Table 3. Pearson's correlation coefficients among plasma amino acid concentrations and clinical variables.
| BMI | FPG | HbA1c | GA | 1,5-AG | C-peptide | Insulin | HOMA-IR | Leptin | Adiponectin | |
|---|---|---|---|---|---|---|---|---|---|---|
| Coefficient of correlation | ||||||||||
| Glucose related variables | ||||||||||
| FPG | −0.133 | — | 0.715*** | 0.778*** | −0.629*** | 0.154 | −0.094 | 0.321* | −0.126 | −0.017 |
| HbA1c | −0.06 | 0.715*** | — | 0.761*** | −0.758*** | 0.088 | −0.154 | 0.133 | −0.121 | −0.176 |
| Amino acids | ||||||||||
| Essential amino acids | ||||||||||
| Val | 0.109 | 0.221 | 0.401** | 0.104 | −0.240 | 0.275 | 0.228 | 0.309* | −0.084 | −0.535*** |
| Ile | 0.153 | 0.259 | 0.272 | 0.165 | −0.236 | 0.280* | 0.189 | 0.282* | −0.054 | −0.534*** |
| Leu | 0.128 | 0.251 | 0.289* | 0.116 | −0.163 | 0.238 | 0.252 | 0.330* | −0.137 | −0.468*** |
| His | 0.121 | −0.091 | −0.042 | −0.089 | 0.058 | 0.049 | 0.020 | 0.013 | −0.059 | −0.027 |
| Phe | 0.188 | −0.234 | −0.109 | −0.294* | 0.214 | 0.086 | 0.213 | 0.062 | −0.021 | −0.188 |
| Trp | 0.189 | −0.181 | 0.049 | −0.212 | 0.122 | 0.270 | 0.291* | 0.182 | 0.060 | −0.440*** |
| Met | 0.024 | −0.038 | 0.190 | −0.085 | −0.099 | 0.224 | 0.197 | 0.153 | −0.097 | −0.172 |
| Thr | 0.041 | −0.283* | −0.045 | −0.226 | 0.039 | −0.004 | 0.096 | −0.051 | −0.042 | −0.190 |
| Lys | −0.006 | −0.277* | 0.026 | −0.248 | 0.090 | 0.073 | 0.161 | 0.035 | −0.052 | −0.205 |
| Non-essential amino acids | ||||||||||
| Ser | −0.113 | −0.289* | −0.079 | −0.187 | 0.196 | −0.146 | 0.046 | −0.09 | −0.145 | 0.221 |
| Gly | −0.137 | −0.218 | −0.162 | −0.161 | 0.129 | −0.157 | −0.150 | −0.219 | −0.145 | 0.062 |
| Ala | 0.376** | 0.111 | 0.179 | −0.050 | −0.141 | 0.318* | 0.306* | 0.286* | 0.254 | −0.524*** |
| Tyr | 0.285* | −0.019 | 0.195 | −0.065 | −0.048 | 0.426** | 0.425** | 0.386** | 0.114 | −0.248 |
| Glu | 0.252 | 0.060 | 0.055 | −0.044 | −0.043 | 0.519*** | 0.564*** | 0.506*** | 0.066 | −0.381** |
| Pro | 0.301* | 0.243 | 0.325* | 0.132 | −0.333* | 0.317* | 0.237 | 0.337* | 0.279* | −0.248 |
| Gln | 0.039 | −0.336* | −0.074 | −0.168 | 0.048 | −0.112 | −0.060 | −0.194 | −0.047 | 0.028 |
| Cit | −0.259 | −0.064 | −0.055 | 0.127 | 0.085 | −0.154 | −0.252 | −0.236 | −0.142 | 0.220 |
| Arg | −0.033 | −0.194 | −0.028 | −0.149 | 0.103 | 0.082 | 0.081 | 0.019 | −0.087 | 0.082 |
| Orn | −0.056 | −0.153 | 0.033 | −0.113 | 0.110 | 0.119 | 0.101 | 0.041 | 0.047 | 0.030 |
| Asn | 0.151 | −0.266 | −0.111 | −0.253 | 0.129 | 0.006 | 0.099 | −0.043 | −0.018 | −0.146 |
| a-ABA | −0.129 | −0.025 | 0.165 | −0.003 | −0.031 | −0.093 | −0.053 | −0.095 | −0.202 | −0.224 |
| Amino acid index-1 | 0.342* | 0.229 | 0.280* | 0.071 | −0.203 | 0.546*** | 0.547*** | 0.569*** | 0.116 | −0.523*** |
| Amino acid index-2 | 0.304* | 0.324* | 0.421** | 0.164 | −0.298* | 0.447** | 0.387** | 0.483*** | 0.162 | −0.468*** |
Abbreviations: BMI, body mass index; FPG, fasting plasma glucose; GA, glycoalbumin; HbA1c, hemoglobin A1c; HOMA-IR, homeostasis model assessment of insulin resistance.
Pearson's product-moment correlation coefficients were used to evaluate the correlations between plasma amino acid and glucose- or insulin-related variables. Significant correlations are highlighted in bold letters and shown as *P<0.05, **P<0.01 and ***P<0.001.