TABLE 9.
Outcome of the systematic search on folate and risk of colorectal cancer (sQ3b).
| LoE | Endpoints | RCTs | PCs/NCCs |
|---|---|---|---|
| LoE1. Standalone (main) | Incidence/recurrence of CRC | 1 |
34 P/S folate: 14 RBC folate: 2 a P/S UFA: 2 b Dietary intake of FA/folate: 23 c |
| LoE2. Standalone (surrogate) | Incidence/recurrence of colorectal adenomas | 7 d |
7 P/S folate: 2 RBC folate: 0 P/S UFA: 0 Dietary intake of FA/folate: 5 |
Abbreviations: CRC, colorectal cancer; FA, folic acid; LoE, line of evidence; NCC, nested case–control; P/S, plasma/serum; PC, prospective cohort; RBC, red blood cell; RCT, randomised controlled trial; UFA, Unmetabolised folic acid
a
The two studies assessing RBC also assessed P/S folate.
b
One study assessing UFA also assessed P/S folate.
c
Three studies assessing dietary intake of folate also assessed P/S folate.