CHI3L1 and amyotrophic lateral sclerosis: The results extracted from four studies were analyzed using a random-effects model to compare the levels of CSF CHI3L1 in 258 ALS patients and 213 ONDS patients (ALS-C pooled SMD, 0.75; 95% CI, 0.32 – 1.19; P = 0.017) (Fig. 6).