Glycated hemoglobin level is strongly related to the prevalence of carotid artery plaques with high echogenicity in nondiabetic individuals - The Tromso Study

Background-High levels of HbA(1c) have been associated with increased mortality and an increased risk of atherosclerosis assessed as carotid intima-media thickness or plaque prevalence. In the present population-based study, we examined the association between HbA(1c) and plaque prevalence with emphasis on plaque echogenicity in subjects not diagnosed with diabetes. Methods and Results-HbA(1c) measurements and ultrasonography of the carotid artery were performed in 5960 subjects ( 3026 women, 2934 men) 25 to 84 years of age. Plaque morphology was categorized into 4 groups from low echogenicity ( soft plaque) to strong echogenicity ( hard plaque). HbA(1c) was categorized into 5 groups: <5.0%, 5.0% to 5.4%, 5.5% to 5.9%, 6.0% to 6.4% and >6.4%. Carotid plaque prevalence increased with increasing HbA(1c) level (P for linear trend = 0.002). The OR for hard plaques versus no plaques was 5.8 in the highest HbA(1c) group (>6.4%) compared with subjects in the lowest group (<5.0%) after adjustment for several possible confounders. The risk of predominantly hard plaques was also significantly associated with HbA(1c) levels, although the ORs at each level were somewhat lower than for hard plaques. With respect to the risk of soft plaques versus no plaques, no statistically significant relationship with HbA(1c) levels was found. Conclusions-Metabolic changes reflected by HbA(1c) levels may contribute to the development of hard carotid artery plaques, even at modestly elevated levels.