Segment-specific associations of carotid intima-media thickness with cardiovascular risk factors: the Coronary Artery Risk Development in Young Adults (CARDIA) study.

BACKGROUND AND PURPOSE: We propose to study possible differences in the associations between risk factors for cardiovascular disease (myocardial infarction and stroke) and carotid intima-media thickness (IMT) measurements made at 3 different levels of the carotid bifurcation. METHODS: We conducted a cross-sectional study of a cohort of whites and blacks of both genders with a mean age of 45 years. Traditional cardiovascular risk factors were determined in cohort members. Carotid IMT was measured from high-resolution B-mode ultrasound images at 3 levels: the common carotid artery, the carotid artery bulb (bulb), and the internal carotid artery. Associations with risk factors were evaluated by multivariate linear regression analyses. RESULTS: Of 3258 who underwent carotid IMT measurements, common carotid artery, bulb, and internal carotid artery IMT were measured at all 3 separate levels in 3023 (92.7%). A large proportion of the variability of common carotid artery IMT was explained by cardiovascular risk factors (26.8%) but less so for the bulb (11.2%) and internal carotid artery (8.0%). Carotid IMT was consistently associated with age, low-density lipoprotein cholesterol, smoking, and hypertension in all segments. Associations with fasting glucose and diastolic blood pressure were stronger for common carotid artery than for the other segments. Hypertension, diabetes, and current smoking had qualitatively stronger associations with bulb IMT and low-density lipoprotein cholesterol with internal carotid artery IMT. CONCLUSIONS: In our cohort of relatively young white and black men and women, a greater proportion of the variability in common carotid IMT can be explained by traditional cardiovascular risk factors than for the carotid artery bulb and internal carotid arteries.

Association of oxidative stress with mortality: the Beaver Dam Eye Study.

Epidemiological studies have shown that oxidative stress is associated with cardiovascular disease (CVD) and diabetes. However, the association of oxidative stress marker with non-CVD and CVD mortality has not been extensively evaluated. The association of baseline serum 8-isoprostane (8-ISO) with all-cause, non-CVD, and CVD mortality was examined in a random subset (n = 1,753) of a population-based study of 4,926 adults (99% non-Hispanic whites; 56% women) aged 43-86 years from the Beaver Dam Eye Study. Cause of death was ascertained by death certificate between 1987 and 2002. 8-ISO was measured by immunoassay. Cox proportional hazards regression analysis was used to estimate mortality hazard ratios (HRs) and 95% confidence intervals (CIs) by one 8-ISO standard deviation. During a median follow-up of 13.1 years, 590 (33.7%) participants died (290 CVD deaths). After adjusting for socio-demographics and CVD risk factors, 8-ISO was significantly associated with all-cause (HR = 1.1, 95% CI 1.01-1.2) and non-CVD (HR = 1.14, 95% CI 1.01-1.28) mortality but not with CVD mortality (HR = 1.06, 95% CI 0.93-1.2). When limited to participants with BMI < 25 kg/m2, individuals in the highest 8-ISO quartile had approximately 34 to 36% increased risk of all-cause, non-CVD, and CVD death compared to those at the lowest quartile. In contrast, 8-ISO was not significantly associated with mortality among those with BMI ≥ 25 kg/m2. These findings suggest that baseline serum 8-ISO, a marker of oxidative stress, is an independent risk factor of all-cause, non-CVD, and CVD mortality among a cohort of middle-aged adults with normal BMI.