title: Geographic patterns of hepatocellular carcinoma mortality with exposure to iron in groundwater in Taiwanese population: an ecological study.
abstract: BACKGROUND
  Many studies have examined the risk factors for HCC (including hepatitis B virus, hepatitis C virus, aflatoxin, retinol, cigarette smoking, and alcohol consumption). However, data from previous studies on the association between iron exposure, land subsidence, and HCC mortality/incidence were limited, especially in Taiwanese population. We aimed to explore the geographical distribution of HCC mortality rates by township-specific data and to evaluate the association between HCC mortality, land subsidence, and iron levels in groundwater in Taiwan.
  
  
  METHODS
  We conducted an ecological study and calculated the HCC age-standardized mortality/incidence rates according to death certificates issued in Taiwan from 1992 to 2001 and incidence data from 1995-1998. The land subsidence dataset before 2005 and iron concentrations in groundwater in 1989 are also involved in this study. Both geographical information systems and Pearson correlation coefficients were used to analyze the relationship between HCC mortality rates, land subsidence, and iron concentrations in groundwater.
  
  
  RESULTS
  Township-specific HCC mortality rates are higher in southwestern coastal townships where serious land subsidence and higher township-specific concentrations of iron in groundwater are present. The Pearson correlation coefficients of iron concentrations in groundwater and ASRs of HCC were 0.286 (P = 0.004) in males and 0.192 (P = 0.058) in females for mortality data; the coefficients were 0.375 (P < 0.001) in males and 0.210 (P = 0.038) in females for incidence data.
  
  
  CONCLUSIONS
  This study showed that HCC mortality is clustered in southwestern Taiwan and the association with the iron levels in groundwater in Taiwanese population warrant further investigation.
authors.affiliation: Jen-Ai Hospital, Taichung City 41265, Taiwan.
authors.forename: Horng-Jeng
authors.initials: HJ
authors.lastname: Shyu
authors.forename: Chia-Chi
authors.initials: CC
authors.lastname: Lung
authors.forename: Chien-Chang
authors.initials: CC
authors.lastname: Ho
authors.forename: Yi-Hua Iris
authors.initials: YH
authors.lastname: Sun
authors.forename: Pei-Chieh
authors.initials: PC
authors.lastname: Ko
authors.forename: Jing-Yang
authors.initials: JY
authors.lastname: Huang
authors.forename: Chia-Chen
authors.initials: CC
authors.lastname: Pan
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Chiang
authors.forename: Shih-Chang
authors.initials: SC
authors.lastname: Chen
authors.forename: Yung-Po
authors.initials: YP
authors.lastname: Liaw
mesh_terms: D000293:Adolescent; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000401:mortality*; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D040362:Geographic Information Systems; D062306:Geography, Medical; D060587:Groundwater / Q000737:chemistry*; D006801:Humans; D007223:Infant; D007501:Iron / Q000506:poisoning*; D008113:Liver Neoplasms / Q000401:mortality*; D008297:Male; D012042:Registries; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology
chemical_list: D007501:Iron