Fig. 2
From: Assessment of CYP1A2 enzyme activity in relation to type-2 diabetes and habitual caffeine intake
Paraxanthine/caffeine ratios in type-2 diabetes patient and non-type-2 diabetes control groups. Boxplots represent paraxanthine/caffeine ratios corrected to an “ideal” time interval between last caffeine intake and saliva sampling of 6 h (box: 25th percentile, median and 75th percentile; whiskers = 10th to 90th percentiles; dots: individual data points outside of the whisker range). Statistics compared type-2 diabetes patient (n = 57) and non-type-2 diabetes control (n = 146) groups by independent samples t-test on square-rooted data (2-tailed; equal variances assumed). Statistical analysis with the non-parametric Mann-Whitney U-test on non-transformed corrected paraxanthine/caffeine ratios confirmed the robustness of the result: T2D vs. non-T2D: mean rank 120.93 vs. 94.61; exact sig. 2-tailed: p = 0.004)