Alcohol abuse
The prevalence of alcohol abuse among IA patients was 13.3% (95% CI: 5.9% - 27.0%, z = -4.158, df = 2, τ2 = 0.57, I2 = 94.18). The prevalence of alcohol abuse among the normal controls was 4.3% (95% CI: 1.4%–12.2%, z = -5.370, df = 2, τ2 = 0.99, I2 = 98.8). Figure 1 demonstrates the results of three studies which compared the prevalence of alcohol abuse between patients with IA and their healthy counterparts. The proportion of patients with alcohol abuse was significantly higher in the IA group than in the control group (pooled OR = 3.05, 95% CI: 2.14-4.37, z = 6.12, P < 0.001). There was a moderate but non-significant degree of between-study heterogeneity (τ2 = 0.052; Q = 4.22, df = 2, P = 0.121, I2 = 52.6).