Table 5.
Quality assessment of studies included in the meta-analysis (Newcastle–Ottawa Scale for cohort studies)
| Selection | Comparability | Outcome | Total | Rating | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Author, year [Reference] | Representativeness of the exposed cohort | Selection of the non-exposed cohort | Ascertainment of exposure | Demonstration that outcome of interest was not present at start of study | Comparability of cohorts on basis of design or analysis | Assessment of outcome | Was follow-up long enough for outcomes to occur | Adequacy of follow-up of cohorts | Number of stars (max. 9) | 7–9=high; 4–6=moderate; 1–3=low |
| Africa | ||||||||||
| Abaasa, 2008 [20] | * | * | * | * | * | * | * | 7 | High | |
| Alemu, 2010 [23] | * | * | * | * | * | * | 6 | Moderate | ||
| Bastard, 2011 [26] | * | * | * | * | * | * | * | * | 8 | High |
| Biadgilign, 2012 [27] | * | * | * | * | ** | * | * | * | 9 | High |
| Bisson, 2008 [29] | * | * | * | * | * | * | * | * | 8 | High |
| Boyles, 2011 [30] | * | * | * | * | ** | * | * | * | 9 | High |
| Brinkhof, 2009 [32] | * | * | * | * | * | * | * | 7 | High | |
| Chalamilla, 2012 [33] | * | * | * | * | ** | * | * | 8 | High | |
| Chen, 2008 [34] | * | * | * | * | ** | * | * | 8 | High | |
| Chi, 2009 [35] | * | * | * | * | ** | * | * | 8 | High | |
| Chi, 2010 [36] | * | * | * | * | ** | * | * | * | 9 | High |
| Chu, 2010 [37] | * | * | * | * | * | * | * | * | 8 | High |
| Cornell, 2012 [39] | * | * | * | * | ** | * | * | * | 9 | High |
| De Beaudrap, 2008 [41] | * | * | * | * | * | * | * | 7 | High | |
| De Luca, 2012 [42] | * | * | * | * | ** | * | * | * | 9 | High |
| Desilva, 2009 [44] | * | * | * | * | ** | * | * | * | 9 | High |
| Fatti, 2010 [47] | * | * | * | * | * | * | * | * | 8 | High |
| Ford, 2010 [48] | * | * | * | * | * | * | * | * | 8 | High |
| Geng, 2010a [51] | * | * | * | * | * | * | * | * | 8 | High |
| Greig, 2012 [53] | * | * | * | * | ** | * | * | * | 9 | High |
| Hawkins, 2011 [54] | * | * | * | * | ** | * | * | 8 | High | |
| Hermans, 2012 [55] | * | * | * | * | * | * | * | * | 8 | High |
| Hoffman, 2011 [57] | * | * | * | * | ** | * | * | 8 | High | |
| Johannessen, 2008 [58] | * | * | * | * | * | * | * | * | 8 | High |
| Kassa, 2012 [60] | * | * | * | * | ** | * | * | * | 9 | High |
| Kouanda, 2012 [63] | * | * | * | * | ** | * | * | * | 9 | High |
| MacPherson, 2009 [65] | * | * | * | * | ** | * | * | * | 9 | High |
| Mageda, 2012 [66] | * | * | * | * | ** | * | * | 8 | High | |
| Maman, 2012b [68] | * | * | * | * | ** | * | * | * | 9 | High |
| Maman, 2012c [69] | * | * | * | * | ** | * | * | 8 | High | |
| Mutevedzi, 2011 [78] | * | * | * | * | ** | * | * | * | 9 | High |
| Negin, 2011 [80] | * | * | * | * | * | * | * | 7 | High | |
| Odafe, 2012 [82] | * | * | * | * | * | * | 6 | Moderate | ||
| Ojikutu, 2008 [83] | * | * | * | * | ** | * | * | * | 9 | High |
| Palombi, 2009 [84] | * | * | * | * | ** | * | * | * | 9 | High |
| Peterson, 2011 [87] | * | * | * | * | * | * | * | * | 8 | High |
| Poka-Mayap, 2013 [88] | * | * | * | * | ** | * | * | 8 | High | |
| Russell, 2010 [90] | * | * | * | * | * | * | * | * | 8 | High |
| Sieleunou, 2009 [92] | * | * | * | * | * | * | * | * | 8 | High |
| Somi, 2012 [94] | * | * | * | * | ** | * | * | 8 | High | |
| Toure, 2008 [98] | * | * | * | * | ** | * | * | * | 9 | High |
| Wandeler, 2012 [100] | * | * | * | * | * | * | * | 7 | High | |
| Wubshet, 2012 [102] | * | * | * | * | * | * | * | 7 | High | |
| Central Europe/East Europe | ||||||||||
| Tsertsvadze, 2011 [14] | * | * | * | * | ** | * | * | * | 9 | High |
| Latin America | ||||||||||
| Wolff, 2010 [104] | * | * | * | * | ** | * | * | * | 9 | High |
| Asia | ||||||||||
| Alvarez-Uria, 2013 [105] | * | * | * | * | ** | * | * | 8 | High | |
| Argemi, 2012 [106] | * | * | * | * | * | * | * | 7 | High | |
| Bastard, 2013 [107] | * | * | * | * | * | * | * | * | 8 | High |
| Chen, 2013 [109] | * | * | * | * | ** | * | * | * | 9 | High |
| Fregonese, 2012 [111] | * | * | * | * | ** | * | * | * | 9 | High |
| Rai, 2013 [114] | * | * | * | * | ** | * | * | * | 9 | High |
| Tran, 2013, Vietnam [118] | * | * | * | * | ** | * | * | 8 | High | |
| Van Griensven, 2011 [119] | * | * | * | * | * | * | * | * | 8 | High |
| Zhang, 2009 [121] | * | * | * | * | * | * | * | * | 8 | High |
*The study adequately met the criteria; 0–3 stars=low-quality rating, 4–6 moderate quality rating and 7–9 high-quality rating.