title: Urinary melatonin and risk of incident hypertension among young women.
abstract: OBJECTIVE
  Administered in supraphysiologic doses, the hormone melatonin may reduce blood pressure, particularly nocturnal blood pressure. However, whether lower physiologic levels of melatonin are an independent risk factor for the development of hypertension has never been reported.
  
  
  METHODS
  We examined the association between first morning urine melatonin levels and the risk of developing hypertension among 554 young women without baseline hypertension who were followed for 8 years. Cox proportional hazards models were adjusted for age, BMI, physical activity, alcohol intake, smoking status, urinary creatinine, and family history of hypertension.
  
  
  RESULTS
  During 8 years of follow-up, a total of 125 women developed hypertension. The relative risk for incident hypertension among women in the highest quartile of urinary melatonin (>27.0 ng/mg creatinine) as compared with the lowest quartile (<10.1 ng/mg creatinine) was 0.49 (95% confidence interval 0.28-0.85, P < 0.001).
  
  
  CONCLUSIONS
  First morning melatonin levels are independently and inversely associated with incident hypertension; low melatonin production may be a pathophysiologic factor in the development of hypertension.
authors.affiliation: Channing Laboratory, Department of Medicine, 181 Longwood Avenue, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. jforman@partners.org
authors.forename: John P
authors.initials: JP
authors.lastname: Forman
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
authors.forename: Eva S
authors.initials: ES
authors.lastname: Schernhammer
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000652:urine*; D008550:Melatonin / Q000031:analogs & derivatives* / Q000652:urine; D016016:Proportional Hazards Models; D012307:Risk Factors
chemical_list: C054513:6-sulfatoxymelatonin; D008550:Melatonin