The effect of apolipoprotein E (apo E) common genotypes on fasting retinyl palmitate (RP) level was studied in 344 white individuals, of which 130 had intimal thickening of the carotid artery ("cases") and 214 were controls. In this sample the common apo E genotypes possessed a statistically significant effect on fasting RP level in cases, while in controls the effect observed was not statistically significant. It is suggested that the effect of apo E may be expressed at the level of remnant clearance particles. Additionally, in cases other traits interact with the apo E genotype to influence fasting RP level.