The analysis revealed five independent risk factors for postoperative pneumonia after craniotomy (Table 3), as follows: smoking history (OR: 4.123 [1.619, 10.499], P=0.003), surgical duration (OR: 3.447[1.332, 8.919], P=0.011), postoperative albumin (OR: 3.525 [1.380, 9.002], P=0.008), unplanned re-operation (OR: 28.223[5.840, 136.406], P<0.001), and deep vein catheterization (OR: 5.766 [1.956, 16.996], P=0.001). This evidence concerns the gene ALB and pneumonia.