Table 1.
Meta-analysis of the studies that compare the odds of placental P. falciparum infection among individuals with blood group A, B, AB or non-O vs those with blood type O
| Odds of Placental malaria (95% CI) | |||||||
|---|---|---|---|---|---|---|---|
| Parity | Placental malaria Type | Study | Sample size | A vs O | B vs O | AB vs O | Non-O vs O |
| Primiparae or Multiparae | Active or passive vs none | Adam et al. 2007 | 293 | 0.8 (0.44, 1.44) | 0.55 (0.27, 1.1) | 0.57 (0.21, 1.55) | 0.67 (0.41, 1.1) |
| Loscertales & Brabin, 2006 | 198 | 1.35 (0.63, 2.91) | 1.17 (0.59, 2.29) | 1.58 (0.28, 9.01) | 1.26 (0.71, 2.22) | ||
| Senga et al. 2007 | 647 | 1.32 (0.89, 1.96) | 1.22 (0.83, 1.79) | 3.68 (1.39, 9.74) | 1.35 (0.99, 1.85) | ||
| Bedu-Addo et al. 2014 | 827 | 1.16 (0.81, 1.66) | 1.62 (1.09, 2.39) | 1.77 (0.8, 3.91) | 1.38 (1.04, 1.85) | ||
| Adegnika et al. 2011 | 378 | 1.11 (0.39, 3.19) | 2.38 (0.91, 6.23) | 2.00 (0.23, 17.13) | 1.64 (0.75, 3.59) | ||
| Ukaga et al. 2007 | 586 | 0.72 (0.46, 1.13) | 0.68 (0.39, 1.18) | 0.21 (0.07, 0.62) | 0.61 (0.42, 0.89) | ||
| Adam et al. 2009 | 236 | – | – | – | 1.25 (0.91, 2.5) | ||
| Alim et al. 2015 | 126 | – | – | – | 1.11 (0.4, 3.33) | ||
| summary OR (95% CI) | 0.97 (0.75, 1.19) I2 = 8.2%, p = 0.007 | 1.02 (0.64, 1.40) I2 = 58.0%, p = 0.036 | 0.59 (0.02, 1.14) I2 = 32.9%, p = 0.189 |
1.01 (0.73, 1.29) I2 = 58.8%, p = 0.017 | |||
| Primiparae | Active vs uninfected | Adam et al. 2007 | 293 | 2/31 vs 0/51 | 0/24 vs 0/51 | 1/8 vs 0/51 | 3/50 vs 0/51 |
| Loscertales & Brabin, 2006 | 198 | 0.55 (0.15, 1.99) | 0.33 (0.10, 1.08) | – | 0.41 (0.16, 1.08) | ||
| Senga et al. 2007 | 647 | 0.31 (0.10, 0.97) | 0.79 (0.30, 2.06) | 0.93 (0.06, 15.62) | 0.54 (0.24, 1.21) | ||
| Bedu-Addo et al. 2014 | 827 | 2.59 (1.03, 6.50) | 1.56 (0.84, 2.91) | 4.53 (0.52, 39.74) | 1.90 (1.10, 3.28) | ||
| Adegnika et al. 2011 | 378 | 4.8 (0.73, 31.48) | 1.85 (0.16, 2.2) | - | 3.2 (0.55, 18.56) | ||
| summary OR (95% CI) | 0.41 (0.003, 0.82) I2 = 1.4%, p = 0.385 | 1.04 (0.3, 1.78) I2 = 68.9%, p = 0.022 |
1.42 (−5.81, 8.65) I2 = 0.0%, p = 0.738 |
0.75 (0.17, 1.34) I2 = 53.8%, p = 0.090 | |||
| Passive vs uninfected | Adam et al. 2007 | 293 | 0.46 (0.15, 1.41) | 0.31 (0.08, 1.20) | 0.87 (0.15, 5.00) | 0.44 (0.18, 1.08) | |
| Loscertales & Brabin, 2006 | 198 | 2.13 (0.42, 10.73) | 1.28 (0.28, 5.93) | – | 2.00 (0.55, 7.18) | ||
| Senga et al. 2007 | 647 | 1.28 (0.58, 2.81) | 1.24 (0.54, 2.83) | 2.48 (0.26, 23.38) | 1.32 (0.67, 2.52) | ||
| Bedu-Addo et al. 2014 | 827 | – | – | – | 2.23 (1.17, 4.26) | ||
| summary OR (95% CI) | 0.68 (0.13, 1.22) I2 = 0.0%, p = 0.390 | 0.59 (0.03 1.21) I2 = 14.4%, p = 0.331 | 0.94 (0.44, 3.31) I2 = 0.0%, p = 0.789 | 0.82 (0.08, 1.57) I2 = 42.5%, p = 0.176 | |||
| Active vs passive | Loscertales & Brabin, 2006 | 198 | 0.26 (0.05, 1.26) | 0.63 (0.27, 1.49) | 0.38 (0.04, 3.53) | 0.42 (0.2, 0.86) | |
| Senga et al. 2007 | 647 | 0.24 (0.08, 0.70) | 0.69 (0.31, 1.53) | 0.49 (0.05, 4.34) | 0.46 (0.23, 0.92) | ||
| Bedu-Addo et al. 2014 | 827 | – | – | – | 1.44 (0.56, 3.69) | ||
| summary OR (95% CI) | 0.24 (0.03, 0.52), I2 = 0.0%, p = 0.954 |
0.66 (0.23, 1.09), I2 = 0.0%, p = 0.892 | 0.42 (0.01, 1.78), I2 = 0.0%, p = 0.938 |
0.46 (0.23, 0.69) I2 = 0.0%, p = 0.458 |
|||
| Multiparae | Active vs uninfected | Adam et al. 2007 | 293 | 3.59 (0.66, 19. 69) | 2 (0.26, 15.12) | – | 2.37 (0.47, 11.91) |
| Loscertales & Brabin, 2006 | 198 | 1.55 (0.45, 5.34) | 2.07 (0.72, 5.93) | 2.07 (0.26, 16.27)) | 1.87 (0.77, 4.56) | ||
| Senga et al. 2007 | 647 | 1.78 (0.95, 3.35) | 1.54 (0.84, 2.86) | 5.27 (1.44, 19.32) | 1.78 (1.07, 2.96) | ||
| Bedu-Addo et al. 2014 | 827 | 0.21 (0.11, 0.40) | 0.36 (0.19, 0.66) | 0.36 (0.12, 1.07) | 0.29 (0.17, 0.48) | ||
| Adegnika et al. 2011 | 378 | 0.51 (0.11, 2.37) | 2.59 (0.91, 7.37) | 2.44 (0.27, 21.98) | 1.36 (0.55, 3.34) | ||
| summary OR (95% CI) | 0.76 (0.02, 1.54) I2 = 51.7%, p = 0.082 | 1.11 (0.15, 2.07) I2 = 52.2%, p = 0.079 | 0.38 (0.09, 0.86) I2 = 0.0%, p = 0.515 | 1.20 (0.22, 2.19) I2 = 72.1%, p = 0.006 | |||
| Passive vs uninfected | Adam et al. 2007 | 293 | 0.56 (0.19, 1.66) | 0.99 (0.37, 2.62) | 0.47 (0.10, 1.94) | 0.70 (0.32, 1.53) | |
| Loscertales & Brabin, 2006 | 198 | 3.22 (0.94, 11.05) | 2.93 (0.94, 9.13) | – | 2.76 (1.04, 7.34) | ||
| Senga et al. 2007 | 647 | 1.22 (0.58, 2.58) | 1.18 (0.58, 2.39) | 6.32 (1.71, 23.41) | 1.38 (0.78, 2.45) | ||
| summary OR (95% CI) | 0.82 (0.24, 1.41) I2 = 0.0%, p = 0.375 | 1.16 (0.46, 1.85) I2 = 0.0%, p = 0.668 | 1.01 (0.001, 2.77) I2 = 16.1%, p = 0.304 |
1.06 (0.38, 1.74) I2 = 31.8%, p = 0.231 | |||
| Active vs passive | Loscertales & Brabin, 2006 | 198 | 1.46 (0.6, 3.54) | 0.71 (0.21, 2.34) | – | 0.68 (0.24, 1.95) | |
| Senga et al. 2007 | 647 | 1.46 (0.6, 3.54) | 1.31 (0.56, 3.08) | – | 1.29 (0.64, 2.59) | ||
| Adam et al. 2007 | 293 | 5.18 (0.76, 21.87) | 2.9 (0.36, 26.39) | – | 1.21 (0.16, 9.23) | ||
| summary OR (95% CI) | 1.49 (0.46, 2.53) I2 = 0.0%, p = 0.790 | 0.97 (0.16, 1.78) I2 = 0.0%, p = 0.743 | – | 0.95 (0.31, 1.59) I2 = 0.0%, p = 0.650 | |||
Summary OR estimated using a meta-analysis technique applying fixed (I2 < 30%) or random (I2 ≥ 30%) effect model. Statistical significance of the heterogeneity of the studies was tested using the Cochran’s Q test at α = 5%