Samples |
For DAT1, they have included 11 study samples (10 published, one unpublished) in the meta-analysis [Cook et al., 1995; Waldman et al., 1998; Daly et al., 1999; Palmer et al., 1999; Holmes et al., 2000; Lunetta et al., 2000; Swanson et al., 2000; Barr et al., 2001; Curran et al., 2001 (two samples); and the CEDAR sample]. For DRD4, they have included 13 published samples and one unpublished sample in the meta-analysis (Rowe et al., 1998; Smalley et al., 1998; Swanson et al., 1998; Barr et al., 2000a; Faraone et al., 1999; Hawi et al., 2000; Holmes et al., 2000; Lunetta et al., 2000; Muglia et al., 2000; Sunohara et al., 2000; Tahir et al., 2000; Mill et al., 2001; and the CEDAR sample). For DRD5, they included 5 study samples (4 published, 1 unpublished) in the meta-analysis [Daly et al., 1999; Tahir et al., 2000; Barr et al., 2000b; Payton et al., 2001; and the CEDAR sample] |
Basic Result |
The pooled odds ratio estimate was 1.41 (95% CI 1.20-1.64, P=1.57*10-5), demonstrating positive association. For DRD5, data from five studies, with a total of 340 informative meioses, were combined yielding a pooled odds ratio of 1.57 (95% CI 1.25-1.96, P=8.28*10-5). Eleven studies examining DAT1, with a total of 824 informative meioses, yielded a non-significant pooled odds ratio estimate of 1.27 (95% CI 0.99-1.63, P=0.06). There was no support of heterogeneity between the studies. Overall, the meta-analyses support the involvement of the dopamine system genes in ADHD liability variation and suggest the need for studies examining interactions between these genes. |