U-shaped association between serum selenium levels and insulin resistance in Mexican schoolchildren

Although selenium has been implicated in cardiometabolic diseases, its specific role in the pediatric population is not yet clearly established. The aim of this study was to analyze the linear and non-linear association between serum selenium levels and cardiometabolic markers in Mexican schoolchildren.

A cross-sectional study was conducted in 194 schoolchildren (6-10 years old) from primary schools. Anthropometric indicators, blood pressure, and cardiometabolic markers [Fasting Blood Glucose (FBG), insulin, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), Triglyceride-Glucose Index (TyG)] were evaluated. Serum selenium levels were determined by inductively coupled plasma mass spectrometry (ICP-MS). Quantile regression models and nonlinear relationships adjusted for nutritional status were used to assess associations between selenium levels and cardiometabolic markers.

The results showed that 39.6% of the participants had serum selenium levels below 6.0 µg/dL and 5.2% had levels above 12.9 µg/dL. Severe selenium deficiency was positively associated with higher insulin (β = 1.9; 95% CI: 0.7-3.1), HOMA-IR (β = 0.4; 95% CI: 0.1-0.7), TG (β = 17.0 mg/dL; 95% CI: 1.2-32.8), and TyG (β = 0.2; 95% CI: 0.1-0.4). A U-shaped relationship was found between HOMA-IR and serum selenium concentrations (p = 0.016).

Selenium deficiency was associated with adverse cardiometabolic markers in schoolchildren, regardless of nutritional status. Additionally, the observed U-shaped relationship suggests that both low and high selenium levels may influence insulin resistance in this population.