Table 2. Summary risk estimates of the association between selenium intake and pancreatic cancer risk.

				Heterogeneity test
Subgroups	No. (cases)	No. studies	Risk estimate (95% CI)	I2 (%)	P-value
All studies	1424	6	0.659 (0.489–0.889)	47.6	0.089
Study design
Case–control	1013	3	0.618 (0.399–0.956)	59.1	0.087
Prospective	411	3	0.709 (0.435–1.155)	49.6	0.138
Geographic locations
America	1071	3	0.570 (0.357–0.909)	65.6	0.055
Europe	249	2	0.899 (0.607–1.331)	0.0	0.443