Ethnicity and risk factors for change in the ankle-brachial index: the Multi-Ethnic Study of Atherosclerosis.
BACKGROUND
The aim of this study was to determine the risk factors for conversion from a normal to either a low or high ankle-brachial index (ABI).


METHODS
Participants in the Multi-Ethnic Study of Atherosclerosis who had two separate measurements of the ABI over a 3-year time period were assessed.


RESULTS
At baseline, the mean age was 62 years and 50% were women, 28% African American, 12% Chinese, 22% Hispanic and 38% non-Hispanic White. Of the 5514 participants with a baseline ABI between 0.90 and 1.40, 89 (1.6%) had an ABI < or = 0.90 ("low ABI group") and 71 (1.3%) had an ABI > or = 1.40 ("high ABI group") 3 years later. On multivariable analysis, the odds for having progressed into the low ABI group were significantly increased for higher baseline age, hypertension, diabetes, greater pack-years of cigarette smoking, and homocysteine levels. The odds for progression into the high ABI group were increased for male gender and higher body mass index. Compared with non-Hispanic Whites, African Americans had a significantly higher odds for progression to the low ABI group (odds ratio [OR]: 2.24, 95% confidence interval [CI]: 1.29-3.88) while having a reduced odds for progression to the high ABI group (OR: 0.50, 95% CI: 0.24-1.00). Neither Chinese nor Hispanic ethnicity was significantly associated with progression to either ABI group.


CONCLUSIONS
The risk factors for progression to a low or high ABI were distinct and African Americans were at increased risk for progression to a low ABI but at decreased risk for progression into the high ABI group.
Allison
Matthew A
MA
University of California San Diego, Department of Family and Preventive Medicine, 9500 Gilman Drive, Mailcode 0811, La Jolla, CA 92093-0811, USA. mallison@uscd.edu
Cushman
Mary
M
Solomon
Cam
C
Aboyans
Victor
V
McDermott
Mary M
MM
Goff
David C
DC
Criqui
Michael H
MH
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000842:Ankle / Q000098:blood supply*; D044466:Asian People / Q000706:statistics & numerical data; D050197:Atherosclerosis / Q000208:ethnology* / Q000209:etiology / Q000503:physiopathology; D044383:Black People / Q000706:statistics & numerical data*; D001794:Blood Pressure; D015992:Body Mass Index; D001916:Brachial Artery / Q000503:physiopathology*; D048909:Diabetes Complications / Q000208:ethnology / Q000209:etiology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D054624:Health Status Disparities; D006306:Health Surveys; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D020138:Hyperhomocysteinemia / Q000150:complications / Q000208:ethnology / Q000503:physiopathology; D006973:Hypertension / Q000150:complications / Q000209:etiology / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects; D013997:Time Factors; D044465:White People / Q000706:statistics & numerical data; D001741:Black or African American