“This positive association was more apparent in men than in women, in adenocarcinoma [a type of cancer in the glands] patients, or in participants with equal or less than two years follow-up than those with longer duration of follow-up,” the researchers wrote.
The latest study follows a number of studies linking B12 supplementation to cancer risk.
A 2009 study published in The Journal of the American Medical Association found Folic acid and B12 supplementation was associated with a 21 percent increased risk for cancer.
To arrive at this conclusion, researchers analysed data from two studies that included almost 7,000 heart patients treated with B vitamin supplements or placebo for an average of three and one-half years between 1998 and 2005.