Results
Literature search
The initial screening yielded 206 publications. After selection, a total of 34 studies (1 article
[26] reported results from two subcohorts) from 33 publications [14–17, 26–54] were included
in the meta-analysis. Among these studies, twelve, nineteen and thirteen studies reported the
effects of dietary intake of α-carotene, β-carotene, lycopene on PCa risk, respectively. Eleven,
thirteen and fifteen studies reported the effects of blood levels of α-carotene, β-carotene, lycopene
on PCa risk, respectively(Fig 1).