Intima-media thickness in healthy subjects without risk factors for atherosclerosis

Background and objective: Ultrasound examination of the intima-media thickn ess (IMT) is a well accepted, highly reproducible method for the evaluation of early atherosclerosis. However, for the exact interpretation of these m easurements reference Va lues for IMT should be determined. The present wor k provides for the first time normal values for IMT of the common carotid a rtery and the arteries of the lower limbs (common femoral, superficial and popliteal arteries) in a German population of healthy subjects without risk factors. Subjects and methods: A total of 112 subjects (50 men, 62 women), aged 40 t o 70, were examined, according to the following inclusion criteria: no diab etes or marked elevation of postprandial plasma glucose; non-smokers; no hy pertension, obesity, dys/hyperlipidaemia or albuminuria; no history of coro nary heart disease, stroke and peripheral arterial occlusion. IMT was measu red and standardized by the method of Pignoli. Total cholesterol, triglycer ides, HDL-cholesterol, HbA(1c), plasma glucose (fasting and postprandial) a nd albuminuria were examined by routine methods. Results: The mean values of double measurements bilaterally in the distal p art of the common carotid artery in men were 0.79 (0.73...0.84) mm (40-54 y ea rs) and 0.87 (0.81...0.93) mm (55-70 years). In women the values were: - 0.70 (0.67...0.75) mm and 0.82 (0.75...0.90) mm, resp. In the group aged 4 0-54 years the men showed significantly higher IMT of all examined vessels in comparison to the women. In the group aged 55-70 years somewhat higher I MT of the common carotid artery and significantly higher IMT of the arterie s of the lower extremity were observed in men. In multivariate analysis age was found to be a significant determinant of I MT of all examined vessels. Conclusion: Intima-media thickening of the com mon carotid artery in men ag ed 40-70 years is to be accepted if a single measurement of IMT exceeds gre ater than or equal to 1 mm. For women, aged 40-54 years, IMT is defined as pathological if one I MT is above 0.85 mm, and for those aged 55-70 years i f IMT exceeds 1 mm.