of borderline significanceP = 0·06
In both the SR and POAF groups, the median plasma levels of 25(OH)D 2 , 25(OH)D 3 and total 25(OH)D were lower ( P < 0·05) on the third postoperative day compared with the preoperative values ( Table 2 ). Association of plasma 25-hydroxyvitamin D 2 and D 3 levels with postoperative atrial fibrillation The incidence of POAF was higher ( P < 0·05) in those with preoperative plasma levels above the median for 25(OH)D 2 (≥1·1 nmol/l) and total 25(OH)D (≥47·1 nmol/l) compared with those below the median, whereas the difference was of borderline significance ( P = 0·06) for 25(OH)D 3 (≥45·9 nmol/l) ( Fig. 1 ).