Table 3. Meta-analysis of Case-control Studies on the Risk of Prostate Cancer Tissues and Sera, Stratified by Region, Publication Calendar Period and HPV Type.

	Total				Tissue-based detection				Serum-based detection
	No. of studies	No. of cases	P for heterogeneity	OR a (95% CI b)	No. of studies	No. of cases	P for heterogeneity	OR (95% CI)	No. of studies	No. of cases	P for heterogeneity	OR (95% CI)
Total	34	4540	<0.001	1.32 (1.12–1.55)	26	1218	<0.001	1.79 (1.29–2.49)	10	3436	0.302	1.03 (0.95–1.12)
Region
North America	12	2543	0.883	1.01 (0.90–1.14)	6	225	0.632	0.98 (0.70–1.36)	6	2318	0.813	1.02 (0.90–1.15)
Europe	8	1057	0.075	1.11 (0.93–1.32)	7	258	0.180	1.95 (1.35–2.81)	2	850	0.665	0.94 (0.79–1.13)
Asia	8	473	0.162	2.82 (1.89–4.21)	8	473	0.162	2.82 (1.89–4.21)	0	0	NA	NA
Africa	1	205	NAc	NA	0	0	NA	NA	1	205	NA	NA
Latin America	3	161	0.119	5.76 (2.25–14.76)	3	161	0.119	5.76 (2.25–14.76)	0	0	NA	NA
Ocean	2	101	0.008	1.29 (0.25–6.80)	2	101	0.008	1.29 (0.25–6.80)	0	0	NA	NA
Mixed	0	0	NA	NA	0	0	NA	NA	1	63	NA	NA
Publication calendar period
1990–1999	12	494	0.029	1.37 (0.85–2.21)	11	447	0.018	1.38 (0.82–2.30)	2	110	0.257	0.71 (0.20–2.50)
2000–2015	22	4046	<0.001	1.34 (1.12–1.59)	15	771	0.036	2.13 (1.45–3.12)	8	3326	0.243	1.04 (0.96–1.12)
HPV Type
High-riskd	24	3525	0.006	1.19 (1.00–1.42)	17	819	<0.001	1.70 (1.03–2.82)	9	2820	0.383	1.06 (0.96–1.16)
Low-riske	5	331	0.534	0.75 (0.38–1.47)	5	331	0.534	0.75 (0.38–1.47)	1	51	NA	NA
Related to HPV16
Yes	24	4090	0.018	1.15 (0.96–1.36)	16	768	0.001	1.95 (1.06–3.57)	10	3436	0.424	1.05(0.96–1.16)
No	12	3157	0.283	1.10 (0.94–1.29)	8	409	0.066	1.75 (1.22–2.51)	5	2799	0.962	0.98 (0.84–1.16)
Related to HPV18
Yes	12	3181	0.284	1.02 (0.82–1.28)	8	433	0.094	1.82 (0.97–3.41)	5	2799	0.606	0.92 (0.73–1.17)
No	16	3318	0.149	1.08 (0.96–1.21)	12	570	0.054	1.60 (1.23–2.09)	5	2799	0.895	0.98 (0.87–1.11)

^aOR: Odds ratio.

^b95% CI: 95% confidence interval.

^cNA: Not available.

^dHigh-risk: HPV 16, 18, 31, 33, 35, 39, 45, 52, 58, 59 and 68.

^eLow-risk: HPV 6 and 11.