Table 2

Results of the quality assessment of cross sectional studies and case-control studies

Study reference2-151Methodological items2-150Method score(%)
123467891011121314151619202122232425Disagreements
Cross sectional studies
17 ++−++++++−+?+++++11,12,1314/1782
18 ++?+++NANA−++?++−++2,8,12,13,2311/1573
19 ++−+−+NANA+−+?+++++8,1211/1573
20 +?++++++−+−?++?++—12/1771
21 ++++−−+++−−?+++++612/1771
22 ++++−−++−−+?+++++6,1212/1771
23 ++++−+NANA+???+?+++12,13,2110/1567
24 +++++−+?−−−?+++++1,12,15,1911/1765
25 ++++−+++?−−?+++−+11,12,2411/1765
26 +?−+−+++−−−−+++++2,4,2311/1765
27 ++−+−−+++−−?+++++411/1765
28 ++++−−NANA?−−+++++?1,11,259/1560
29 ++++−−NANA−+−?−++++—9/1560
30 +++++++−++−?+−−−−11-13,23-2510/1759
31 +−++−+++−−−−+−−++29/1753
32 ++++−−++−−−?+++−?12,219/1753
33 ++++−−NANA−−−?−++++88/1553
34/35 ++?+−−+−?+−??+−++6,11,12,19,248/1747
36 ++++?+?−+−−?+−−?+2,7,218/1747
37 ++?+++++−−??+−−−−4,7,8,13,158/1747
38 +?−+−−++????++++−7,8,11,158/1747
39 ++++++NANA+?−?−−−??19,21,247/1547
40 ++?+−−NANA−−−?++−++2,19,257/1547
41 ++++−−NANA−−−?+−−++21,257/1547
42 ++?+−−NANA−?−?−++++2,47/1547
43 +++NANANA++−?−?+??−?23,246/1443
Case-control studies
44 +++++−+NANA+??+−?++++++2,3,13,15,1614/1974
45 +???+−−+−−+?+?++−?++?2,4,22,259/2143
46 ??+?+?+NANA−+−+?−++−−−?8,127/1937

  • ↵2-150 Enumeration of the quality items as in table 1. Items are scored as positive scores (+), negative (−), or unclear (insufficient information) (?).

  • ↵2-151 The studies are ranked according to their methods scores. Equally ranked studies are alphabetically ordered according to the first author's name.

  • NA=not applicable.