Change in ankle-brachial index over time in a screened Japanese cohort - The Okinawa peripheral arterial disease study

Abstract

Background: The temporal change in ankle-brachial index (ABI) in the general population, especially in those aged <40 years, remains unclear. Methods and Results: ABIs of 23,673 individuals were measured in 1-day health checkups between 2003 and 2010. Among them, 1,117 participants aged 28–76 years (mean 53±9 years) whose ABI was measured at least twice within an interval of ≥4 years (mean: 4.9 years) were selected for this study. Baseline ABI was the lowest at age <40 years and increased with age. ABI significantly increased in participants aged <40 and 40–49 years, but not in participants aged 50–59 and ≥60 years. ABI increased in participants with borderline-low baseline ABI (0.9 <0.001) and normal baseline ABI (1.0≤ABI<1.2, 0.006; P=0.017). ABI decreased in participants with highnormal baseline ABI (1.2≤ABI<1.4, −0.04; P<0.001). Stepwise multivariate analysis revealed that ABI change was independently associated with baseline ABI (β=−0.566), height (β=0.162), body mass index (β=0.093), and sex (women, β=−0.08). Conclusions: ABI was lowest at age <40 years and increased with age. In participants aged <50 years, ABI significantly increased over the mean observation period of 4.9 years.