Table 2.

Subgroup analyses examining specific characteristics and factors related to vitamin D in studies incorporated in the meta-meta-analysis.

Analysis	Model	Number of Reports (n)	Effect Size (ES) (OR or RR)	95% CI	p Value	I 2	p Value	Intercept	Tau (t)	p Value
Vitamin D intake and cancer risk *
Total cancer	Fixed	7	0.99 **	0.97–1.01	0.300	0.00	0.983	0.37	0.72	0.506
Colorectal carcinoma	Random	6	0.89 **	0.83–0.96	0.002	79.4	<0.001	−2.11	−1.70	0.164
Lung cancer	Fixed	3	0.88 **	0.83–0.94	<0.001	0.00	0.817	−0.72	−0.59	0.658
RCTs ***	Fixed	8	0.99 **	0.97–1.01	0.320	0.00	0.988	0.49	1.35	0.227
Observational	Random	14	0.90 **	0.86–0.95	<0.001	68.43	<0.001	−1.09	−1.51	0.156
Serum 25 (OH)D levels and cancer risk *
Colorectal carcinoma	Fixed	4	0.65 **	0.60–0.70	<0.001	48.4	0.121	3.23	1.21	0.351
Lung cancer	Random	3	0.89 **	0.75–1.05	0.178	85.84	0.001	−4.32	−0.68	0.619
Vitamin D intake and cancer related mortality *
Total cancer	Fixed	7	0.89 ****	0.85–0.93	<0.001	0.00	0.929	0.77	0.98	0.372
RCTs ***	Fixed	7	0.89 ****	0.85–0.93	<0.001	0.00	0.929	0.77	0.98	0.372

OR odds ratio, ES effect size, RR risk ratio, N/R not reported, RCTs randomized controlled trials, N/A not available or missing data, CI confidence interval, * Meta-meta-analysis was not conducted for types of cancer with fewer than three reports ** OR, *** studies containing only RCTs were included, studies with a combination of other study types and RCTs were excluded, **** RR.