title: Negative association between serum parathyroid hormone levels and urinary perchlorate, nitrate, and thiocyanate concentrations in U.S. adults: the National Health and Nutrition Examination Survey 2005-2006.
abstract: OBJECTIVE
  Perchlorate, nitrate, and thiocyanate are well-known inhibitors of the sodium-iodide symporter and may disrupt thyroid function. This exploratory study investigated the association among urinary perchlorate, nitrate, and thiocyanate concentrations and parathyroid hormone (PTH) levels in the general U.S. population.
  
  
  METHODS
  We analyzed data on 4265 adults (aged 20 years and older) from the National Health and Nutrition Examination Survey in 2005 through 2006 to evaluate the relationship among urinary perchlorate, nitrate, and thiocyanate concentration and PTH levels and the presence of hyperparathyroidism cross-sectionally.
  
  
  RESULTS
  The geometric means and 95% confidence interval (95% CI) concentrations of urinary perchlorate, nitrate, and thiocyanate were 3.38 (3.15-3.62), 40363 (37512-43431), and 1129 (1029-1239) ng/mL, respectively. After adjusting for confounding variables and sample weights, creatinine-corrected urinary perchlorate was negatively associated with serum PTH levels in women (P = 0.001), and creatinine-corrected urinary nitrate and thiocyanate were negatively associated with serum PTH levels in both sex groups (P = 0.001 and P<0.001 for men, P = 0.018 and P<0.001 for women, respectively). Similar results were obtained from sensitivity analyses performed for exposure variables unadjusted for creatinine with urinary creatinine added as a separate covariate. There was a negative relationship between hyperparathyroidism and urinary nitrate and thiocyanate [odds ratio (95% CI) = 0.77 (0.60-0.98) and 0.69 (0.61-0.79), respectively].
  
  
  CONCLUSIONS
  A higher urinary concentration of perchlorate, nitrate, and thiocyanate is associated with lower serum PTH levels. Future studies are needed to determine the pathophysiological background of the observation.
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan.
authors.forename: Wen-Ching
authors.initials: WC
authors.lastname: Ko
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan.
authors.forename: Chien-Liang
authors.initials: CL
authors.lastname: Liu
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Department of Pharmacology and Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan.
authors.forename: Jie-Jen
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan.
authors.forename: Tsang-Pai
authors.initials: TP
authors.lastname: Liu
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Department of Pharmacology and Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan.
authors.forename: Po-Sheng
authors.initials: PS
authors.lastname: Yang
authors.affiliation: Institute of Statistical Science, Academia Sinica, Taipei, Taiwan.
authors.forename: Yi-Chiung
authors.initials: YC
authors.lastname: Hsu
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Department of Pharmacology and Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan.
authors.forename: Shih-Ping
authors.initials: SP
authors.lastname: Cheng
mesh_terms: D000328:Adult; D002852:Chromatography, Ion Exchange; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009566:Nitrates / Q000652:urine*; D009749:Nutrition Surveys; D010281:Parathyroid Hormone / Q000097:blood*; D010472:Perchlorates / Q000652:urine*; D027981:Symporters / Q000037:antagonists & inhibitors; D013861:Thiocyanates / Q000652:urine*; D014481:United States; D000099209:Sodium-Iodide Symporters
chemical_list: D009566:Nitrates; D010281:Parathyroid Hormone; D010472:Perchlorates; D027981:Symporters; D013861:Thiocyanates; D000099209:Sodium-Iodide Symporters; C031760:thiocyanate; C494474:perchlorate