(A) Meta-analysis forest plot for rs684513 age of tobacco initiation (AOI) showing the individual betas (for each study), summary beta, individual number of subjects (n), summary n, and a summary P-value. Individual and summary betas are for the rs684513 G allele. (B) Meta-analysis forest plot for rs684513 age of first regular tobacco use (AOS) showing the individual betas (for each study), summary beta, individual number of subjects (n), summary n, and a summary P-value. Individual and summary betas are for the rs684513 G allele.