title: Investigation of Spatial Clustering of Biliary Tract Cancer Incidence in Osaka, Japan: Neighborhood Effect of a Printing Factory.
abstract: BACKGROUND
  In 2013, an unusually high incidence of biliary tract cancer among current or former workers of the offset color proof printing department of a printing company in Osaka, Japan, was reported. The purpose of this study was to examine whether distance from the printing factory was associated with incidence of biliary tract cancer and whether incident biliary tract cancer cases clustered around the printing factory in Osaka using population-based cancer registry data.
  
  
  METHODS
  We estimated the age-standardized incidence ratio of biliary tract cancer according to distance from this printing factory. We also searched for clusters of biliary tract cancer incidence using spatial scan statistics.
  
  
  RESULTS
  We did not observe statistically significantly high or low standardized incidence ratios for residents in each area categorized by distance from the printing factory for the entire sample or for either sex. The scan statistics did not show any statistically significant clustering of biliary tract cancer incidence anywhere in Osaka prefecture in 2004-2007.
  
  
  CONCLUSIONS
  There was no statistically significant clustering of biliary tract cancer incidence around the printing factory or in any other areas in Osaka, Japan, between 2004 and 2007. To date, even if some substances have diffused outside this source factory, they do not appear to have influenced the incidence of biliary tract cancer in neighboring residents.
authors.affiliation: Center for Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Ito
authors.forename: Tomoki
authors.initials: T
authors.lastname: Nakaya
authors.forename: Akiko
authors.initials: A
authors.lastname: Ioka
authors.forename: Tomio
authors.initials: T
authors.lastname: Nakayama
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tsukuma
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Uehara
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kogawa Sato
authors.forename: Ginji
authors.initials: G
authors.lastname: Endo
authors.forename: Tomoshige
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D001661:Biliary Tract Neoplasms / Q000453:epidemiology*; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D015994:Incidence; D007221:Industry; D007564:Japan / Q000453:epidemiology; D008297:Male; D011327:Printing; D012042:Registries; D012111:Residence Characteristics / Q000706:statistics & numerical data*; D062206:Spatial Analysis