[Read on to see ANH comment following abstract]

Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis

Goran Bjelakovic, Dimitrinka Nikolova, Rosa G Simonetti, Christian Gluud

Lancet 2004; 364: 1219-28

The Cochrane Hepato-Biliary Group, Copenhagen Trial Unit, Centre for Clinical Intervention Research, Copenhagen University Hospital, H:S Rigshospitalet, Copenhagen, Denmark (G Bjelakovic MD, D Nikolova MA, R G Simonetti MD, C Gluud MD); Department of Internal Medicine--Gastroenterology and Hepatology, Medical Faculty, University of Nis, Nis, Serbia and Montenegro (G Bjelakovic MD); and Divisione di Medicina, Ospedale V Cervello, Palermo, Italy (R G Simonetti MD)

Correspondence to: Dr Goran Bjelakovic, Department of Internal Medicine--Gastroenterology and Hepatology, Medical Faculty, University of Nis, 18000 Nis, Serbia and Montenegro [email protected]

Summary

Background Oxidative stress can cause cancer. Our aim was to establish whether antioxidant supplements reduce the incidence of gastrointestinal cancer and mortality.

Methods With the Cochrane Collaboration methodology, we reviewed all randomised trials comparing antioxidant supplements with placebo for prevention of gastrointestinal cancers. We searched electronic databases and reference lists (February, 2003). Outcome measures were incidence of gastrointestinal cancers, overall mortality, and adverse effects. Outcomes were analysed with fixed-effect and random-effects model meta-analyses and were reported as relative risk with 95% CIs.

Findings We identified 14 randomised trials (n=170 525). Trial quality was generally high. Heterogeneity of results was low to moderate. Neither the fixed-effect (relative risk 0