Age- and sex-related effects on ankle-brachial index in a screened cohort of Japanese: The Okinawa Peripheral Arterial Disease Study (OPADS)

Abstract

Aims: Age-related change of anklebrachial index (ABI) within the general population, especially <40 years, has not been determined in large population studies. We evaluated the value of the ABI by age- and sex-related differences in a screened cohort. Methods and results: The ABI was examined in 13,211 participants (aged 2189 years) in a health valuation programme. The mean ABI was lower in women than in men at all ages. The ABI was lowest at <40 years, and increased with age; the maximum was at 6069 years in both sexes. In participants <40 years, 186 (22%) of women and 108 (9.8%) of men had a borderline ABI (0.91.0). The prevalence of an ABI ≤0.9 in men increased with age, and sharply rose to 3.3% at ≥70 years. Conversely, women demonstrated a J-curve relationship, where the prevalence of an ABI ≤0.9 was lowest at 6069 years (0.2%), and increased at <40 (0.9%) and ≥70 years (1.6%). The prevalence of atherosclerotic risk factors was higher in participants with an ABI ≤0.9 than those with an ABI >0.9 in men, both ≤60 and >60 years, and in women >60 years. In women ≤60 years, however, the prevalence of atherosclerotic risk factors in participants with an ABI >0.9 was as small as those with an ABI ≤0.9. Conclusion: The ABI increased with age until 6069 years, and was lower in women than in men. It is unlikely that a low ABI in younger healthy women always indicate that existence of arterial stenosis. © The European Society of Cardiology 2012.