title: Place of birth and risk of gallbladder cancer in India.
abstract: BACKGROUND
  Within India, the incidence of gallbladder cancer (GBC) is characterized by marked geographical variation; however, the reasons for these differences are unclear.
  
  
  OBJECTIVE
  To evaluate the role of place of birth, length of residence, and effect of migration from high- to low-risk region on GBC development.
  
  
  METHODS
  Population-based cancer registries (PBCRs); case-control study.
  
  
  METHODS
  Data of PBCRs were used to demonstrate geographical variation in GBC incidence rates. A case-control study data examined the role of birth place, residence length, and effect of migration in etiology of GBC.
  
  
  METHODS
  Rate ratios for different PBCRs were estimated using Chennai Cancer Registry as the reference population. Odds ratios (ORs) for developing GBC in a high-risk region compared to a low-risk region and associated 95% confidence interval (CI) were estimated through unconditional logistic regression models using case-control study.
  
  
  RESULTS
  GBC shows marked variation in incidence with risk highest in Northeast regions and lowest in South India. OR of 4.82 (95% CI: 3.87-5.99) was observed for developing GBC for individuals born in a high-risk region compared to those born in a low-risk region after adjusting for confounders. A dose-response relationship with increased risk with increased length of residence in a high-risk region was observed (OR lifetime 5.58 [95% CI: 4.42-7.05]; Ptrend ≤ 0.001). The risk persisted even if study participant migrated from high- to low-risk region (OR = 1.36; 95% CI: 1.02-1.82).
  
  
  CONCLUSIONS
  The present study signifies the importance of place of birth, length of stay, and effect of migration from high- to low-risk region in the development of GBC. The data indicate role of environmental and genetic factors in etiology of disease.
authors.affiliation: Centre for Cancer Epidemiology, Tata Memorial Centre, Mumbai, Maharashtra, India.
authors.forename: S S
authors.initials: SS
authors.lastname: Mhatre
authors.affiliation: Centre for Cancer Epidemiology, Tata Memorial Centre, Mumbai, Maharashtra, India.
authors.forename: R T
authors.initials: RT
authors.lastname: Nagrani
authors.affiliation: Centre for Cancer Epidemiology, Tata Memorial Centre, Mumbai, Maharashtra, India.
authors.forename: A
authors.initials: A
authors.lastname: Budukh
authors.affiliation: Chiplunkar Lab, Advanced Center for Treatment, Research and Education in Cancer, Tata Memorial Centre, Navi Mumbai, Maharashtra, India.
authors.forename: S
authors.initials: S
authors.lastname: Chiplunkar
authors.affiliation: Department of Surgical Oncology, Tata Memorial Hospital, Mumbai, Maharashtra, India.
authors.forename: R
authors.initials: R
authors.lastname: Badwe
authors.affiliation: Department of Digestive Diseases and Clinical Nutrition, Tata Memorial Hospital, Mumbai, Maharashtra, India.
authors.forename: P
authors.initials: P
authors.lastname: Patil
authors.affiliation: Section of Cancer Surveillance, International Agency for Research on Cancer, Lyon, France.
authors.forename: M
authors.initials: M
authors.lastname: Laversanne
authors.affiliation: Centre for Global Health, National Cancer Institute, NIH, DHSS, Bethesda, USA.
authors.forename: P
authors.initials: P
authors.lastname: Rajaraman
authors.affiliation: Section of Cancer Surveillance, International Agency for Research on Cancer, Lyon, France.
authors.forename: F
authors.initials: F
authors.lastname: Bray
authors.affiliation: Centre for Cancer Epidemiology, Tata Memorial Centre, Mumbai, Maharashtra, India.
authors.forename: R
authors.initials: R
authors.lastname: Dikshit
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005706:Gallbladder Neoplasms / Q000453:epidemiology*; D020022:Genetic Predisposition to Disease; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D055815:Young Adult