title: A high normal ankle-brachial index is associated with proteinuria in a screened cohort of Japanese: the Okinawa Peripheral Arterial Disease Study.
abstract: OBJECTIVE
  We hypothesized that ankle-brachial index (ABI) increased with age as a result of arterial stiffness, and decreased when flow-limiting atherosclerotic stenosis occurred in the lower limbs. As arterial stiffness is associated with proteinuria, we investigated the relationship between ABI and prevalence of proteinuria.
  
  
  METHODS
  A cross-sectional study of ABI and proteinuria with 13,193 participants aged 21-89 years (53% women) from health checkups between July 2003 and March 2010 was conducted. ABI was measured using the automatic oscillometric method, and stratified into four groups: ABI ≤ 0.9 (low); 0.9 < ABI <1.0 (borderline low); 1.0 ≤ ABI <1.2 (normal); and 1.2 ≤ ABI <1.4 (high normal).
  
  
  RESULTS
  In participants with ABI at least 1.0, ABI was positively correlated with SBP, pulse pressure, and brachial-ankle pulse wave velocity. In participants with ABI less than 1.0, all indices were negatively correlated with ABI. The prevalence of proteinuria, defined as ≥ 1+ by dipstick, was significantly higher in low (23%) and high normal ABI (10%) compared with borderline low (6%) and normal ABI (7%). In participants at least 60 years, proteinuria was significantly associated with only low ABI [odds ratio (OR) 3.22, 95% confidence interval 1.34-7.41] compared with normal ABI before and after multivariable adjustment. In participants less than 60 years, adjusted OR for proteinuria was only significantly associated with high normal ABI (OR 1.32, 95% confidence interval 1.01-1.74).
  
  
  CONCLUSIONS
  High normal ABI in younger participants may be a result of arterial stiffness and associated with proteinuria.
authors.affiliation: aFaculty of Medicine, Department of Cardiovascular Medicine, Nephrology, and Neurology, University of the Ryukyus bOkinawa General Health Maintenance Association cDialysis Unit, University Hospital of the Ryukyus, Okinawa, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Ishida
authors.forename: Megumi
authors.initials: M
authors.lastname: Nakachi-Miyagi
authors.forename: Kozen
authors.initials: K
authors.lastname: Kinjo
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Iseki
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ohya
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D055109:Ankle Brachial Index; D044466:Asian People; D001794:Blood Pressure; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology*; D011507:Proteinuria / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology*; D063177:Pulse Wave Analysis; D059289:Vascular Stiffness / Q000502:physiology; D055815:Young Adult