urinary iodine values of the populations with the three dietary patterns were within the normal range.

Conclusion There is a need to adjust the dietary structure of residents in Tianjin, which is characterized by high intake of cereals and potatoes and salt and insufficient intake of vegetables, fruits, milk, and dairy products. Generally, the residents in Tianjin have proper dietary iodine intake and urinary iodine concentration and a good iodine nutritional status, and different dietary patterns have a certain impact on urinary iodine concentration.