Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12

Hati2 mengkonsumsi suplemen asam folat dan vitamin B12

 

Dua penelitian dengan desain randomized controlled trials terhadap 6.837 pasien penyakit jantung iskemik dari tahun 1998-2005 yang dilakukan di Norwegia mendapatkan bahwa suplementasi dengan asam folat dan vitamin B12 meningkatkan risiko kanker (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.03-1.41; P = .02). Dan meningkatkan kematian (from any cause) (HR, 1.18; 95% CI, 1.04-1.33; P = .01). Ini terutama disebabkan peningkatan insiden kanker paru pada kelompok yang mendapatkan asam folat dan vitamin B12.

 

JAMA302(19):2119-2126, 18 November 2009. © 2009 to the American Medical Association.
Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12. Marta Ebbing, Kaare Harald Bønaa, Ottar Nygård, et al.

Context  Recently, concern has been raised about the safety of folic acid, particularly in relation to cancer risk.

Objective  To evaluate effects of treatment with B vitamins on cancer outcomes and all-cause mortality in 2 randomized controlled trials.

Design, Setting, and Participants  Combined analysis and extended follow-up of participants from 2 randomized, double-blind, placebo-controlled clinical trials (Norwegian Vitamin Trial and Western Norway B Vitamin Intervention Trial). A total of6837 patients with ischemic heart disease were treated with B vitamins or placebo between 1998 and 2005, and were followed up through December 31, 2007.

Interventions  Oral treatment with folic acid (0.8 mg/d) plus vitamin B₁₂ (0.4 mg/d) and vitamin B₆ (40 mg/d) (n = 1708);folic acid (0.8 mg/d) plus vitamin B₁₂ (0.4 mg/d) (n = 1703); vitamin B₆ alone (40 mg/d) (n = 1705); or placebo (n = 1721).

Main Outcome Measures  Cancer incidence, cancer mortality, and all-cause mortality.

Results  During study treatment, median serum folate concentration increased more than 6-fold among participants given folic acid. After a median 39 months of treatment and an additional 38 months of posttrial observational follow-up, 341 participants (10.0%) who received folic acid plus vitamin B₁₂ vs 288 participants (8.4%) who did not receive such treatment were diagnosed with cancer (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.03-1.41; P = .02). A total of 136 (4.0%) who received folic acid plus vitamin B₁₂ vs 100 (2.9%) who did not receive such treatment died from cancer (HR, 1.38; 95% CI, 1.07-1.79; P = .01). A total of 548 patients (16.1%) who received folic acid plus vitamin B₁₂ vs 473 (13.8%) who did not receive such treatment died from any cause (HR, 1.18; 95% CI, 1.04-1.33; P = .01). Results were mainly driven by increased lung cancer incidence in participants who received folic acid plus vitamin B₁₂. Vitamin B₆treatment was not associated with any significant effects.

Conclusion  Treatment with folic acid plus vitamin B₁₂ was associated with increased cancer outcomes and all-causemortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods.