a nonsignificant trendP = 0.0009
The pooled effect on the log scale was an OR of 2.11 [95% CI (0.64, 6.90); P = 0.22], indicating a nonsignificant trend towards increased odds ( Fig. 5 ), with substantial heterogeneity ( I 2 = 90.9%; Q (1) = 10.98; P = 0.0009).