title: Association between urinary 6-sulfatoxymelatonin excretion and arterial stiffness in the general elderly population: the HEIJO-KYO cohort.
abstract: BACKGROUND
  Melatonin may have a preventive effect on atherosclerosis by regulating sleep quality and circadian biological rhythmicity. However, whether endogenous melatonin is associated with arterial stiffness, a marker reflecting atherosclerosis, is unclear.
  
  
  OBJECTIVE
  The objective of the study was to determine the association between endogenous melatonin and arterial stiffness.
  
  
  METHODS
  A total of 641 community-based elderly individuals were enrolled in this cross-sectional study (mean age 71.4 y).
  
  
  METHODS
  We measured overnight urinary 6-sulfatoxymelatonin excretion (UME) and cardioankle vascular index (CAVI) as indices of melatonin secretion and arterial stiffness, respectively.
  
  
  RESULTS
  The median UME was 6.8 μg (interquartile range 4.1-10.5) and the mean value of CAVI was 9.1 ± 1.1. High CAVI (ie, ≥ 9.0) was observed in 334 participants (52.1%). Univariate logistic regression models revealed marginal to significant associations between high CAVI and age, gender, body mass index, hypertension, diabetes, estimated glomerular filtration rate, log-transformed UME, bedtime, duration in bed, daytime physical activity, and log-transformed nighttime physical activity. In the multivariate logistic regression model, simultaneously adjusted for the former independent variables, higher log-transformed UME was significantly associated with a lower odds ratio (OR) for high CAVI (adjusted OR 0.708; 95% confidence interval 0.536-0.935; P = .015). This inverse association between log-transformed UME and high CAVI indicated that an increase in log-transformed UME by 1 SD was associated with an 18.1% (95% confidence interval 1.4-31.9) decrease in high CAVI prevalence.
  
  
  CONCLUSIONS
  UME is significantly and inversely associated with arterial stiffness in the general elderly population. The association was independent of several major causes of atherosclerosis.
authors.affiliation: Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara 634-8521, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Obayashi
authors.forename: Keigo
authors.initials: K
authors.lastname: Saeki
authors.forename: Norio
authors.initials: N
authors.lastname: Kurumatani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D055109:Ankle Brachial Index; D050197:Atherosclerosis / Q000453:epidemiology* / Q000378:metabolism*; D015415:Biomarkers / Q000652:urine; D015992:Body Mass Index; D002940:Circadian Rhythm / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D012307:Risk Factors; D059289:Vascular Stiffness / Q000502:physiology*
chemical_list: D015415:Biomarkers; C054513:6-sulfatoxymelatonin; D008550:Melatonin