title: Associations of blood and urinary mercury with hypertension in U.S. adults: the NHANES 2003-2006.
abstract: BACKGROUND
  Few studies have examined the association between hypertension and mercury exposure in the general population. We examined cross-sectional associations between blood (mainly methylmercury) or urinary mercury (mainly inorganic mercury) and hypertension in representative U.S. adults and effect modifications by dietary omega-3 fatty acids and serum selenium.
  
  
  METHODS
  We examined 6607 adults aged 20 years or older, using the National Health and Nutrition Examination Survey (NHANES) from 2003/2004 to 2005/2006 (2201 adults were available for urinary mercury from NHANES 2003-2006; 2117 available for serum selenium from NHANES 2003-2004 aged 40 years or older). The average of omega-3 fatty acids from two 24-h recalls was calculated.
  
  
  RESULTS
  The weighted prevalence of hypertension was 32.2%. The geometric means (95% confidence intervals) of blood total and urinary mercury were 1.03 (0.95, 1.11)μg/L and 0.51 (0.47, 0.54)μg/L, respectively. The adjusted odds ratios for a doubling increase in blood mercury and urinary mercury were 0.94 (0.87 to 1.01) and 0.87 (0.78 to 0.99), respectively, after adjusting for potential confounders. The associations remained similar, even after adjusting for either omega-3 fatty acids or selenium or both. No significant effect modification by either omega-3 fatty acids or selenium was observed.
  
  
  CONCLUSIONS
  In this cross-sectional study of the U.S. general population, we found no association of hypertension with blood mercury but a suggestive inverse association with urinary mercury. Future prospective studies are warranted to confirm these findings.
authors.affiliation: Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA. sungkyun@umich.edu
authors.forename: Sung Kyun
authors.initials: SK
authors.lastname: Park
authors.forename: Sunghee
authors.initials: S
authors.lastname: Lee
authors.forename: Niladri
authors.initials: N
authors.lastname: Basu
authors.forename: Alfred
authors.initials: A
authors.lastname: Franzblau
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000652:urine*; D008297:Male; D008628:Mercury / Q000097:blood* / Q000652:urine*; D008875:Middle Aged; D009749:Nutrition Surveys; D012643:Selenium / Q000097:blood
chemical_list: D015525:Fatty Acids, Omega-3; D008628:Mercury; D012643:Selenium