Risk factors for CNS thrombosis. Leukemia risk group was the only risk factor for CNST by both univariate (P = .02) and multivariate (P = .04) analyses. Race (P = .13), age (P = .11), and BMI (P = .60) were not found to be statistically significant risk factors for CNST. CNST indicates central nervous system thrombosis; and BMI, body mass index.