The Association Mechanism between Dietary Patterns and Thyroid Nodule Risk in Women from Coastal Cities

Abstract

This study analyzed the association between dietary patterns and thyroid nodule risk in women in coastal cities. The results revealed that a high seafood-vegetable diet (average daily iodine intake of 352 ± 78 μg) significantly increased the risk of thyroid nodules (OR = 1.35, P = 0.002). The prevalence of urinary iodine concentrations >300 μg/L reached 36.7%, higher than the low iodine group (22.4%, P < 0.001). Antioxidant supplementation (vitamin C ≥ 80 mg/day, selenium ≥ 50 μg/day) reduced the prevalence (24.8% vs. 39.2%, P < 0.001), mitigating iodine-induced damage by reducing oxidative stress and enhancing Nrf2/HO-1 pathway activity. A predictive model combining urinary iodine and antioxidant nutrient scores achieved an accuracy of 78.3% (AUC = 0.783). This study proposed an iodine-antioxidant nutrient balance index, which provides a basis for thyroid health management in coastal women.