In Box 2 Reference [52] should be corrected to [22]. References [18-21] in the text should be corrected to [18-22]. The 6 successive references from [22] to [27] in the text should be corrected to [23] to [28]. Finally, the current reference [28] in the text should be corrected to [14].

Posted: 2006-11-28
John P A Ioannidis
jioannid@cc.uoi.gr
Professor and Chairman of the Department of Hygiene and Epidemiology
School of Medicine, University of Ioannina, Ioannina, Greece, and Adjunct Professor of Medicine at the School of Medicine, Tufts University, Boston, Massachusetts, United States of America
Competing Interests: no