Table 1 Characteristics of case-control studies
Author, Year | PD/control | Country | Mean PD duration | Mean H&Y scale | Assessment of PD | Assessment of status of S-C and S-TG |
|---|---|---|---|---|---|---|
Becker 2008 [18] | 3637/3637 | UK | NA | NA | UKPD criteria/H&Y stage/UPDRS | Medical & Laboratories records |
Du 2012 [19] | 40/29 | USA | 4.2 | 1.5 | UPDRS | Laboratories records |
Guo 2015 [10] | 555/555 | China | 3.8 | 2.5 | UKPD criteria/H&Y stage/UPDRS | Laboratories records |
Huang 2007 [11] | 124/110 | USA | 4.2 | NA | UPDRS | Medical & Laboratories records |
Ikeda 2011 [20] | 119/120 | Japan | 6.9 | 3.2 | UKPD criteria | Laboratories records |
Kim 2017 [21] | 104/52 | Korea | 3.7 | 2.5 | H&Y stage/UPDRS | Laboratories records |
Kirbas 2014 [22] | 42/40 | Turkey | NA | NA | PDBBC/H&Y stage | Laboratories records |
Miyake 2010 [23] | 249/368 | Japan | NA | NA | UKPD criteria | Using diet history questionnaire (DHQ) |
Savica 2012 [24] | 196/196 | USA | NA | NA | H&Y stage/UPDRS | Laboratories records |
Scigliano 2006 [25] | 178/533 | Italy | 1.3 | ≈2 | UKPD criteria/H&Y stage/UPDRS | Laboratories records |
Vikdahl 2015 [26] | 84/336 | Sweden | NA | NA | UKPD criteria | Laboratories records |
Wei 2013 [27] | 110/130 | China | NA | 2.2 | Met the Calne’s criteria of clinically definitive PD | Laboratories records |
Zhang 2017 [28] | 91/70 | USA | NA | NA | MMSE | Laboratories records |