title: Arsenic methylation capability and hypertension risk in subjects living in arseniasis-hyperendemic areas in southwestern Taiwan.
abstract: BACKGROUND
  Cumulative arsenic exposure (CAE) from drinking water has been shown to be associated with hypertension in a dose-response pattern. This study further explored the association between arsenic methylation capability and hypertension risk among residents of arseniasis-hyperendemic areas in Taiwan considering the effect of CAE and other potential confounders.
  
  
  METHODS
  There were 871 subjects (488 women and 383 men) and among them 372 were diagnosed as having hypertension based on a positive history or measured systolic blood pressure >or=140 mm Hg and/or diastolic blood pressure >or=90 mm Hg. Urinary arsenic species were determined by high-performance liquid chromatography-hydride generator and atomic absorption spectrometry. Primary arsenic methylation index [PMI, defined as monomethylarsonic acid (MMA(V)) divided by (As(III)+As(V))] and secondary arsenic methylation index (SMI, defined as dimethylarsinic acid divided by MMA(V)) were used as indicators for arsenic methylation capability.
  
  
  RESULTS
  The level of urinary arsenic was still significantly correlated with cumulative arsenic exposure (CAE) calculated from a questionnaire interview (p=0.02) even after the residents stopped drinking the artesian well water for 2-3 decades. Hypertensive subjects had higher percentages of MMA(V) and lower SMI than subjects without hypertension. However, subjects having CAE >0 mg/L-year had higher hypertension risk than those who had CAE=0 mg/L-year disregard a high or low methylation index.
  
  
  CONCLUSIONS
  Inefficient arsenic methylation ability may be related with hypertension risk.
authors.affiliation: Graduate Institute of Medical Sciences, School of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Yung-Kai
authors.initials: YK
authors.lastname: Huang
authors.forename: Chin-Hsiao
authors.initials: CH
authors.lastname: Tseng
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Huang
authors.forename: Mo-Hsiung
authors.initials: MH
authors.lastname: Yang
authors.forename: Chien-Jen
authors.initials: CJ
authors.lastname: Chen
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Hsueh
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology; D001151:Arsenic / Q000097:blood / Q000378:metabolism* / Q000652:urine; D020261:Arsenic Poisoning / Q000453:epidemiology* / Q000235:genetics / Q000378:metabolism*; D001152:Arsenicals / Q000097:blood / Q000378:metabolism / Q000652:urine; D001794:Blood Pressure / Q000502:physiology; D002784:Cholesterol / Q000097:blood; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D006973:Hypertension / Q000139:chemically induced / Q000453:epidemiology* / Q000378:metabolism*; D008055:Lipids / Q000097:blood; D008297:Male; D008745:Methylation; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D013054:Spectrophotometry, Atomic; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology; D014280:Triglycerides / Q000097:blood
chemical_list: D001152:Arsenicals; D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol; C020300:monomethylarsonic acid; D001151:Arsenic