Table 4. Description of the quality characteristics of the included and excluded studies in the Meta-Analysis of 5-HTTLPR polymorphisms and Post-traumatic Stress Disorder (PTSD).
| First author | Year | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | ||||||||||
| Repre sentative cases$ | Repre sentative controls# | Same diagnostic instrument | Trauma Exposed controls | Identical trauma experience | Ethnicity& | Blind assessment | Quality control Genotyping | HWE† testing | Confounders adjustment | Control for multiple comparisons | Psychiatric Comorbidity assessed | TQS ‡ | |||||||||||
| INCLUDED STUDIES | |||||||||||||||||||||||
| Lee [18] | 2005 | No | No | No | No | No | AS (100) | No | No | Yes | No | No | No | 2 | |||||||||
| Koenen [16] | 2009 | No | Yes | Yes | Yes | Yes | EA (90.7) Others (9.5) | No | Yes | No | Yes | No | No | 7 | |||||||||
| Mellman [21] | 2009 | No | Yes | Yes | Yes | No | AA (100) | No | Yes | No | Yes | Yes | Yes | 8 | |||||||||
| Xie [20] | 2009 | No | Yes | Yes | Yes | No | AA (53.5) EA (46.5) | No | No | Yes | Yes | No | Yes | 7 | |||||||||
| Grabe [19] | 2009 | No | Yes | Yes | Yes | No | Eu (100) | No | Ye | Yes | Yes | No | Yes | 8 | |||||||||
| Thakur [47] | 2009 | No | Yes | Yes | Yes | No | Caucasian (95.1) Other (4.9) | Yes | No | Yes | No | No | No | 5 | |||||||||
| Kolassa [17] | 2010 | No | Yes | Yes | Yes | No | Af (100) | No | No | Yes | No | No | No | 5 | |||||||||
| Saying [48] | 2010 | No | Yes | Yes | Yes | No | No | No | No | No | Yes | No | Yes | 5 | |||||||||
| Koenen [50] | 2011 | Yes | Yes | Yes | Yes | No | AA (79) Others (21) | No | Yes | No | Yes | No | Yes | 8 | |||||||||
| Morey [49] | 2011 | No | Yes | Yes | Yes | Yes | Caucasian (47.6) Others (52.4) | No | No | Yes | No | Yes | Yes | 8 | |||||||||
| Valente [46] | 2011 | No | No | Yes | Mix | No | No | No | No | Yes | No | No | Yes | 3 | |||||||||
| Wang [45] | 2011 | No | Yes | Yes | Yes | Yes | Caucasian (71.5) AA (24) Others (4.5) | Yes | Yes | Yes | Yes | Yes | Yes | 11 | |||||||||
| Xie [51] | 2012 | No | No | Yes | No | No | AA (46.3) EA (53.7) | No | No | Yes | Yes | No | Yes | 5 | |||||||||
| EXCLUDED STUDIES | |||||||||||||||||||||||
| King [52] | 2009 | No | No | Yes | Mix | No | AA, EA | No | No | No | Yes | No | No | 3 | |||||||||
| Handwerger [53] | 2010 | No | No | – | Yes | – | – | No | No | No | No | No | No | 1 | |||||||||
| King [44] | 2011 | No | No | – | Mix | No | – | No | No | No | No | No | No | 0 | |||||||||
Representativeness of cases included all eligible cases with outcome of interest over a defined period of time, all cases in a defined catchment area, all cases in a defined hospital or clinic, group of hospitals, health maintenance organization, or an appropriate sample of those cases (e.g. random sample).
Representativeness of controls assesses whether the control series used in the study is derived from the same population as the cases and essentially would have been cases had the outcome been present and included community and clinical controls within the same community or hospitalized population as cases.
If Yes, the % of the different ethnics groups are provided in brackets.AS: Asiatic. EA: Euro-American; AA: Afro-Americans; Af: African; Eu: Europeans.
HWE: Hardy-Weinberg Equilibrium; ‡TQS: Total Quality Score.