Introduction
Methods
Study design
Ethics statement
Phenotyping
Characteristic | Type 2 diabetes (n = 188) | Controls (n = 181) |
p value |
---|---|---|---|
Age (years) | 53.8 (35.0–70.7) | 38.5 (23.6–62.3) | <0.001 |
Sex (female [%]) | 81 (43.1) | 99 (54.7) | 0.03 |
Ethnicitya (%) | |||
Arab | 93 (43.1) | 113 (62.4) | |
South Asian | 74 (39.4) | 39 (21.5) | 0.002 |
Filipino | 14 (7.4) | 22 (12.2) | |
Other or mixed | 7 (3.7) | 7 (3.9) | |
BMI (kg/m2) | 29.5 (21.6–42.6) | 27.6 (21.7–39.1) | 0.004 |
Waist circumference (cm) | 101.0 (83.0–128.0) | 94.5 (74.0–116.1) | <0.001 |
Hypertension (%) | 103 (54.8%) | 27 (14.9%) | <0.001 |
Total cholesterol (mmol/l) | 4.95 (3.03–6.88) | 5.13 (3.74–6.61) | 0.11 |
HDL-cholesterol (mmol/l) | 1.13 (0.71–1.78) | 1.22 (0.77–1.90) | 0.02 |
LDL-cholesterol (mmol/l) | 2.79 (1.45–4.45) | 3.07 (1.55–4.67) | 0.02 |
Triacylglycerol (mmol/l) | 1.77 (0.76–4.69) | 1.38 (0.63–3.61) | 0.002 |
Creatinine (μmol/l) | 75.0 (48.4–112.6) | 69.0 (50.0–99.0) | 0.01 |
HbA1c (%) | 7.8 (5.6–11.5) | 5.5 (4.7–6.2) | <0.001 |
HbA1c (mmol/mol) | 62 (38–102) | 37 (28–44) | <0.001 |
Duration of diabetes (years) | 8.0 (1.0–31.7) | N/A | N/A |
Diabetes medication (%) | |||
Insulin | 39 (20.7) | 0 (0.0) | N/A |
Oral hypoglycaemic medication | |||
Metformin | 120 (63.8) | 0 (0.0) | N/A |
Sulfonylureas | 70 (37.2) | 0 (0.0) | N/A |
Thiazolidinediones | 6 (3.2) | 0 (0.0) | N/A |
Dipeptidyl peptidase-4 inhibitors | 19 (10.1) | 0 (0.0) | N/A |
Other | 15 (8) | 0 (0.0) | N/A |
Oral corticosteroids | 6 (3.2) | 1 (0.6) | 0.12 |
Metabolomics
Samplea
| Participants (n) | Metabolites (n) |
---|---|---|
Saliva | 328 | 581 |
Plasma | 359 | 720 |
Urine | 356 | 877 |
Total | 1,043 | 2,178 |
Statistical analysis
Results
Of 2,178 metabolite measures in saliva, plasma and urine, 94 were associated with diabetes at a Bonferroni level of significance
Metabolitea
| Superpathwayb
| Pathway | Saliva | Plasma | Urine | Reported association with a diabetes-related phenotyped
| |||
---|---|---|---|---|---|---|---|---|---|
βc
| Sig | β | Sig | β | Sig | ||||
Alanine | Amino acid | Alanine and aspartate metabolism | 0.196 | 0.110 | 0.541 | † | [24] | ||
N-acetyl-β-alanine | Amino acid | Alanine and aspartate metabolism | n.d. | 0.188 | 0.517 | † | Not previously reported | ||
Creatinine | Amino acid | Creatine metabolism | n.d. | −0.103 | −0.558 | † | [5] | ||
2-Hydroxybutyrate | Amino acid | Cysteine, methionine, SAM, taurine metabolism | 0.158 | 0.703 | † | 0.881 | † | ||
Cysteine | Amino acid | Cysteine, methionine, SAM, taurine metabolism | n.d. | 0.186 | 0.654 | † | |||
α-Ketobutyrate | Amino acid | Cysteine, methionine, SAM, taurine metabolism | −0.032 | 0.592 | † | n.d. | |||
Homocysteine | Amino acid | Cysteine, methionine, SAM, taurine metabolism | n.d. | n.d. | −0.639 | † | |||
Pyroglutamine | Amino acid | Glutamate metabolism | −0.305 | * | −0.471 | † | −0.331 | * | Not previously reported |
Glutamate | Amino acid | Glutamate metabolism | 0.119 | 0.209 | −0.478 | † | [43] | ||
5-Oxoproline | Amino acid | Glutathione metabolism | 0.241 | −0.235 | −0.753 | † | [41] | ||
β-Hydroxypyruvate | Amino acid | Glycine, serine and threonine metabolism | n.d. | 0.986 | † | 0.909 | † | Not previously reported | |
1-Methylhistidine | Amino acid | Histidine metabolism | n.d. | −0.593 | † | −0.598 | † | ||
Trans-urocanate | Amino acid | Histidine metabolism | 0.121 | n.d. | −0.533 | † | [46] | ||
Pipecolate | Amino acid | Lysine metabolism | 0.281 | 0.697 | † | 0.822 | † | ||
3-methoxytyrosine | Amino acid | Phenylalanine & tyrosine metabolism | n.d. | −0.526 | † | −0.279 | * | Not previously reported | |
4-Hydroxyphenylpyruvate | Amino acid | Phenylalanine & tyrosine metabolism | −0.219 | 0.490 | * | 0.581 | † | Not previously reported | |
Vanillylmandelate | Amino acid | Phenylalanine & tyrosine metabolism | n.d. | n.d. | −0.651 | † | Not previously reported | ||
Homovanillate | Amino acid | Phenylalanine & tyrosine metabolism | n.d. | n.d. | −0.523 | † | Not previously reported | ||
Phenylalanine | Amino acid | Phenylalanine & tyrosine metabolism | −0.006 | 0.109 | 0.573 | † | |||
Kynurenate | Amino acid | Tryptophan metabolism | n.d. | −0.322 | * | −0.531 | † | [47] | |
3-Hydroxyproline | Amino acid | Urea cycle; arginine-, proline-, metabolism | n.d. | n.d. | 0.647 | † | [48] | ||
Citrulline | Amino acid | Urea cycle; arginine-, proline-, metabolism | 0.148 | −0.588 | † | n.d. | |||
Homocitrulline | Amino acid | Urea cycle; arginine-, proline-, metabolism | n.d. | −0.207 | −0.541 | † | [5] | ||
Ornithine | Amino acid | Urea cycle; arginine-, proline-, metabolism | 0.077 | −0.378 | * | 0.525 | † | ||
Proline | Amino acid | Urea cycle; arginine-, proline-, metabolism | −0.010 | 0.196 | 0.654 | † | |||
3-Hydroxyisobutyrate | Amino acid | Valine, leucine and isoleucine metabolism | n.d. | 0.541 | † | 0.529 | † | ||
α-Hydroxyisovalerate | Amino acid | Valine, leucine and isoleucine metabolism | −0.022 | 0.066 | 0.683 | † | [51] | ||
Isobutyrylcarnitine | Amino acid | Valine, leucine and isoleucine metabolism | 0.203 | −0.067 | −0.532 | † | |||
Isoleucine | Amino acid | Valine, leucine and isoleucine metabolism | 0.090 | 0.179 | 0.589 | † | |||
Leucine | Amino acid | Valine, leucine and isoleucine metabolism | −0.071 | 0.126 | 0.613 | † | |||
Fructose | Carbohydrate | Fructose, mannose, galactose, starch, and sucrose metabolism | −0.172 | 0.878 | † | 0.177 | |||
Mannose | Carbohydrate | Fructose, mannose, galactose, starch, and sucrose metabolism | −0.091 | 1.136 | † | 0.731 | † | ||
1,5-AG | Carbohydrate | Glycolysis, gluconeogenesis, pyruvate metabolism | −0.998 | † | −1.287 | † | 0.161 | ||
1,3-Dihydroxyacetone | Carbohydrate | Glycolysis, gluconeogenesis, pyruvate metabolism | 0.140 | 0.631 | † | n.d. | Not previously reported | ||
Glucose | Carbohydrate | Glycolysis, gluconeogenesis, pyruvate metabolism | 0.159 | 1.158 | † | 0.913 | † | Diagnostic for diabetes | |
Lactate | Carbohydrate | Glycolysis, gluconeogenesis, pyruvate metabolism | 0.063 | 0.474 | * | 0.584 | † | ||
Pyruvate | Carbohydrate | Glycolysis, gluconeogenesis, pyruvate metabolism | 0.188 | 0.718 | † | −0.190 | |||
Arabitol | Carbohydrate | Nucleotide sugars, pentose metabolism | −0.274 | 0.095 | −0.546 | † | Not previously reported | ||
Gluconate | Carbohydrate | Nucleotide sugars, pentose metabolism | −0.249 | 0.949 | † | 0.185 | Not previously reported | ||
Ribose | Carbohydrate | Nucleotide sugars, pentose metabolism | 0.007 | n.d. | −0.603 | † | Not previously reported | ||
Xylonate | Carbohydrate | Nucleotide sugars, pentose metabolism | −0.112 | 0.079 | −0.507 | † | Not previously reported | ||
Threonate | Cofactors and vitamins | Ascorbate and aldarate metabolism | −0.118 | 0.094 | −0.539 | † | [41] | ||
2-Methylcitrate | Energy | Krebs cycle | n.d. | n.d. | −0.624 | † | [56] | ||
Malate | Energy | Krebs cycle | −0.103 | 0.303 | * | 0.715 | † | [4] | |
7-Ketodeoxycholate | Lipid | Bile acid metabolism | n.d. | n.d. | −0.549 | † | Not previously reported | ||
Adipate | Lipid | Fatty acid, dicarboxylate | n.d. | n.d. | −0.584 | † | [57] | ||
Ethanolamine | Lipid | Glycerolipid metabolism | −0.046 | n.d. | −0.546 | † | |||
Myo-inositol | Lipid | Inositol metabolism | −0.140 | 0.126 | 0.887 | † | |||
3-Hydroxybutyrate | Lipid | Ketone bodies | −0.065 | 0.271 | * | 0.917 | † | ||
Acetoacetate | Lipid | Ketone bodies | −0.053 | n.d. | 0.584 | † | [59] | ||
Heptanoate (7:0) | Lipid | Medium-chain fatty acid | −0.018 | −0.577 | † | n.d. | |||
N1-methyladenosine | Nucleotide | Purine metabolism, adenine containing | n.d. | −0.074 | −0.495 | † | Not previously reported | ||
Pro-hydroxy-pro | Peptide | Dipeptide | n.d. | −0.548 | † | −0.601 | † | [5] | |
Glycylglycine | Peptide | Dipeptide | −0.175 | n.d. | −0.621 | † | Not previously reported | ||
γ-Glutamylglutamine | Peptide | γ-Glutamyl | n.d. | −0.503 | † | n.d. | [60] | ||
γ-Glutamylleucine | Peptide | γ-Glutamyl | −0.093 | −0.026 | 0.551 | † | [5] | ||
Benzoate | Xenobiotics | Benzoate metabolism | −0.109 | −0.539 | † | −0.276 | * | [6] | |
Glycolate (hydroxyacetate) | Xenobiotics | Chemical | −0.232 | 0.086 | −0.478 | † | Not previously reported | ||
Metformin | Xenobiotics | Drug | 0.601 | † | 1.042 | † | 1.116 | † | Diabetes medication |
X-11333 | Unknown | Unknown | n.d. | n.d. | −0.603 | † | Not previously reported | ||
X-10593 | Unknown | Unknown | n.d. | n.d. | −0.554 | † | Not previously reported | ||
X-11315 | Unknown | Unknown | −0.555 | † | −0.820 | † | n.d. | [4] | |
X-11429 | Unknown | Unknown | n.d. | −0.824 | † | −0.186 | Not previously reported | ||
X-11540 | Unknown | Unknown | n.d. | −0.580 | † | n.d. | Not previously reported | ||
X-12170 | Unknown | Unknown | n.d. | n.d. | −0.539 | † | Not previously reported | ||
X-12253 | Unknown | Unknown | n.d. | n.d. | −0.557 | † | Not previously reported | ||
X-12682 | Unknown | Unknown | n.d. | n.d. | 0.583 | † | Not previously reported | ||
X-13431 | Unknown | Unknown | n.d. | −0.225 | −0.629 | † | Not previously reported | ||
X-13840 | Unknown | Unknown | n.d. | n.d. | −0.520 | † | Not previously reported | ||
X-14331 | Unknown | Unknown | n.d. | n.d. | 0.741 | † | Not previously reported | ||
X-14625 | Unknown | Unknown | n.d. | n.d. | 0.750 | † | Not previously reported | ||
X-14955 | Unknown | Unknown | n.d. | n.d. | 0.665 | † | Not previously reported | ||
X-15497 | Unknown | Unknown | −0.103 | 0.575 | † | n.d. | Not previously reported | ||
X-15503 | Unknown | Unknown | n.d. | −0.261 | * | −0.810 | † | Not previously reported | |
X-17299 | Unknown | Unknown | n.d. | −0.412 | * | −0.560 | † | Not previously reported | |
X-17323 | Unknown | Unknown | n.d. | n.d. | −0.483 | † | Not previously reported | ||
X-17629 | Unknown | Unknown | n.d. | −0.669 | † | n.d. | Not previously reported | ||
X-17676 | Unknown | Unknown | n.d. | n.d. | −0.884 | † | Not previously reported | ||
X-18221 | Unknown | Unknown | n.d. | 1.011 | † | n.d. | Not previously reported | ||
X-18475 | Unknown | Unknown | n.d. | n.d. | −0.627 | † | Not previously reported | ||
X-18887 | Unknown | Unknown | −0.023 | n.d. | −0.653 | † | Not previously reported | ||
X-19437 | Unknown | Unknown | −0.060 | −0.846 | † | 0.367 | * | Not previously reported |
Of the 94 diabetes associations, 65 were also identified as specifically associated with acute, short-term or long-term glycaemic control within the diabetes group
Timescale of dysregulation of glycaemic controla
| Metaboliteb
| β | −log(p) | GGM subnetwork | ||||
---|---|---|---|---|---|---|---|---|
Acute | Short term | Long term | Acute | Short term | Long term | |||
Acute | 3-Hydroxyisobutyrate (urine) | 0.696 | 0.558 | 0.106 | 5.3†
| 2.3 | 2.0 | Urinary ketone body |
Isoleucine (urine) | 0.706 | 0.388 | 0.078 | 5.4†
| 1.3 | 1.2 | Glycolysis–BCAAs | |
Leucine (urine) | 0.799 | 0.573 | 0.100 | 5.9†
| 2.0 | 1.6 | Glycolysis–BCAAs | |
α-Hydroxyisovalerate (urine) | 0.810 | 0.637 | 0.116 | 6.6†
| 2.6 | 2.1 | 1,5-AG | |
Pyruvate (plasma) | 0.919 | 0.993 | 0.213 | 8.5†
| 6.3†
| 6.6†
| Glycolysis–BCAAs | |
Lactate (urine) | 0.921 | 0.630 | 0.159 | 9.7†
| 2.9 | 4.2†
| Urinary ketone body | |
3-Hydroxybutyrate (urine) | 1.056 | 1.182 | 0.248 | 12.5†
| 9.1†
| 9.7†
| Urinary ketone body | |
2-Hydroxybutyrate (urine) | 1.165 | 1.138 | 0.211 | 15.4†
| 8.3†
| 6.8†
| Urinary ketone body | |
Acetoacetate (urine) | 1.299 | 1.241 | 0.244 | 18.8†
| 9.6†
| 8.8†
| 1,5-AG | |
Mannose (urine) | 1.285 | 1.372 | 0.289 | 20.1†
| 12.7†
| 13.1†
| 1,5-AG | |
β-Hydroxypyruvate (urine) | 1.622 | 1.507 | 0.301 | 35.1†
| 14.1†
| 13.6†
| 1,5-AG | |
Glucose (urine) | 1.864 | 1.574 | 0.342 | – | 17.4†
| 19.8†
| 1,5-AG | |
Short term | Glycolate (hydroxyacetate) (urine) | −0.266 | −0.828 | −0.130 | 1.1 | 4.9†
| 2.9 | Urinary ketone body |
3-Hydroxyisobutyrate (plasma) | 0.437 | 0.908 | 0.155 | 2.3 | 5.7†
| 3.9†
| Glycolysis–BCAAs | |
α-Ketobutyrate (plasma) | 0.607 | 1.050 | 0.185 | 4.2†
| 7.7†
| 5.5†
| Glycolysis–BCAAs | |
2-Hydroxybutyrate (plasma) | 0.575 | 1.217 | 0.189 | 3.7 | 10.2†
| 5.6†
| Glycolysis–BCAAs | |
1,5-AG (saliva) | −1.159 | −2.141 | −0.327 | 7.3†
| 18.6†
| 6.4†
| 1,5-AG | |
1,5-AG (plasma) | −1.222 | −2.632 | −0.432 | 16.3†
| – | 36.3†
| 1,5-AG | |
Long term | 1,3-Dihydroxyacetone (plasma) | 0.692 | 0.876 | 0.209 | 4.9†
| 5.0†
| 6.5†
| 1,5-AG |
Fructose (plasma) | 1.048 | 1.296 | 0.317 | 11.6†
| 11.3†
| 15.9†
| Carbohydrates | |
β-Hydroxypyruvate (plasma) | 1.263 | 1.561 | 0.351 | 16.2†
| 14.8†
| 18.0†
| 1,5-AG | |
Gluconate (plasma) | 1.081 | 1.290 | 0.338 | 13.2†
| 11.8†
| 18.9†
| Carbohydrates | |
Glucose (plasma) | 1.362 | 1.686 | 0.389 | 21.3†
| 20.7†
| 26.4†
| Carbohydrates | |
Mannose (plasma) | 1.282 | 1.743 | 0.389 | 18.9†
| 23.4†
| 27.5†
| Carbohydrates |