Table 2. Summary risk estimates of the association between ever parity and gastric cancer risk.

	No. of Study	SRR	95% CI	I2 (%)	Ph†	Ph‡
Overall	7	0.96	0.87–1.05	0	0.504
Subgroup analyses
Number of cases						0.383
≥250	3	0.96	0.85–1.08	15.1	0.317
<250	4	0.84	0.62–1.13	0	0.594
Follow-up years						0.974
≥10	2	0.90	0.87–1.05	42.4	0.176
<10	5	0.94	0.81–1.11	0	0.593
Geographic location						0.221
Europe	3	0.98	0.89–1.08	0.8	0.388
Asia	3	0.80	0.58–1.12	0	0.517
North America	1	0.76	0.44–1.31	N/A	N/A
Menopausal status						0.962
Pre-menopausal	1	0.83	0.65–1.05	N/A	N/A
Post-menopausal	3	0.83	0.61–1.13	66.7	0.029
Anatomic subsite						0.279
Cardia	2	0.81	0.61–1.07	1.2	0.314
Non-cardia	3	0.99	0.88–1.12	0	0.589
Adjustment for potential confounders and risk factors
Age						0.769
Yes	5	0.95	0.82–1.10	0	0.862
No	2	0.82	0.59–1.15	60.0	0.082
Cigarette smoking						0.974
Yes	5	0.95	0.81–1.11	0	0.593
No	2	0.90	0.72–1.12	42.4	0.176
Body mass index						0.617
Yes	4	0.97	0.82–1.14	0	0.827
No	3	0.85	0.68–1.08	44.3	0.146
Alcohol drinking						0.844
Yes	3	0.88	0.67–1.15	24.6	0.265
No	4	0.97	0.86–1.08	0	0.468
Socioeconomic status						0.340
Yes	5	0.97	0.87–1.07	3	0.397
No	2	0.81	0.58–1.12	0	0.774

CI, confidence interval; N/A, not available; SRR, summarized relative risk.

^†P-value for heterogeneity within each subgroup.

^‡P-value for heterogeneity between subgroups with meta-regression analysis.