BMI mediates link between serum Mg level, insulin resistance in children

The negative association between serum magnesium (Mg) levels and insulin resistance (IR) among schoolchildren is partly mediated by the BMI z-score, suggests a study in Mexico. 

A group of researchers conducted this cross-sectional study to explore the relationship of serum Mg levels with the frequency of overweight and obesity, as well as cardiometabolic traits, in 189 schoolchildren (98 boys and 91 girls) between 6 and 12 years of age from Mexico City. 

The research team obtained anthropometrical data and measured biochemical parameters using enzymatic colorimetric assay. They also analysed serum Mg levels via inductively coupled plasma mass spectrometry (ICP-MS). Finally, the triglyceride-glucose (TyG) index was used as a surrogate marker to assess IR in children. 

Serum Mg level showed a negative relationship with overweight (odds ratio [OR], 0.377, 95 percent confidence interval [CI], 0.231–0.614; p<0.001) and obesity (OR, 0.345, 95 percent CI, 0.202–0.589; p<0.001). It also negatively correlated with BMI (β, −1.16; p<0.001), BMI z-score (β, −0.48; p < 0.001), and TyG index (β, −0.04; p=0.041). 

Additionally, a mediation analysis revealed that BMI z-score accounted for 60.5 percent of the negative association between serum Mg level and IR (Sobel test: z=2.761; p=0.005). 

“Our results [show] that BMI z-score mediates part of the negative association [between] serum Mg level and IR in Mexican schoolchildren,” the researchers said.