Abstract
We performed this meta-analysis of epidemiological studies to comprehensively assess the association between parity and gastric cancer risk, because previous studies have shown conflicting results regarding this topic. Relevant prospective studies were identified by searching the following databases: PubMed, EMBASE, and Web of Science, and random-effects models were used to estimate summary relative risks (SRRs) and 95% confidence intervals (CIs). Our search yielded 10 prospective cohort studies involving a total of 6624 gastric cancer cases and 5,559,695 non-cases. The SRRs for ever parity vs. nulliparous and highest vs. lowest parity number were 0.96 (95%CI = 0.87–1.05, I2 = 0%) and 1.03 (95%CI = 0.94–1.13, I2 = 0%), respectively. Additionally, the SRR for an increment of one live birth was 1.00 (95%CI = 0.97–1.03, I2 = 18.6%). These non-significant associations were observed in all subgroups as stratified by the number of gastric cases, follow-up years, geographic location, menopausal status, anatomic subsite of gastric cancer, and adjustment for potential confounders, as well as in sensitivity analyses. Our meta-analysis found no significant association between parity and gastric cancer risk. However, further studies should be conducted to validate our findings and could provide more detailed results by stratifying their findings by Lauren’s subtype, histology, and anatomic site, as well as fully adjusting for potential confounding factors.
Highlights
Increasing evidence has suggested that there are differences in risk factors associated with developing different Lauren’s subtypes of gastric cancer and gastric cancers located at different anatomic sites[24,25]
Our current meta-analysis included results from 10 prospective studies which enrolled a total of 6624 gastric cancer cases and 5,559,695 non-cases, and had sufficient statistical power to detect an association between parity and gastric cancer
Two independent investigators (JC and third investigator (T-TG)) performed the study selection and exclusion procedures. Studies included in this analysis were required to satisfy the following criteria: (i) utilized a prospective study design; (ii) evaluated the association between parity and the risk for developing gastric cancer; (iii) presented estimates of relative risk (RR) or hazard ratio (HR) with 95% confidence intervals (CIs) or data necessary to calculate those parameters
Summary
Our sensitivity analysis of ever parity vs never parity performed by excluding one study at a time showed that the SRR for gastric cancer ranged from 0.93 (95%CI = 0.80–1.08; I2 = 0%) when Bahmanyar et al.[8] was excluded, to 0.96 (95%CI = 0.88–1.06; I2 = 0%), when Persson et al.[19] was excluded. Until recently, similar to the previous discussion of anatomical subtypes of gastric cancer, only a limited number of prospective studies have included a subgroup analysis stratified by menopausal status.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
