Changes in Dietary Magnesium Intake and Risk of Type 2 Diabetes Mellitus in Middle School Students: Using Data from the HEALTHY Study

Abstract

Background The HEALTHY Study was a multi-component, school-based intervention, designed to prevent type 2 diabetes mellitus (T2DM) in middle school students. Objectives We examined whether the difference in dietary magnesium intake, body mass index (BMI) percentile, and plasma glucose and insulin concentrations from 6th to 8th grade were related in the intervention schools and in the control schools that participated in the HEALTHY Study. Methods A total of 2,181 ethnically diverse students, from 11.3 to 13.7 years of age, with completed dietary records, BMI percentile, plasma glucose and insulin concentrations, at 6th and 8th grades were included. Dietary magnesium intake was self-reported using the Block Kids Food Frequency Questionnaire. A hierarchical multiple regression model was used to determine whether the difference in dietary magnesium intake, BMI percentile, plasma glucose and insulin concentrations from 6th to 8th grades were related, while adjusting for dietary calcium intake and total energy intake. Results The difference in dietary magnesium intake was significantly related to changes in BMI percentile from 6th to 8th grade in intervention and in control schools (Intervention: β = -0.07, 95% confidence interval [CI] = -0.58 to -0.02, P = 0.03, R2 [regression coefficient effect size] = 0.14, 95% CI for R2 = 0.10 to 0.17; Control: β = -0.08, 95% CI = -0.63 to -0.09, P = 0.01, R2 = 0.12, 95% CI for R2 = 0.08 to 0.15). The difference in dietary magnesium intake was not related to plasma glucose and insulin concentrations in intervention and in control schools. Conclusions We conclude that a multi-component intervention was associated with reduced risk in T2DM, and may be modulated, in part, by magnesium. The differences in dietary magnesium intake from 6th to 8th grade were negatively related to changes in BMI percentile among middle school students.