Relationship Between Iodine Nutritional Status and Low Handgrip Strength in a Northwestern Chinese Cohort: Construction of a Predictive Nomogram Model

Why It Matters

The model offers a low‑cost, objective tool for early identification of older adults at risk of muscle weakness, enabling timely interventions that could curb sarcopenia‑related morbidity and health‑care costs.

Key Takeaways

• Female sex reduces low grip strength risk (OR 0.34).
• Age ≥75 increases LGS odds nearly tenfold.
• Excess iodine linked to lower LGS odds.
• Smoking triples probability of low grip strength.
• Nomogram AUC 0.72 training, 0.66 validation.

Pulse Analysis

Grip strength is increasingly recognized as a vital sign of overall health, especially in aging populations where sarcopenia drives disability, falls, and mortality. While traditional risk factors such as age, nutrition, and chronic disease are well documented, trace elements like iodine have received far less attention. Iodine is essential for thyroid hormone production, which in turn regulates muscle metabolism and neuromuscular function. Emerging evidence links both iodine deficiency and excess to metabolic disturbances, suggesting a nuanced, possibly U‑shaped impact on muscle performance that warrants deeper exploration.

The Lanzhou cohort study leveraged a robust sample of 810 community‑dwelling adults, splitting the data into training and validation subsets to construct a predictive nomogram. By integrating urinary iodine concentration, systolic blood pressure, age, sex, height, and smoking status, the model achieved moderate discrimination (AUC 0.723 training, 0.662 validation) and solid calibration, outperforming generic risk scores. Notably, excess iodine (≥300 µg/L) emerged as a protective factor, particularly among participants with normal thyroid function, while smoking and advancing age dramatically heightened LGS odds. The nomogram’s simplicity—relying on readily available clinical measurements—makes it feasible for primary‑care settings in resource‑limited regions.

From a public‑health perspective, this tool could streamline community screening programs, allowing clinicians to prioritize high‑risk individuals for nutrition counseling, resistance training, or thyroid monitoring. However, the cross‑sectional design limits causal inference, and spot‑urine iodine may not reflect long‑term status. Future longitudinal studies across diverse geographic areas should validate the nomogram and dissect the biological pathways linking iodine to muscle strength. Such research could inform dietary guidelines and iodine fortification policies aimed at preserving functional independence in aging societies.