Table 2.
Associations between PRAL score and diabetes-related intermediary traits in the baseline part of Inter99 study as well as means and medians for the individual quintiles
| Variable | Quintile 1 | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 | BetaModel 1 (95%CI) | P Model 1 | P Model 2 |
|---|---|---|---|---|---|---|---|---|
| PRAL range (mEq/d) | −92; −13 | −13; −3 | −3; 4 | 4; 12 | 12; 90 | |||
| HBA1C (%)a | 5.9 ± 0.5 | 5.8 ± 0.5 | 5.8 ± 0.5 | 5.8 ± 0.6 | 5.8 ± 0.5 | −0.0009 (−0.002; −5 × 10−5) | 0.04 | 0.01 |
| Plasma glucose (mmol/l) | ||||||||
| Fastinga | 5.6 ± 0.8 | 5.5 ± 0.8 | 5.5 ± 0.6 | 5.6 ± 0.9 | 5.5 ± 0.9 | − 0.0003 (− 0.002; 0.001) | 0.7 | 0.2 |
| 30 mina | 8.7 ± 2.0 | 8.7 ± 1.9 | 8.6 ± 1.9 | 8.6 ± 1.8 | 8.7 ± 1.8 | − 0.0009 (− 0.004; 0.002) | 0.6 | 0.2 |
| 120 min | 5.7 (4.8; 6.9) | 5.9 (4.9; 6.9) | 5.9 (4.9; 6.9) | 6.0 (5.0; 7.0) | 5.9 (5.0; 7.0) | 0.2 (0.1; 0.2) | 4 × 10−10 | 1 × 10−8 |
| Serum insulin (pmol/l) | ||||||||
| Fasting | 32 (22; 47) | 33 (23; 50) | 36 (24; 52) | 35 (25; 53) | 36 (25; 53) | 0.2 (0.09; 0.3) | 2 × 10−4 | 0.008 |
| 30 min | 239 (171; 334) | 234 (165; 346) | 243 (181; 349) | 257 (178; 376) | 257 (183; 368) | 0.07 (− 0.03; 0.2) | 0.2 | 0.8 |
| 120 min | 145 (86; 230) | 151 (96; 246) | 164 (103; 253) | 162 (103; 273) | 162 (95; 273) | 0.6 (0.4; 0.7) | 8 × 10−16 | 6 × 10−14 |
| Measures of beta cell function | ||||||||
| Insulinogenic index | 24.2 (16.5; 35.4) | 23.4 (15.9; 34.7) | 24.7 (17.2; 36.3) | 25.8 (17.2; 38.8) | 25.4 (17.2; 37.5) | 0.06 (−0.06; 0.2) | 0.3 | 0.8 |
| Corrected insulin response | 638 (392; 1051) | 602 (392; 1033) | 689 (413; 1107) | 691 (410; 1146) | 679 (413; 1094) | 0.09 (−0.04; 0.2) | 0.2 | 0.3 |
| Measures of insulin sensitivity | ||||||||
| HOMA-IR | 1.3 (0.89; 2.0) | 1.3 (0.89; 2.1) | 1.4 (0.94; 2.2) | 1.4 (0.98; 2.2) | 1.4 (0.97; 2.2) | 0.2 (0.07; 0.3) | 0.001 | 0.04 |
| ISIMatsuda | 8.4 (5.6; 11.7) | 8.1 (5.3; 11.9) | 7.8 (5.1; 11.1) | 7.5 (5.1; 10.9) | 7.6 (4.9; 10.8) | −0.2 (− 0.3; − 0.1) | 2 × 10−5 | 0.001 |
| BIGTT-Sia | 9.7 ± 4.1 | 9.4 ± 4.1 | 9.3 ± 4.0 | 9.0 ± 4.0 | 8.8 ± 4.0 | −0.02 (− 0.03; − 0.01) | 4 × 10−7 | 4 × 10−7 |
| Disposition Index | 304 (211; 447) | 291 (200; 410) | 298 (203; 419) | 297 (205; 412) | 306 (206; 415) | −0.2 (− 0.3; − 0.05) | 0.004 | 0.02 |
Data are from the Inter99 cohort (n = 5631) and are presented as mean ± standard deviation or median (inter quartile range) for each quintile of PRAL score as a description of the cohort. Effect sizes (95% confidence interval) are calculated using linear models with PRAL score as a continuous variable and are given as percentage increase for a one unit increase in PRAL score except for variables that have not been transformed by the natural logarithm in which case it is given as an increase per unit. The linear regression model 1 was adjusted for age, sex, smoking, physical activity and fat, energy and carbohydrate intake. The linear regression model 2 was further adjusted for BMI. BIGTT-Si was not adjusted for sex as this variable is included in the calculation of BIGTT-Si. Calculations of measures of beta cell function and insulin sensitivity were carried out as described in methods. Variables were transformed by the natural logarithm unless otherwise indicated by (a). Quintile values are raw data and are for descriptive purposes only