Institutional Review Board Statement
The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Regional Ethics Review Board of Stockholm (protocol code 01-314 and date of approval 2002-02-04; amendments 2007/801-32, 2009/796-32, 2009/1437-32, 2010/1041-32/1, and 2011/844-32, last approval date 2011-05-30).