Table 4. Overall effect estimates for prostate cancer and statin use according to study characteristics.

	No. of studies	Pooled estimate		Tests of heterogeneity			pinteraction	Tests of publication bias
		RR (95% CI)	p-value	Q value (d.f.)	p-value	I2 (%)		Begg's p	Egger's p
All studies	27	0.93 (0.87–0.99)	0.03†	145.30 (26)	<0.001	82		0.56∥	0.12
Study design							0.45§
Cohort	15	0.93 (0.87–1.01)	0.09†	88.60 (14)	<0.001	84		0.56∥	0.07
Case-control	12	0.87 (0.72–1.05)	0.15	56.64 (11)	<0.001	81		0.31∥	0.09
PSA testing							0.76§
Adjusted	6	0.91 (0.81–1.02)	0.13	14.87 (5)	0.011	66		>0.99∥	0.49
Not adjusted	21	0.93 (0.86–1.01)	0.11	121.23 (20)	<0.001	83		0.53∥	0.04
BMI and ALS							0.24§
Adjusted	11	0.88 (0.78–0.99)	0.04†	44.23 (10)	<0.001	77		0.54∥	0.22
Not adjusted	16	0.96 (0.88–1.04)	0.37	81.09 (15)	<0.001	81		0.56∥	0.12
Bonovas et al. [24] analysis							0.63§
Before	10	0.95 (0.82–1.11)	0.58	26.62 (9)	0.002	66		0.73∥	0.51
After	17	0.91 (0.84–0.99)	0.03†	118.62 (16)	<0.001	87		0.27∥	0.01
Results for long-term statin use	11	0.94 (0.84–1.05)	0.31	28.80 (10)	0.001	65	0.74§	0.28∥	0.17
Cohort studies	7	0.91 (0.81–1.02)	0.12	14.79 (6)	0.02	59		0.14∥	0.02
Case-control studies	4	0.97 (0.64–1.48)	0.92	9.75 (3)	0.02	69		0.33∥	0.49
Results for advanced prostate cancer	7	0.80 (0.70–0.90)*	<0.001†	8.98 (6)	0.17‡	33	0.25§	0.77∥	0.90
Cohort studies	5	0.85 (0.72–1.00)*	0.04†	7.75 (4)	0.10‡	48		0.81∥	0.62
Case-control studies	2	0.74 (0.62–0.88)*	0.001†	0.01 (1)	0.90‡	-		-	-

PSA, Prostate specific antigen; BMI, Body mass index; ALS, Adverse life style; RR, Relative risk; CI, Confidence interval; d.f., Degree of freedom.

^*Relative risk from fixed-effects model due to no heterogeneity among the studies;

^† P value representing significant inverse association between statin use and prostate cancer;

^‡Statistically significant for homogeneity;

^§Test of interaction was not statistically significant;

^∥Statistically significant for no publication bias.