Brief Article
Copyright ©2012 Baishideng Publishing Group Co.
World J Gastroenterol. Jan 21, 2012; 18(3): 279-284
Published online Jan 21, 2012. doi: 10.3748/wjg.v18.i3.279
Figure 3
Figure 3 Funnel plot of the meta-analysis. Apparently asymmetrical distribution was found in the period before 2000.