Table 4. Risk of bias of the included studies using the Cochrane Risk of Bias Tool.
| Reference | Risk factor | Random sequence generation | Allocation concealment | Blinding of participants and personnela | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other bias |
|---|---|---|---|---|---|---|---|---|
| Rampes et al., 1997, UK [21] | Alcohol | Low risk | Low risk | High risk | Low risk | Low risk | Low risk | Low risk |
| Sapir-Weise et al., 1999, Sweden [20] | Alcohol | Unclear | Low risk | Low risk | Low risk | Low risk | Low risk | Unclear |
| Bullock et al., 2002, USA [22] | Alcohol | Low risk | High risk | High risk | Low risk | High risk | Low risk | Unclear |
| Karst et al., 2002, Germany [19] | Alcohol | Unclear | Unclear | Low risk | Low risk | Unclear | Low risk | Unclear |
| Trumpler et al., 2003, Switzerland [18] | Alcohol | Low risk | Low risk | High risk | Low risk | Low risk | Low risk | High risk |
| Kunz et al., 2007, Germany [17] | Alcohol | Unclear | Unclear | High risk | Unclear | High risk | Low risk | High risk |
| Lee et al., 2015, Korea [16] | Alcohol | Low risk | High risk | Low risk | Low risk | Low risk | Low risk | Unclear |
| He et al., 1997, Norway [23,24] | Smoking | Low risk | High risk | Low risk | Unclear | Low risk | Low risk | Low risk |
| Waite & Clough, 1998, UK [25] | Smoking | Unclear | Unclear | Low risk | Unclear | High risk | Low risk | Low risk |
| White et al., 1998, UK [26] | Smoking | Low risk | Low risk | Low risk | Low risk | High risk | Low risk | Low risk |
| Georgiou et al., 1998, UK [27] | Smoking | Low risk | High risk | High risk | Low risk | High risk | Low risk | Low risk |
| Cai et al., 2000, Singapore [29] | Smoking | Low risk | High risk | Low risk | Low risk | High risk | Low risk | Low risk |
| Bier et al., 2002, USA [31] | Smoking | Low risk | High risk | Low risk | Low risk | High risk | High risk | Low risk |
| White et al., 2007, UK [28] | Smoking | Low risk | Low risk | High risk | High risk | High risk | Low risk | Unclear |
| Wu et al., 2007, Taiwan [33] | Smoking | Low risk | High risk | Unclear | Unclear | Low risk | Low risk | High risk |
| Yeh et al., 2009, Taiwan [34] | Smoking | Unclear | Unclear | Unclear | Unclear | Unclear | High risk | Low risk |
| Chae et al., 2010, Korea [35] | Smoking | Low risk | High risk | Unclear | Unclear | Unclear | Low risk | Low risk |
| Wing et al., 2010, Hong Kong [36] | Smoking | Low risk | High risk | Unclear | Unclear | High risk | Low risk | Low risk |
| Lambert et al., 2011, Singapore [30] | Smoking | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Fritz et al., 2013, USA [32] | Smoking | Low risk | Low risk | High risk | Low risk | High risk | Low risk | Low risk |
| Zhang et al., 2013, Australia [37] | Smoking | Low risk | Low risk | Low risk | Low risk | High risk | Low risk | Low risk |
| Baccetti et al., 2015, Italy [38] | Smoking | Low risk | High risk | Unclear | Unclear | High risk | Low risk | High risk |
| Macklin et al., 2006, USA [39] | Hypertension | Low risk | low risk | Low risk | Unclear | Low risk | Low risk | High risk |
| Flachskampf et al., 2007, Germany [48] | Hypertension | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk | Unclear |
| Yin et al., 2007, Korea [44] | Hypertension | Low risk | High risk | Low risk | Low risk | High risk | Low risk | Low risk |
| Zhang et al., 2008, USA [41] | Hypertension | Low risk | High risk | Low risk | Unclear | Low risk | Low risk | Unclear |
| Zhang et al., 2009, USA [42] | Hypertension | Low risk | High risk | High risk | Low risk | Low risk | Low risk | High risk |
| Kim et al., 2012, Korea [40] | Hypertension | Low risk | Low risk | Low risk | Low risk | High risk | Low risk | Unclear |
| Chen et al., 2013, China [46] | Hypertension | Unclear | Unclear | High risk | Unclear | Unclear | High risk | Unclear |
| Sriloy et al., 2015, India [49] | Hypertension | Unclear | Low risk | High risk | Unclear | High risk | High risk | High risk |
| Li et al., 2015, USA [43] | Hypertension | Low risk | High risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Liu et al., 2015, Korea [45] | Hypertension | Low risk | Low risk | High risk | Low risk | Low risk | Low risk | High risk |
| Lin et al., 2016, Taiwan [50] | Hypertension | Low risk | Low risk | Unclear | Unclear | Low risk | Low risk | High risk |
| Zhan et al., 2016, China [47] | Hypertension | Low risk | High risk | High risk | Unclear | Low risk | Low risk | Unclear |
| Richards & Marley, 1998, Australia [51] | Obesity | Low risk | High risk | High risk | Unclear | High risk | Low risk | Low risk |
| Mazzoni et al., 1999, Italy [52] | Obesity | Unclear | Unclear | High risk | Low risk | High risk | Low risk | Low risk |
| Wei & Liu, 2004, China [53] | Obesity | Unclear | Unclear | High risk | Unclear | Low risk | Unclear | Unclear |
| Hsu et al., 2005, Taiwan [54] | Obesity | Low risk | High risk | High risk | Unclear | Low risk | Low risk | Low risk |
| Elder et al., 2007, USA [55] | Obesity | Unclear | Unclear | High risk | Low risk | High risk | High risk | Low risk |
| Hsieh, 2007, Taiwan [56] | Obesity | Unclear | Unclear | Unclear | Unclear | High risk | Low risk | Unclear |
| Yeh & Yeh, 2008, Taiwan [57] | Obesity | Low risk | High risk | High risk | High risk | Low risk | Low risk | High risk |
| Nourshahi et al., 2009, Iran [58] | Obesity | Unclear | Unclear | High risk | Unclear | Low risk | Low risk | Unclear |
| Hsu et al., 2009, Taiwan [59] | Obesity | Low risk | High risk | Low risk | Unclear | High risk | Low risk | Low risk |
| Hsieh, 2010, Taiwan [60,61,65] | Obesity | Unclear | Unclear | Unclear | Unclear | High risk | High risk | High risk |
| Rerksuppaphol & Rerksuppaphol, 2011, Thailand [62] | Obesity | Low risk | High risk | High risk | High risk | Low risk | Low risk | Low risk |
| Rerksuppaphol, 2012, Thailand [63] | Obesity | Low risk | High risk | High risk | Unclear | High risk | Low risk | High risk |
| Lien et al., 2012, Taiwan [64] | Obesity | Low risk | High risk | Low risk | Unclear | High risk | Low risk | Low risk |
| Darbandi et al., 2012, Iran [66] | Obesity | Low risk | High risk | Unclear | Unclear | Low risk | Low risk | Low risk |
| Abdi et al., 2012, Iran [67] | Obesity | Unclear | Unclear | Unclear | Unclear | High risk | Low risk | Low risk |
| He et al., 2012, China [68] | Obesity | Unclear | Unclear | High risk | Unclear | Low risk | Low risk | High risk |
| Guo et al., 2014, China [69] | Obesity | Unclear | Unclear | High risk | Unclear | Low risk | Low risk | High risk |
| Wu et al., 2014, China [70] | Obesity | Low risk | High risk | Low risk | Unclear | Low risk | Low risk | High risk |
| Kim et al., 2014, Korea [71] | Obesity | Low risk | High risk | High risk | Unclear | High risk | Low risk | Low risk |
| Yeo et al., 2014, Korea [72] | Obesity | Low risk | Low risk | High risk | Unclear | High risk | Low risk | High risk |
| Schukro et al., 2014, Austria [73] | Obesity | Low risk | High risk | High risk | Unclear | High risk | Low risk | Low risk |
| Darbandi et al., 2014, Iran [74] | Obesity | Low risk | High risk | High risk | High risk | Low risk | Low risk | Low risk |
| Yeh et al., 2015, Taiwan [75] | Obesity | Low risk | Low risk | low risk | Unclear | High risk | Low risk | High risk |
| He et al., 2015, China [76] | Obesity | Low risk | High risk | High risk | Unclear | Low risk | Low risk | High risk |
| Jiao et al., 2015, China [77] | Obesity | Low risk | High risk | High risk | Unclear | Low risk | Unclear | Unclear |
aBlinding of participants and personnel: We only focus upon the blinding of participants as blinding the acupuncturists in acupuncture treatments is impossible due to methodological reasons.