Treatment With B Vitamins and Incidence of Cancer in Patients With Previous Stroke or Transient Ischemic Attack: Results of a Randomized Placebo-Controlled Trial

• Published in: Stroke (1970) 2012-06, Vol.43 (6), p.1572-1577
• Main Authors: HANKEY, Graeme J, EIKELBOOM, John W, GOMMANS, John, SCHMIDT, Reinhold, QILONG YI, LEES, Kennedy R, CHEN, Christopher, XAVIER, Denis, NAVARRO, Jose C, RANAWAKA, Udaya K, UDDIN, Wasim, RICCI, Stefano
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cardiovascular system; Double-Blind Method; Female; Humans; Ischemic Attack, Transient - complications; Ischemic Attack, Transient - mortality; Male; Medical sciences; Neoplasms - mortality; Neoplasms - prevention & control; Neurology; Pharmacology. Drug treatments; Stroke - complications; Stroke - mortality; Vascular diseases and vascular malformations of the nervous system; Vasodilator agents. Cerebral vasodilators; Vitamin B Complex - administration & dosage
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/STROKEAHA.111.641613

To determine the effect of B vitamin treatment on the incidence of cancer among patients with stroke or transient ischemic attack. A total of 8164 patients with recent stroke or transient ischemic attack were randomly allocated to double-blind treatment with 1 tablet daily of placebo or B vitamins (2 mg folic acid, 25 mg vitamin B(6), 500 μg vitamin B(12)) and followed for a median of 3.4 years for any cancer as an adverse event. There was no significant difference in the incidence of any cancer among participants assigned B vitamins compared with placebo (4.04% versus 4.59%; risk ratio, 0.86; 95% CI, 0.70-1.07) and no difference in cancer mortality (2.35% versus 2.09%; risk ratio, 1.09; 0.81-1.46). Among 1899 patients with diabetes, the incidence of cancer was higher among participants assigned B vitamins compared with placebo (5.35% versus 3.28%; adjusted risk ratio, 2.21; 1.31-3.73), whereas among 6168 patients without diabetes, the incidence of cancer was lower among participants assigned B vitamins compared with placebo (3.66% versus 5.03%; adjusted risk ratio, 0.67; 0.51-0.87; P for interaction=0.0001). Daily administration of folic acid, vitamin B(6), and vitamin B(12) to 8164 patients with recent stroke or transient ischemic attack for a median of 3.4 years had no significant effect, compared with placebo, on cancer incidence or mortality. However, a post hoc subgroup analysis raises the hypothesis that folic acid treatment may increase the incidence of cancer among diabetics and reduce the incidence of cancer among nondiabetics with a history of stroke or transient ischemic attack.