We conducted literature searches using
MEDLINE with the three limits “publication
date from 1 January 1950 to 31 December
2007,” “English language,” and
“human subjects” and combinations of
the medical subject headings “Diabetes
Mellitus” or “Diabetes Mellitus, Type 2,”
“Depression” or “Depressive Disorder,”
“Risk Factors,” and “Prospective Studies”
or “Longitudinal Studies.” The reference
lists of previous meta-analyses and selected
articles were screened.