No significant effect modification was noted for sex (male vs female) or age (<25 vs !25) for any of the infectious agents (P values > .10). A significant interaction effect with race (black vs white) was found for HSV-1 (P < .01) and for CMV (P = .03), suggesting that significant differences exist in these antibody effects between black and white cases. As seen in Hazard ratio expressed per 1 SD increase of each agent antibody level.