Normal values for intima-media thickness of the common carotid artery - an update following a novel risk factor profiling

Abstract

Abstract. Background: There is a widely approved influence of novel risk factors like the body fat distribution and the associated metabolic syndrome, subclinical inflammation, insulin resistance and prediabetic disturbances in glucose metabolism on the progression of atherosclerosis. Former studies examining normal values for intima-media thickness (IMT) did not consider all of these new study results in detail. We therefore aimed to assess an update on age- and gender-specific normal values for IMT accounting for these novel risk factors. Patients and methods: We evaluated IMT by high-resolution ultrasound (13 MHz) on the far wall of the common carotid artery in 801 subjects without cardiovascular disease (428 women aged 46.2±12.9 years; 373 men aged 47.3±13.3 years). After precise evaluation and exclusion of 14 cardiovascular risk factors, 90% limits of IMT were determined by parametric statistics. Results: The reference limits of IMT according to the age classes 18-29, 30-39, 40-49 and 50-59 years were estimated as 0.47, 0.59, 0.67 and 0.70 mm in women and 0.47, 0.62, 0.72 and 0.80 mm in men. Conclusions: Age and gender-specific normal values for IMT are lower than reported in former studies after additionally accounting for novel cardiovascular risk factors. The still widely regarded upper IMT limit of 1 mm must be strictly regarded as obsolete.