Between-study heterogeneity
Between-study heterogeneity ranged from 0 to 98%, and was statistically
significant (Q test, p <0.10) in 164 meta-analyses
(32%), of which the vast majority (83%) examined the risk of childhood
hematological malignancies (Supplementary Table 5). A total of 105
meta-analyses (21%) showed considerable heterogeneity
(I2=50-75%). Substantial heterogeneity
(I2>75%) was found in 29 associations
(6%) which examined different risk factors in relation to childhood
hematological malignancies, CNS tumors, neuroblastoma and testicular
cancer. To further assess the uncertainty of effect estimates, we
calculated the 95% prediction intervals, which included the null value
in most associations (n=388, 76%).