Parity Is A Risk Factor For Hepatobiliary Neoplasm: A Meta-Analysis Of 16 Studies

Background: Conflicting results have been reported by studies assessing parity as a risk factor for hepatobiliary neoplasm. Methods: We conducted a meta-analysis of available epidemiologic studies to investigate the association of parity with hepatobiliary neoplasm and calculated dose-response trends using a linear model. Between-study heterogeneity was evaluated using Cochran's Q statistic and the I-2 index. Random effects meta-analysis was used to assess the summary relative risk (RR) per child and the 95% confidence interval (CI). Results: Eleven eligible studies including 2021 cases provided data for the meta-analysis. The summary RR of hepatobiliary neoplasm for the highest versus lowest parity number was 2.207 (95% CI = 1.397-3.488), with statistically significant heterogeneity (Q = 95.84, P = 0.000, I-2 = 82.3%). The summary RR of hepatobiliary neoplasm for parous versus nulliparous cases was 1.37 (95% CI = 1.159-1.624, I-2 = 43.8%, P = 0.001). The combined RR of hepatobiliary neoplasm for per live birth was 1.118 (95% CI = 1.032-1.211, I-2 = 77.0%, P = 0.000). We observed a positive association between giving birth to five or more children and hepatobiliary neoplasm risk, with an RR of 2.24 (95% CI = 1.472-3.411, I-2 = 55.6%, P = 0.005). Among the parity numbers considered, five or more was associated with the highest risk of hepatobiliary neoplasm. Elucidating the mechanism underlying this positive association requires further detailed investigation.