title: Lower extremity arterial disease assessed by ankle-brachial index in a middle-aged population of African Americans and whites: the Atherosclerosis Risk in Communities (ARIC) Study.
abstract: BACKGROUND
  Lower extremity arterial disease (LEAD) is one of the most common manifestations of atherosclerosis. Its epidemiologic characteristics have not been well described, particularly in African Americans. Our purpose was to estimate the prevalence of LEAD and its associations with cardiovascular risk factors in a biracial population of men and women aged 45 to 64 years.
  
  
  METHODS
  We examined 15,173 African-American and white men and women who participated in the baseline examination (1987-1989) of the Atherosclerosis Risk in Communities (ARIC) Study. LEAD was defined by a resting ankle-brachial index (ABI), the ratio of ankle systolic blood pressure to brachial systolic pressure, of < or = 0.90. Cross-sectional analyses were used to determine the association of LEAD with cardiovascular risk factors.
  
  
  RESULTS
  The age-adjusted prevalence of ABI < or = 0.90 was 3.1% in African-American men, 4.4% in African-American women, 2.3% in white men, and 3.2% in white women. Cigarette smoking was the single most important risk factor for prevalent LEAD. The odds ratio estimate for LEAD in ever smokers versus never smokers was 6.6 (95% confidence interval [CI]=2.0-21.5) in African-American men, 2.3 (95% CI=1.5-3.5) in African-American women, 10.4 (95% CI=3.8-28.3) in white men, and 1.9 (95% CI=1.4-2.6) in white women, after adjustment for age, LDL cholesterol, hypertension, and diabetes. Prevalent LEAD was also associated with hypertension, diabetes, and higher concentrations of total cholesterol, triglycerides, LDL-cholesterol, and fibrinogen, and lower concentrations of HDL cholesterol, but the associations were not always significant across race/ethnic and gender groups. The associations of LEAD with plasma lipids were generally stronger in African Americans than whites.
  
  
  CONCLUSIONS
  The prevalence of LEAD appears to be higher in African Americans than whites. Elevations in traditional cardiovascular risk factors are associated with a higher prevalence of LEAD across race/ethnic and gender groups.
authors.affiliation: Division for Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3717, USA. zzheng@cdc.gov
authors.forename: Zhi-Jie
authors.initials: ZJ
authors.lastname: Zheng
authors.forename: Wayne D
authors.initials: WD
authors.lastname: Rosamond
authors.forename: Lloyd E
authors.initials: LE
authors.lastname: Chambless
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Nieto
authors.forename: Ralph W
authors.initials: RW
authors.lastname: Barnes
authors.forename: Richard G
authors.initials: RG
authors.lastname: Hutchinson
authors.forename: Herman A
authors.initials: HA
authors.lastname: Tyroler
authors.forename: Gerardo
authors.initials: G
authors.lastname: Heiss
mesh_terms: D001741:Black or African American; D000842:Ankle / Q000098:blood supply*; D050197:Atherosclerosis / Q000175:diagnosis* / Q000209:etiology; D001916:Brachial Artery; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D035002:Lower Extremity / Q000098:blood supply* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D044465:White People