Figure 2.

Reported coffee consumption associated with 24 h urine amounts of coffee components: (a) relationship between coffee metabolites measured in the 24 h urine samples and reported espresso intake for total caffeine metabolites (∑_caffeine); (b) total non-caffeine metabolites (∑_ncm). * = significant difference (p ≤ 0.05, Kruskal–Wallis test with Dunn’s multiple comparisons); ** = significant difference (p ≤ 0.01, Kruskal–Wallis test with Dunn’s multiple comparisons); *** = significant difference (p ≤ 0.001, Kruskal–Wallis test with Dunn’s multiple comparisons); **** = significant difference (p ≤ 0.0001, Kruskal–Wallis test with Dunn’s multiple comparisons).