Body mass index and peripheral artery disease

Background and aims: An independent association of body mass index (BMI) with atherosclerotic cardiovascular disease is somewhat controversial and may differ by vascular bed. Sex-specific risk factors for atherosclerosis may further modify these associations. Obesity and peripheral artery disease (PAD) are both more prevalent in women. We sought to determine the association between PAD and BMI using a very large population-based study. Methods: Self-referred individuals at > 20,000 US sites completed medical questionnaires including height and weight, and were evaluated by screening ankle brachial indices (ABI) for PAD (ABI < 0.9). Results: Among 3,250,350 individuals, the mean age was 63.1 +/- 10.5 years and 65.5% were women. The mean BMI was 27.7 +/- 5.8 kg/m(2). 27.8% of participants were obese (BMI >= 30 kg/m(2)) - 27.6% females, 28.1% males. Overweight individuals (BMI 25-29.9 kg/m(2)) exhibited the lowest prevalence of PAD. There was a J-shaped association of BMI with prevalent PAD. After adjustment for age and cardiovascular risk factors, underweight was associated with similarly increased odds of PAD (1.72 vs. 1.39, women and men, respectively). The association of obesity with PAD was predominant in women, with only a slight association of increasing BMI with PAD in men (OR - 2.98 vs. 1.37 for BMI >= 40 kg/m(2)). Conclusions: Our study suggests that increasing BMI is a robust independent risk factor for PAD only in women. This observation requires validation, but highlights the need for further research on sex-specific risk and mechanisms of atherosclerosis.