Table 1. β coefficients and corresponding p values from the meta-regression models.

Covariate	β coefficient	P value	N of studies
Source of data (tabular vs published paper)	0.144	0.28	20
Type of study (cross-sectional vs longitudinal)	0.164	0.213	20
Number of cases	−0.0003	0.018	19*
Number of participants	−0.000002	0.89	20
Percentage of Caucasian participants	0.142	0.316	20

*Number of cases not available for one study [60]. β –coefficient represents the change in log relative risk per unit increase in the relevant covariate. Each model includes each covariate as an explanatory variable and the log relative risk as the outcome variable.