Table 2.

Summary risk estimates of the associations between vitamin D level and prostate cancer mortality.

Study characteristics	No. of studies	HR	95% CI	I2 (%)	P value 1	P value 2
Studies of PCM	6	0.91	0.87–0.97	53.4	0.057
Country						0.294
Europe	4	0.88	0.81–0.95	57.9	0.068
USA	2	0.96	0.90–1.03	0	0.389
Time of vitamin D assessment						0.36
Postdiagnosis	2	0.84	0.58–1.21	89.1	0.002
Prediagnosis	4	0.91	0.88–0.95	0	0.675
Follow-up						0.055
Less than 10 years	1
More than 10 years	5	0.92	0.89–0.96	0	0.479
Studies of ACM	5	0.91	0.84–0.98	68.9	0.012
Country						0.295
Europe	3	0.87	0.79	68.5	0.042
USA	2	0.98	0.93–1.03	0	0.576
Time of vitamin D assessment						0.246
Postdiagnosis	2	0.83	0.66–1.04	71.5	0.061
Prediagnosis	3	0.94	0.89–0.98	53.9	0.114
Follow-up						0.246
Less than 10 years	2	0.83	0.66–1.04	71.5	0.061
More than 10 years	3	0.94	0.89–0.98	53.9	0.114

P value 1 for heterogeneity within each subgroup. P value 2 for heterogeneity between subgroups with meta-regression analysis.

ACM, all-cause mortality; CI, confidence interval; HR, summary hazard ratio; PCSM, prostate cancer-specific mortality.