Table 4.

Regression analysis of rs3129882 in Parkinson’s disease

Regression analysis	Co-effort	SE	95% CI	t	P
All (14 studies)
Methods	0.096	0.038	0.013-0.179	2.55	0.027*
Ethnicity	0.008	0.033	-0.064-0.080	0.25	0.808
Cons	-0.006	0.019	-0.047-0.035	-0.33	0.751
Adjusted R2=58.3%
Caucasians (7 studies)
Methods	0.096	0.033	0.011-0.181	2.91	0.033*
Cons	0.002	0.024	-0.059-0.064	0.09	0.930
Adjusted R2=71.2%
Other techniques (11 studies)
Ethics	0.007	0.030	-0.061-0.076	0.25	0.812
Cons	-0.005	0.017	-0.044-0.034	-0.30	0.768
Adjusted R2=-35.4%

The two covariates examined included the method used (categorical variables: GWAS and other techniques) and ethnicity (categorical variables: Chinese and Caucasian), which were analyzed using the random-effects meta-regression model including 14 studies. In sub-group analysis, 7/14 studies of the Caucasians population were used to evaluate the contribution of the method used to the heterogeneity, and 11/14 studies using techniques other than GWAS were applied to evaluate contribution of ethnicity. The co-effort represents the log odds ratios of the covariates, with 95% CIs applied to evaluate the impacts of the covariates.

^*P<0.05.

Abbreviations: Co-effort, regression coefficient; SE, standard error; 95% CI, 95% confidence interval; t, t-value, ratio of log relative risk to standard error; Cons, constant effect; R²=1-SSE/SST, the proportion of variance explained by the covariates.