Skip to main content

Advertisement

Table 2 The subgroup analysis for relative risks of childhood asthma in cesarean section

From: The association between caesarean section and childhood asthma: an updated systematic review and meta-analysis

Variable Studies (Na) Sample (N) Heterogeneity RRb 95% CIc P value
I2 P-value
Year of publication (year) 2000–2004 8 680,637 0 0.603 1.134 1.090–1.180 < 0.001
2005–2009 11 1,937,507 73.652 < 0.001 1.256 1.115–1.415 < 0.001
2010–2014 11 581,723 0 0.823 1.191 1.145–1.239 < 0.001
2015–2018 7 1,866,897 64.631 0.009 1.234 1.089–1.397 < 0.001
Test for subgroup differences: Q = 5.189, df(Q) = 3, P = 0.158
Study design Cohort 32 5,049,603 70.899 < 0.001 1.198 1.144–1.255 < 0.001
Case–control 3 12,373 0 0.999 1.199 1.049–1.372 0.008
Cross-sectional 2 4788 0 0.943 1.401 1.154–1.702 0.001
Test for subgroup differences: Q = 2.367, df(Q) = 2, P = 0.306
Prospective/retrospective Prospective 15 1,716,415 49.38 0.016 1.242 1.135–1.360 < 0.001
Retrospective 22 3,350,349 70.176 < 0.001 1.195 1.132–1.261 < 0.001
Test for subgroup differences: Q = 0.523, df(Q) = 1, P = 0.470
Quality of studies High 33 4,931,946 70.57 < 0.001 1.167 1.148–1.187 < 0.001
Moderate 4 134,818 0 0.749 1.095 0.818–1.465 0.544
Test for subgroup differences: Q = 0.427, df(Q) = 1, P = 0.514
Continent USA 4 25,964 0 0.914 1.227 1.102–1.367 < 0.001
Europe 27 4,901,351 73.451 < 0.001 1.197 1.142–1.254 < 0.001
Asia 5 138,412 51.819 0.081 1.431 0.967–2.118 0.073
Oceania 1 1037 0 NA 0.92 0.320–2.647 0.877
Test for subgroup differences: Q = 1.182, df(Q) = 3, P = 0.757
Age of diagnosis (years) ≤ 10 20 726,194 22.466 0.177 1.182 1.135–1.231 < 0.001
> 10 4 2,097,090 80.450 0.002 1.274 1.045–1.555 0.017
Both 13 2,243,480 14.038 0.303 1.141 1.101–1.182 < 0.001
Test for subgroup differences: Q = 2.523, df(Q) = 2, P = 0.283
  1. aNumber
  2. bRelative risk
  3. cConfidence interval