Table 4. Modified Newcastle-Ottawa quality assessment scale for case-control studies included in the meta-analysis.
| Selection* | Exposure0 | ||||||||
| Included Studies | Adequacy of Case Definition | Representativeness of the Cases | Selection of Controls | Definition of Controls | Comparability• | Ascertainment of Exposure | Same Method of Ascertainment for Cases and Controls | Non- ResponseRate | Total No. of stars |
| Kutty et al,26 2010. | A* | A* | A* | A* | A* | A* | A* | C | 7 |
| Nath et al,281994 | A* | A* | B | A* | A** | A* | A* | C | 7 |
| Jayatilaka et al,27 2007 | B | A* | B | A* | A** | A* | A* | C | 6 |
| Shah et al,29 2000 | A* | A* | B | A* | A* | A* | A* | C | 6 |
| Lowe et al,32 2006 | A* | A* | A* | A* | A* | A* | A* | C | 7 |
| Dial et al,30 2005 | A* | A* | A* | A* | A* | A** | A* | C | 8 |
| Dial et al,33 2006 | B | A | A* | A | A* | A** | A* | C | 5 |
| Aseeri et al,34 2008 | A* | A* | B | A* | A** | E | B* | C | 6 |
| Dubberke et al,35 2007 | A* | B | B | A* | A** | A* | A* | C | 6 |
| Loo et al,36 2005 | A* | A* | B | A* | A* | E | A* | C | 5 |
| Sundram et al,37 2009 | A* | A* | B | A* | A* | A* | A* | C | 6 |
| Novell et al,45 2010 | A* | A* | B | A* | A** | A* | A* | C | 7 |
| Debast et al,31 2009 | A* | A* | B | A* | A* | A* | A* | C | 6 |
| Kuntz et al,50 2011 | A* | A* | A* | A* | A* | A* | A* | C | 7 |
| Manges et al,49 2010 | A* | A* | B | B | A* | A* | A* | C | 5 |
| Naggie et al,51 2011 | A* | A* | A* | A* | A* | C | A* | C | 6 |
| McFarland et al,54 2007 | B | A* | C | A* | A* | A* | A* | C | 6 |
| Modena et al,56 2005 | B | A* | B | A* | A** | A* | A* | C | 5 |
| Muto et al,57 2005 | B | A* | B | A* | A** | A* | A* | C | 6 |
| Yip, et al,58 2001 | B | A* | B | A* | A** | A* | A* | C | 6 |
| Dial et al,53 2008 | B | A* | B | A* | A* | A* | A* | C | 5 |
| Kazakova et al,55 2006 | A* | A* | B | A* | A** | D | A* | C | 6 |
Selection:
(1)Is this case definition adequate? A, yes, with independent validation; B, yes, eg record linkage or based on self reports C, no description.
(2) Representativeness of the cases: A, Consecutive or obviously representative series of cases; B, Potential for selection biases or not stated.
(3) Selection of controls: A, Community controls; B, Hospital controls; C, No description.
(4) Definition of controls: A, No history of disease; B, No description of source.
Comparability: Comparability of cases and controls on the basis of the design or analysis: A, study controls for co-morbidities; B, study controls for any additional factor (e.g., age and severity of illness).
Exposure:
Ascertainment of exposure: A, Secured records; B, Structured interview where blind to case/control status; C, Interview not blinded to case/control status; D, written self report or medical record only.
Same method of ascertainment for cases and controls; A, yes; B, no.
Non-response rate: A, Same for both groups; B, Non-respondents described; C, Rate different and no designation.