Homocysteine reduction not linked to improved CV, cancer outcomes
MedWire News: Meta-analysis findings suggest that lowering homocysteine levels with folic acid supplementation does not decrease the 5-year risk for cardiovascular (CV) events, cancer, or death.
"Although some benefit might emerge with even longer treatment and follow-up, the trial results give no reason to expect this," the study authors comment in the Archives of Internal Medicine.
Robert Clarke (University of Oxford, UK) and team analyzed the results of eight studies, with a total of 37,485 participants randomly allocated to receive folic acid (0.8 to 40.0 mg/day, n=18,723) or placebo/non-therapeutic folic acid dose (20.0 µg/day, n=18,762).
After a median follow-up period of 5 years, Clark and colleagues noted that 5125 participants died, 9326 had a major CV event, defined as major coronary event, stroke or revascularizations, and 3010 developed cancer.
During this period, a greater fall was observed in the homocysteine levels of participants taking folic acid than those taking placebo/non-therapeutic folic acid dose, with a median reduction of 27% versus 22% (p<0.001).
However, no significant increase in risk for cancer mortality, all-cause mortality, or CV outcomes was found among participants taking folic acid, with relative risks of 1.00-, 1.02-, 0.96- to 1.03, respectively, compared with that of participants taking placebo.
Clarke and team explain that although the failure of the analysis to reveal folic acid-related CV benefits "is disappointing", the absence of adverse events with folic acid supplementation is noteworthy in itself.
They conclude that given the frequent use of folic acid fortification in UK and US foods, the lack of such adverse outcomes "provides reassurance about the safety of population-wide folic-acid fortification."
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By Lauretta Ihonor