Oxidative modification of
LDL is believed to be a crucial step in
atherosclerosis. Thus,
antioxidant vitamins may have a role in the prevention of
coronary disease. We examined the cross-sectional association of serum
vitamin levels, the susceptibility of
LDL to
hemin-induced oxidation (lag phase to conjugated diene formation), and the
malondialdehyde-
LDL (MDA-
LDL) to native
LDL radioactivity binding ratio with carotid intima-media thickness (IMT), a measure of asymptomatic early
atherosclerosis. The participants in this observational study were 231 asymptomatic age-, sex-, race-, and field center-matched case-control pairs selected from the
Atherosclerosis Risk in Communities (ARIC) study cohort on the basis of B-mode carotid artery ultrasonograms obtained from 1986 through 1989. Cases exceeded the 90th percentile of IMT, and control subjects were below the 75th percentile of IMT for all arterial segments. Biochemical analyses were performed on fasting frozen (-70 degrees C) serum specimens collected from 1990 through 1992. In conditional logistic regression adjusting for age, blood storage time, total
cholesterol, and log-
triglyceride concentrations, serum
beta-cryptoxanthin and
lutein plus
zeaxanthin levels were inversely related to the extent of
atherosclerosis (odds ratio [OR] per 1-SD increase: 0.75, 95% confidence interval [CI]: 0.59-0.94; and OR per 1-SD increase: 0.76, 95% CI: 0.59-0.95, respectively). Increases in
alpha-carotene and
lycopene were associated with nonsignificantly lower odds of being a case, whereas
beta-carotene,
retinol, and
alpha-tocopherol were unrelated to IMT. Although not reaching statistical significance, the lag phase and
autoantibodies against MDA-
LDL were positively associated with asymptomatic
atherosclerosis. After adjustment for potential confounders, only the inverse association of
lutein plus
zeaxanthin with asymptomatic
atherosclerosis was maintained. This study supports a modest inverse association between circulating levels of some
carotenoids, particularly
lutein plus
zeaxanthin, and carotid IMT. These findings suggest that these
carotenoid compounds (regarded as
biomarkers of fruit and vegetable intake) may be important in early stages of
atherosclerosis.