Background: The ankle-brachial index (ABI) is a predictor of cardiovascular events, mortality and functional status. Gender differences in ABI have been reported in some population studies. Differences in height might account for these observed gender differences, but findings are conflicting.
Objective: This study investigated the association between gender, height and ABI in the general population, independent of traditional cardiovascular disease (CVD) risk factors.
Methods: Participants ≥ 40 years from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 with ABI data, were included. A low ABI was defined as a value < 1.0 (including borderline values). Sample-weighted multivariable logistic regression modeling was performed with low ABI as the dependent variable and height and gender as primary predictor variables of interest. A backward elimination model selection technique was performed to identify significant covariates.
Results: There were 3,052 participants with ABI data (mean age 57, 51% female (1570 of 3052). The sample-weighted mean (±SE) ABI was 1.09 (±0.006) and 1.13 (±0.005) for females and males, respectively. Women were more likely to have a low ABI compared to men, 42% (659 of 1570) versus 28% (415 of 1482), respectively (p<0.0001). Female gender was associated with a low ABI (OR 1.34, [95% CI, 1.04-1.72]; p=0.025), independent of traditional CVD risk factors (see Figure). Age, diabetes, tobacco use, known CVD, BMI and black race were also associated with a low ABI (all p<0.003). Self-reported hypertension and non-HDL cholesterol levels, however, were not associated with a low ABI. An interaction between height and body mass index (BMI) was identified.
Conclusions: Female gender is associated with a low ABI in the general population. This association appears to be independent of height and other traditional CVD risk factors and warrants further investigation.