It is crucial to provide adequate iodine nutrition to infants and toddlers for proper thyroid function and subsequent brain development. Infants are particularly vulnerable to iodine deficiency during the transition from a milk-based diet (breast milk and/or infant formula) to solid food. This study examines the current iodine levels of children during their first two years of life and investigates the association between these levels and feeding behaviors and the iodine status of their mothers in Shanghai, a city located in eastern China. A hospital-based cohort study was conducted to enroll mother–child pairs, where the child is aged 6–23 months, who visited community health service centers in the 16 districts of Shanghai, China. Data on socio-demographic factors and feeding behavior data were collected from the participants. The urinary iodine concentration (UIC) in both the young children and their mothers were analyzed. A total of 2282 mother–child pairs were included in this analysis. The median (p25–p75) UIC for lactating women, weaning women, and children were 121.3 μg/L (68.1–206.4 μg/L), 123.4 μg/L (58.4–227.2 μg/L), and 152.1 μg/L (75.8–268.3 μg/L), respectively. The UIC in children was found to be higher than that in their mothers (p < 0.001). Children who consumed less than 500 mL per day of formula milk in the last week had lower UICs compared with those who consumed 500 mL per day or more (p = 0.026). Furthermore, the children’s UIC was positively correlated with the maternal UIC (r_s = 0.285, p < 0.001). Multiple quantile regression analysis revealed a statistically significant positive association between maternal UIC and children’s UIC between the 0.1 and 0.9 quantiles (all p < 0.001). We found that the iodine status of infants and toddlers, as well as of mothers, was sufficient. However, a large minority of children and mothers may be at risk of iodine deficiency. Furthermore, no associations between children’s UIC and feeding behaviors were observed. Moreover, there was a positive correlation between the UIC of young children and their mothers.

Background: Noncommunicable diseases (NCDs) are a major global public health challenge and can be prevented and managed through a balanced, nutrient-rich diet. Food nutrition labels play an important role in guiding healthier choices, particularly for individuals at risk of chronic health conditions. This study assessed awareness, understanding and use of nutrition labels among adults in Shanghai, China, and explored their associations with NCDs. Methods: A face-to-face structured questionnaire survey was conducted among 1503 adults in 2024. Data were collected on sociodemographic characteristics, self-reported chronic conditions (obesity, diabetes, hypertension, hyperlipidemia, hypercholesterolemia, cardiovascular and cerebrovascular diseases (CCVDs), and fatty liver disease), and awareness, understanding, and use of nutrition labels. Generalized linear regression models were applied to assess associations between label-related behaviors and chronic conditions. Results: Overall, 81.6% of participants were aware of labels, 15.0% reported understanding them, and 35.5% reported using them. Participants who were underweight or obese were less likely to be aware of labels compared to those with normal weight (73.8% and 72.9% vs. 83.5%). Individuals with fatty liver disease were less likely to understand labels compared to those without the condition (7.2% vs. 16.1%). Conversely, participants with three or more chronic conditions were more likely to use labels than those without any chronic conditions (46.1% vs. 34.4%). Conclusions: Among adults in Shanghai, nutrition label awareness was relatively high, while understanding and use of labels remained insufficient. Targeted nutrition education and the integration of nutrition labeling into chronic disease management strategies are needed to improve public health outcomes.