Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: In response to Drs Chae and Yun, we evaluated an interaction of aspirin and folic acid on the risk of adenomas during the second colonoscopic follow-up interval, using the statistical methods for intention-to-treat analysis described in our article. Participants randomized to 1 mg/d of folic acid had higher rates of colorectal adenomas than those randomized to placebo in each of the 3 aspirin treatment groups (placebo, 81 mg/d, and 325 mg/d); in addition, the folic acid group had higher rates of advanced lesions in the aspirin placebo and 325 mg/d of aspirin groups (Table). These estimates had larger variances than those in the first follow-up interval due to smaller numbers of participants with end point information. There was no significant interaction between aspirin and folic acid for any adenoma (unadjusted P = .97) or for any advanced lesion (unadjusted P = .27) in the second follow-up interval. Adjustment for age, sex, clinical center, length of follow-up, and number of lifetime adenomas at baseline did not substantially affect these findings.
Cole BF, Baron JA, Mott LA. Folic Acid and Prevention of Colorectal Adenomas—Reply. JAMA. 2007;298(12):1397. doi:10.1001/jama.298.12.1397-b