Composition of lower extremity in relation to a high ankle-brachial index

Objective Clinical implications of a high ankle-brachial index (ABI) remain controversial. The involvement of atherosclerotic vascular changes as well as a close positive association with body weight has been postulated. We evaluated possible associations between a high ABI and atherosclerotic and anthropometric parameters. Methods Study participants were 407 community residents (68 +/- 8 years). Atherosclerosis was evaluated by arterial pulse wave velocity, carotid hypertrophy, and related plasma markers. Composition of the body trunk and lower extremity was evaluated by computed tomography. Results The frequency of high ABI individuals (>= 1.3) was 6.6%, and that was higher in men (70.4 vs. 37.4%, P<0.001). Characteristics included a significantly larger waist circumference (high ABI, 86 +/- 5; normal ABI, 82 +/- 9 cm, P = 0.033), lower high-density lipoprotein- cholesterol (60 +/- 16, 68 +/- 20 mg/dl, P = 0.042), and higher glucose (112 +/- 30, 104 +/- 20 mg/dl, P = 0.044), but not carotid hypertrophy (P = 0.315) and pulse wave velocity (P = 0.828). The high ABI individuals also had a significantly higher values for stature (162 +/- 8, 157 +/- 8 cm, P = 0.002), body weight (64 +/- 9, 56 +/- 10 kg, P<0.001), and visceral fat area (132 +/- 60, 100 +/- 64 cm(2), P = 0.012). Femoral muscle area (133 +/- 23, 109 +/- 23 cm(2), P<0.001) but not fat area (P = 0.301) was also larger in this group. Multiple regression analysis indicated that female sex (beta = -0.138, P = 0.019) and body weight (beta = 0.288, P<0.001) were independent determinant for ABI. However, after adding femoral muscle cross sectional area to the model, the latter became the only determinant of ABI (beta = 0.341, P<0.001). Conclusion Lower extremity composition is a strong determinant of ABI. A high ABI value might not be an adverse maker of atherosclerosis in the general population. J Hypertens 27: 167-173 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.