For continuous predictors the researchers' decided to use the same method for choosing an incremental value to use for calculating the OR, what was this method?

Table 2. The multivariate adjusted odds ratios for postoperative infection. Model One SD Model 1 Model 2 Model 3 Model 4 Model 5 Odds Odds Odds Ratio Odds Ratio 95%CI Odds Ratio 95%CI Ratio 95%CI Ratio 95%CI 95% 092 0,41-4,14 1.16 11.60 3.80 0.89 1.21 0.80 1.45 1.21 0.89 1,30 1.32 0.88 1.51 1.30 0.91 0.45-49 0.91-1.60 0.58-141 0.81 0.36-2.32 0.91-147 0.54-1.23 (ref.) 0.98-9.21 0.59-22.50 1.11-11.05 0.88-2.74 0.35-2.31 0.94-1.56 0.52-1.21 ret) 0.90-9.30 0.55-23.62 1.20-13.28 0.8B-2.84 Male Gender Age (years) BMI (kg/m) ASA1 (96) ASA2 (%) ASA3 (96) DM (%) Total operation time Log (blood loss) Surgical procedure (96) CRP (mg/dl) ADN ratio 047-4.46 0.88-166 0.557-1.39 Tel 0.75-16.41 0.30-25.47 1.35-20.69 0.79-3.29 289 3.52 2.75 301 3.66 3.50 1.55 0.95-1.85 0.56-1.38 Tref) 0.72-1655 031-29.15 1.37-2266 0.84-3.68 3.45 3.00 5.56 1.76 3.40 2.60 5.86 1.71 0.70-16.75 0.30-26.40 142-24.30 0.81-3.50 400 5.28 1.62 114.10 1.58 616.20 6.59 2.20 1.88-23.14 0.79-6.11 6.18 2.40 169-22,66" 0.82-700 2.83 2.74 0.70-11.52 077-9.76 2.54 3.32 0.60-10.80 0.88-12.50 2.86 3.21 3.60-1282 090-1224 0.93-243 1.52 3.50 0,20 0.86-2.67 4.64-53.37" 153 15.20 090-2.71 450-51.13 14.90 462-48.00 15.73 *p