3.4 Overall results of studies
All 12 studies were included in the pooled analysis. This included 2415 cases and 2545 controls. The pooled results (Figure 3) suggest that patients with DELC have an increased likelihood of having coronary artery disease. (OR= 4.61, 95% CI: 3.17 to 9.60). There was significant heterogeneity among studies (I2=83%, P<0.00001) whilst test for overall effect, Z, was 8.01 (p<0.00001). Ten of the 12 studies found a significant association between DELC and CAD. The two studies that found no significance association (14, 15) were poorer quality studies which both attributed their findings to age without any statistical analysis.