Gallbladder cancer incidence among American Indians and Alaska Natives, US, 1999-2004.
BACKGROUND
Gallbladder cancer (GBC) is rare; however, it disproportionately affects the American Indian and Alaska Natives (AI/AN) population. The purpose of the study was to characterize GBC among AI/AN in the US population.


METHODS
Cases of GBC diagnosed between 1999 and 2004 and collected by state-based cancer registries were included. Registry records were linked with Indian Health Service (IHS) administration records to decrease race misclassification of AI/AN. GBC rates and/or percent distributions for AI/AN and non-Hispanic whites (NHW) were calculated by sex, IHS region, age, and stage for all US counties and IHS Contract Health Service Delivery Area (CHSDA) counties, in which approximately 56% of US AI/AN individuals reside.


RESULTS
In CHSDA counties, the GBC incidence rate among AI/AN was 3.3 per 100,000, which was significantly higher than that among NHW (P < .05). Rates varied widely among IHS regions and ranged from 1.5 in the East to 5.5 in Alaska. Rates were higher among AI/AN females than males in all regions, except the Northern Plains. Higher percentages of GBC were diagnosed among AI/AN aged <65 years compared with NHW. GBC was most often diagnosed at the regional stage among AI/AN, whereas GBC was most often diagnosed at regional or distant stages among NHW.


CONCLUSIONS
To the authors' knowledge to date, this is the most comprehensive study of GBC incidence among AI/AN in the US. The accurate characterization of GBC in this population could help inform the development of interventions aimed at reducing morbidity and mortality from this disease.
Lemrow
Shannon M
SM
Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, Maryland, USA.
Perdue
David G
DG
Stewart
Sherri L
SL
Richardson
Lisa C
LC
Jim
Melissa A
MA
French
Helen T
HT
Swan
Judith
J
Edwards
Brenda K
BK
Wiggins
Charles
C
Dickie
Lois
L
Espey
David K
DK
D000368:Aged; D000413:Alaska / Q000453:epidemiology; D005260:Female; D005706:Gallbladder Neoplasms / Q000208:ethnology*; D005843:Geography; D006801:Humans; D015994:Incidence; D007198:Indians, North American / Q000706:statistics & numerical data*; D004930:Inuit / Q000706:statistics & numerical data*; D008875:Middle Aged; D011159:Population Surveillance; D044469:Racial Groups / Q000706:statistics & numerical data; D012042:Registries; D014481:United States / Q000453:epidemiology