and the width of each diamond
represents the 95% confi dence interval.
The vertical dashed lines provide a visual
comparison of the pooled risk ratio with
the corresponding trial-specifi c risk ratios.
Tests for heterogeneity are as follows. For
any adenoma, Q = 5.13 ( P = 0.16) and I 2 =
41.5. For advanced lesion, Q = 1.27 ( P =
.74) and I 2 = 0.0. AFPPS = Aspirin/Folate
Polyp Prevention Study; APACC =
Association pour la Prevention par
l’Aspirine du Cancer Colorectal; CALGB =
Cancer and Leukemia Group B; CI = confi -
dence interval; ukCAP = United Kingdom
Colorectal Adenoma Prevention.