Statistical analysis
Categorical (i.e. gender and race) variables were presented as percentages and continuous variables as mean and standard deviation. Exploratory data analysis (i.e. box plots and histograms) was used to summarize the distributions of the study variables. The data were examined for possible outliers and the normality assumption was tested. Diagnostic plots were employed to assess the normality of the residuals, homoscedasticity and case influential statistics. Results were approximately normal.The linear mixed-effects model was used to examine the influence of varying levels of dietary magnesium intake on whole blood iMg