Additional file 8 of Maternal infection during pregnancy and the risk of childhood cancer: a systematic review and meta-analysis

Additional file 8: Table. S7: Subgroup analyses of observed associations by study-level characteristics. *P values for the subgroups are calculated using meta-regression, some P values not possible/not done due to few available studies for meta-regression, and some omitted due to collinearity. For exposure assessment, if studies report more than one method of assessment the most valid exposure assessment method is chosen. For outcome assessment, no registry means outcome assessed using methods other than registry or pathological confirmation. For confounder adjustment, basic means matching, or adjustment for basic characteristics e.g., age, sex, region; other factors include adjustments for comorbidities, genetic disorders, proxies for infection exposure such as sibship size, mode of delivery; similar factors include adjustments for other infections and antibiotics. Quality, high ≥ 28.4, cut off and low < 28.4 from the quality assessment tool. Abbreviations: ES estimate; UCI, upper confidence interval; LCI, lower confidence interval; Ref, reference value for subgroup analyses involving three categories.