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Table 3 Summary of Kruskal-Wallis univariate analysis

From: Metabolic phenotyping reveals a reduction in the bioavailability of serotonin and kynurenine pathway metabolites in both the urine and serum of individuals living with Alzheimer’s disease

Metabolite p value (Kruskal-Wallis test) Adjusted p value (Holm) Dunn’s post hoc test p value
CTL-AD CTL-MCI MCI-AD
Urine—xanthurenic acid 0.0002 0.0015 0.0001 0.0016 0.1615
Urine—kynurenic acid 0.0009 0.0071 0.0005 0.0047 0.181
Urine—serotonin 0.0020 0.0137 0.0016 0.2724 0.0047
Urine—5-hydroxyindoleacetic acid 0.0059 0.0293 0.0020 0.0842 0.0517
Urine—tryptophan 0.0128 0.0514 0.0050 0.098 0.0748
Urine3-hydroxyanthranilic acid 0.0495 0.1484 NA NA NA
Urine3-hydroxykynurenine 0.4235 0.8470 NA NA NA
Urinekynurenine 0.8738 0.8738 NA NA NA
Urine—kynurenine/tryptophan ratio 0.0040 0.0242 0.0021 0.0138 0.1966
Serum—xanthurenic acid 0.0018 0.0339 0.0019 0.0260 0.2796
Serum—kynurenine 0.0019 0.0339 0.0006 0.0429 0.0286
Serum—serotonin 0.0037 0.0625 0.0016 0.0178 0.1035
Serum—tryptophan 0.0047 0.0756 0.0024 0.0150 0.1407
Serum—3-hydroxyanthranilic acid 0.0222 0.3326 NA NA NA
Serum—kynurenic acid 0.0222 0.3326 NA NA NA
Serum—3-hydroxykynurenine 0.0236 0.3326 NA NA NA
Serum—β-nicotinamide mononucleotide 0.0241 0.3326 NA NA NA
Serum—picolinic acid 0.0518 0.5701 NA NA NA
Serum—5-hydroxyindoleacetic acid 0.0991 0.9912 NA NA NA
Serum—nicotinic acid 0.1066 0.9912 NA NA NA
Serum—quinolinic acid 0.1828 1.0000 NA NA NA
Serum—NAD+ 0.2589 1.0000 NA NA NA
Serum—dopamine 0.3926 1.0000 NA NA NA
Serum—neopterin 0.4934 1.0000 NA NA NA
Serum—nicotinic riboside 0.6746 1.0000 NA NA NA
Serum citrulline 0.8351 1.0000 NA NA NA
Serum—indole-3-acetic acid 0.8518 1.0000 NA NA NA
Serum—kynurenine/tryptophan ratio 0.2507 1.0000 NA NA NA
  1. p values from Kruskal-Wallis and subsequent post hoc tests using the Holm test to correct for multiple testing. Metabolites with a Holm-adjusted p value of < 0.1 are highlighted in bold and underwent a post hoc Dunn’s test to observe differences between subgroups. Metabolites with a Holm-adjusted p value of > 0.1 did not undergo a post hoc Dunn’s test and are labelled accordingly with NA