Data Abstraction
Three of the authors used a standardized protocol
and reporting form to independently abstract data on
characteristics of trial participants and study design, intervention
method and duration, and study outcomes.
Where unstated, ethnicity was assumed to be white if
the study was conducted in Europe, Australia, or New
Zealand; Asian if the study was conducted in Asia; and
black if the study was conducted in Africa. Differences
in duplicate data extraction among the primary reviewers
were resolved by discussion and, where necessary, by
obtaining additional input from a fourth author.