CST3 and glioblastoma: Moreover, reduced GBM risk was observed for high cystatin C levels when comparing tertile T3 with T1 (OR = 0.58, 95%CI = 0.46–0.72, P = 1.44 × 10−6), for older age at first sexual intercourse (OR = 0.95, 95%CI = 0.93–0.97, P = 3.51 × 10−5 per 1 year increase) and for attending (once a week or more often) a religious group, compared to attending any other group activity (OR = 0.48, 95%CI = 0.33–0.69, P = 6.53 × 10−5).