Dietary beta-carotene Highest vs lowest 0.84 3 46%, 0.16 (0.50-1.39) Dietary retinol 5.5.9 Dietary vitamin C Heterogeneity Author, Year Number of studies Comparison RR (95%CI) (I2, p value)* 12 0.78 Xu, 2012 (1 nested case-control and 11 Highest vs lowest 59%, 0.005 (0.62-0.98) case-control studies) 5.5.11 Dietary vitamin E Heterogeneity Author, Year Number of studies Comparison RR (95%CI) (I2, p value)* 10 0.87 Xu, 2012 (1 nested case-control and 9 Highest vs lowest 55%, 0.017 (0.69-1.10) case-control studies) 5.5.10 Serum vitamin D Heterogeneity Author, Year Number of studies Comparison RR (95%CI) (I2, p Lee, 2011 9 Per 10 ng/mL 0.93 (0.87-0.98) 63%, 0.006
Dietary beta-carotene 3 Highest vs lowest Dietary retinol 0.84 (0.50-1.39) 46%, 0.16 5.5.9 Dietary vitamin C Author, Year Number of studies Comparison RR (95%CI) Heterogeneity (I2, p value)* Xu, 2012 12 (1 nested case-control and 11 case-control studies) Highest vs lowest 0.78 (0.62-0.98) 59%, 0.005 5.5.11 Dietary vitamin E Author, Year Number of studies Comparison RR (95%CI) Heterogeneity (I2, p value)* Xu, 2012 10 (1 nested case-control and 9 case-control studies) Highest vs lowest 0.87 (0.69-1.10) 55%, 0.017 5.5.10 Serum vitamin D Author, Year Number of studies Comparison RR (95%CI) Heterogeneity (I2, p Lee, 2011 9 Per 10 ng/mL 0.93 (0.87-0.98) 63%, 0.006