Subclinical atherosclerosis and metabolic risk: role of body mass index and waist circumference

Abstract

Background: Carotid artery intima-media thickness (IMT) is greater in adults with elevated metabolic risk profiles. However, the influence of body mass index (BMI) or waist circumference (WC) on the relationship between IMT and metabolic risk is unclear.

Methods: Adults from the Bogalusa Heart Study were classified as normal weight, overweight, or obese and into WC categories (men, low <94 cm, moderate 94-101.9 cm, high ≥102 cm; women, low <80 cm, moderate 80-87.9 cm, high ≥88 cm). Elevated metabolic risk was defined by cardiovascular risk factor clustering (≥2 abnormal risk factors or insulin resistance (upper quartile of homeostasis model of insulin resistance). Carotid ultrasound measurements were obtained and mean IMT was calculated. General linear models compared IMT between elevated versus normal metabolic risk groups, adjusting for sex, age, race/ethnicity, and either BMI or WC category.

Results: Adults were 24-43 years of age (n = 991) and 41% had elevated metabolic risk (42% male, 28% African American, 38% obese). IMT (mm) was greater in adults with elevated metabolic risk (0.83 ± 0.007) versus normal risk (0.80 ± 0.006) whether adjusted by BMI or WC (both P < 0.0005). IMT was greater in adults with elevated compared to normal metabolic risk within normal-weight (0.84 ± 0.016 vs. 0.79 ± 0.008; P = 0.002), and obese adults (0.86 ± 0.009 vs. 0.80 ± 0.01; P = 0.03), but not significantly different between risk groups in overweight adults. Similar results were found when stratified by WC category.

Conclusion: Adults with elevated metabolic risk have greater IMT than those with normal risk in normal-weight, overweight, low WC, and high WC, but not significant for overweight or moderate WC categories.

Figures

FIG. 1.

Individual carotid segment thickness [mean ± standard error (SE)] between metabolic risk profiles adjusted for body mass index (BMI) group. Adjusted for age, sex, race, and BMI group (normal weight, overweight, and obese). (*) Significant difference between elevated and normal metabolic risk profile (P < 0.05). IMT, mean intima media thickness; CC, common carotid segment; IC, internal carotid segment; CB, carotid bulb segment.

FIG. 2.

Individual carotid segment thickness [mean ± standard error (SE)] between metabolic risk profiles adjusted for waist circumference (WC) group. Adjusted for age, sex, race, and WC group (sex-specific low, moderate, and high). (*) Significant difference between elevated and normal metabolic risk profile (P < 0.05). IMT, Mean intima media thickness; CC, common carotid segment; IC, internal carotid segment; CB, carotid bulb segment.

FIG. 3.

Mean intima media thickness (IMT) [mean ± standard error (SE)] between metabolic risk profiles within body mass index (BMI) groups. Adjusted for age, sex, and race. (*) Significant difference between elevated and normal metabolic risk profile (P < 0.05).

FIG. 4.

Mean intima media thickness (IMT) [mean ±standard error (SE)] between metabolic risk profiles within waist circumference (WC) groups. Adjusted for age, sex, and race. (*) Significant difference between elevated and normal metabolic risk profile (P < 0.05).