The Relationship Between Dysglycemia and Atherosclerosis in South Asian, Chinese, and European Individuals in Canada

OBJECTIVE: Raised glucose levels extending from normal into the diabetic range (dysglycemia) are an emerging risk factor for clinical cardiovascular events. The relationship between dysglycemia and atherosclerosis (AS) in the general population and in different ethnic groups remains controversial. RESEARCH DESIGN AND METHODS: Glucose tolerance, HbA1c, other metabolic risk factors for AS, and carotid mean maximal intimal media thickness were assessed in a random sample of 979 Canadians of South Asian, Chinese, and European descent. RESULTS: The age and sex-adjusted intimal medial thickness increased 0.026 mm for every 0.9% increase in HbA1c in all participants (P < 0.0001) and in those of South Asian (P = 0.018), Chinese (P = 0.002), and European (P < 0.0001) descent. This progressive curvilinear relationship was most apparent at HbA1c levels >5.7%. The HbA1c-AS relationship persisted after adjustment for ethnicity, age, sex, diabetes status, abdominal obesity, insulin resistance, insulin secretion, fasting free fatty acids, blood pressure, and/or dyslipidemia (P < 0.004). Both diabetes (P = 0.002) and HbA1c (P < 0.0001) were determinants of the intimal medial thickness when included in separate statistical models. When included together in a single model, HbA1c (P < 0.0001) but not diabetes (P = 0.6) was a significant determinant. CONCLUSIONS: The degree of AS is related to the level of HbA1c irrespective of diabetes status and independent of abdominal obesity and other markers of the metabolic syndrome. This progressive relationship between HbA1c and AS was observed within different ethnic groups.