Indian Health Service Regions Research Articles

Trends in Alzheimer Disease Mortality Among American Indian and Alaska Native People Between 2011 and 2019.

The number of American Indian and Alaska Native (AI/AN) people living with dementia is expected to increase 5-fold by 2060. Social determinants of health may explain disparities in the incidence of Alzheimer disease (AD) but remain largely overlooked. We examined the time trend of AD mortality rates and associations of the percentage of AI/ANs, density of primary care physicians and neurologists, area deprivation index, rurality, and Indian Health Service region with AD mortality in 646 purchased/referred care delivery area counties. AD mortality rates significantly increased over time. Counties with higher concentrations of AI/AN people had lower AD mortality. More deprived counties had 34% higher AD mortality compared with less deprived counties. AD mortality was 20% lower in nonmetro counties than in metro counties. Findings have implications for prioritizing areas where more resources for AD care, education, or outreach are needed.

Choice of Survival Metric and Its Impacts on Cancer Survival Estimates for American Indian and Alaska Native People.

Different survival metrics have different applicability to clinical practice and research. We evaluated how choice of survival metric influences assessment of cancer survival among American Indian and Alaska Native (AIAN) people relative to non-Hispanic Whites (NHW). A secondary objective was to present variations in survival among AIAN people by age, sex, stage, and Indian Health Service (IHS) region. Five-year survival was calculated using the North American Association of Central Cancer Registries Cancer in North America dataset. We calculated survival among AIAN people, compared with NHW using four approaches: (i) observed (crude) survival, (ii) cause-specific survival, (iii) relative survival using age- and sex-adjusted lifetables, and (iv) relative survival using lifetables additionally adjusted for race, geography, and socioeconomic status. For AIAN people, we evaluated how survival varied by age, stage at diagnosis, and IHS region. Observed survival methods produced the lowest estimates, and-excepting prostate cancer-cause-specific methods produced the highest survival estimates. Survival was lower among AIAN people than NHW for all methods. Among AIAN people, survival was higher among those 20-64 years, females, and tumors diagnosed at local stage. Survival varied by IHS region and cancer sites. These results support the assertion that using the same methodology to compare survival estimates between racial and ethnic groups is of paramount importance, but that the choice of metric requires careful consideration of study objectives. These findings have the potential to impact choice of survival metric to explore disparities among AIAN people.

Health-Related Behavioral Risk Factors and Obesity Among American Indians and Alaska Natives of the United States: Assessing Variations by Indian Health Service Region.

IntroductionHealth-related behavioral risk factors and obesity are linked to high risk for multiple chronic diseases. We examined the prevalence of these risk factors among American Indians and Alaska Natives (AI/ANs) compared with that of non-Hispanic Whites and across Indian Health Service (IHS) regions.MethodsWe used 2017 Behavioral Risk Factor Surveillance System data from participants in 50 states and the District of Columbia to assess 4 behavioral risk factors (current cigarette smoking, heavy drinking, binge drinking, and physical inactivity) and obesity. We analyzed disparities in these risk factors between AI/AN and non-Hispanic White participants, nationwide and by IHS region, by conducting log-linear regression analyses while controlling for potential confounders.ResultsNationwide, crude prevalence of current smoking, physical inactivity, and obesity were significantly higher among AI/AN than non-Hispanic White participants. After adjustment for sociodemographic characteristics, AI/AN participants were 11% more likely to report current smoking (P < .05) and 23% more likely to report obesity (P < .001) than non-Hispanic White participants. These patterns persisted in most IHS regions with some exceptions. In the Southwest region, AI/AN participants were 39% less likely to report current smoking than non-Hispanic White participants (P < .001). In the Pacific Coast region, compared with non-Hispanic White participants, AI/AN participants were 54% less likely to report heavy drinking (P < .01) but 34% more likely to report physical inactivity (P < .05). Across IHS regions, AI/AN participants residing in Alaska and the Northern Plains regions had the highest prevalence of current smoking and binge drinking, and those in the Southwest and Pacific Coast regions had the lowest prevalence of current smoking. AI/AN participants in the Southwest region had the lowest prevalence of physical inactivity, and those in the Southern Plains region had the highest prevalence of obesity.ConclusionsThe findings of this study support the importance of public health efforts to address and improve behavioral risk factors related to chronic disease in AI/AN people, both nationwide and among IHS regions, through culturally appropriate interventions.

Traumatic Brain Injury-Related Emergency Department Visits Among American Indian and Alaska Native Persons-National Patient Information Reporting System, 2005-2014.

The American Indian/Alaska Native (AI/AN) population has a disproportionately high rate of traumatic brain injuries (TBIs). However, there is little known about incidence and common mechanisms of injury among AI/AN persons who seek care in an Indian Health Service (IHS) or tribally managed facility. Using the IHS National Patient Information Reporting System, we assessed the incidence of TBI-related emergency department visits among AI/AN children and adults seen in IHS or tribally managed facilities over a 10-year period (2005-2014). There were 44 918 TBI-related emergency department visits during the study period. Males and persons aged 18 to 34 years and 75 years and older had the highest rates of TBI-related emergency department visits. Unintentional falls and assaults contributed to the highest number and proportion of TBI-related emergency department visits. The number and age-adjusted rate of emergency department visits for TBI were highest among persons living in the Southwest and Northern Plains when compared with other IHS regions. Thousands of AI/AN children and adults are seen each year in emergency departments for TBI and the numbers increased over the 10-year period examined. Evidence-based interventions to prevent TBI-related emergency department visits, such as programs to reduce the risk for older adult falls and assault, are warranted.

Trends in Cancer Incidence Among American Indians and Alaska Natives and Non-Hispanic Whites in the United States, 1999-2015.

Female breast, prostate, lung, and colorectal cancers are the leading incident cancers among American Indian and Alaska Native (AI/AN) and non-Hispanic White (NHW) persons in the United States. To understand racial differences, we assessed incidence rates, analyzed trends, and examined geographic variation in incidence by Indian Health Service regions. To assess differences in incidence, we used age-adjusted incidence rates to calculate rate ratios (RRs) and 95% confidence intervals (CIs). Using joinpoint regression, we analyzed incidence trends over time for the four leading cancers from 1999 to 2015. For all four cancers, overall and age-specific incidence rates were lower among AI/ANs than NHWs. By Indian Health Service regions, incidence rates for lung cancer were higher among AI/ANs than NHWs in Alaska (RR: 1.46; 95% CI: 1.37, 1.56) and Northern (RR: 1.29; 95% CI: 1.25, 1.33) and Southern (RR: 1.06; 95% CI: 1.03, 1.09) Plains. Similarly, colorectal cancer incidence rates were higher in AI/ANs than NHWs in Alaska (RR: 2.29; 95% CI: 2.14, 2.45) and Northern (RR: 1.04; 95% CI: 1.00, 1.09) and Southern (RR: 1.11; 95% CI: 1.07, 1.15) Plains. Also, AI/AN women in Alaska had a higher incidence rate for breast cancer than NHW women (RR: 1.05; 95% CI: 1.05, 1.20). From 1999 to 2015, incidence rates for all four cancers decreased in NHWs, but only rates for prostate (average annual percent change: -4.70) and colorectal (average annual percent change: -1.80) cancers decreased considerably in AI/ANs. Findings from this study highlight the racial and regional differences in cancer incidence.

Human Papillomavirus Vaccine Uptake: Increase for American Indian Adolescents, 2013–2015

Although Indian Health Service, tribally-operated, and urban Indian (I/T/U) healthcare facilities have higher human papillomavirus (HPV) vaccine series initiation and completion rates among adolescent patients aged 13-17 years than the general U.S. population, challenges remain. I/T/U facilities have lower coverage for HPV vaccine first dose compared with coverage for other adolescent vaccines, and HPV vaccine series completion rates are lower than initiation rates. Researchers aimed to assist I/T/U facilities in identifying interventions to increase HPV vaccination series initiation and completion rates. Best practice and intervention I/T/U healthcare facilities were identified based on baseline adolescent HPV vaccine coverage data. Healthcare professionals were interviewed about barriers and facilitators to HPV vaccination. Researchers used responses and evidence-based practices to identify and assist facilities in implementing interventions to increase adolescent HPV vaccine series initiation and completion. Coverage and interview data were collected from June 2013 to June 2015; data were analyzed in 2015. I/T/U healthcare facilities located within five Indian Health Service regions. Interventions included analyzing and providing feedback on facility vaccine coverage data, educating providers about HPV vaccine, expanding access to HPV vaccine, and establishing or expanding reminder recall and education efforts. Impact of evidence-based strategies and best practices to support HPV vaccination. Mean baseline first dose coverage with HPV vaccine at best practice facilities was 78% compared with 46% at intervention facilities. Mean third dose coverage was 48% at best practice facilities versus 19% at intervention facilities. Intervention facilities implemented multiple low-cost, evidence-based strategies and best practices to increase vaccine coverage. At baseline, most facilities used electronic provider reminders, had standing orders in place for administering HPV vaccine, and administered tetanus, diphtheria, and acellular pertussis and HPV vaccines during the same visit. At intervention sites, mean coverage for HPV initiation and completion increased by 24% and 22%, respectively. A tailored multifaceted approach addressing vaccine delivery processes and patient and provider education may increase HPV vaccine coverage.

Time-to-Treatment for Myocardial Infarction: Barriers and Facilitators Perceived by American Indians in Three Regions

Early recognition of acute myocardial infarction (MI), followed by prompt emergency care, improves patient outcomes. Among rural American Indian (AI) populations there are disparities in access to care for MI and processes of care, resulting in poor MI-related health outcomes compared to the general population. We sought to gain an understanding of barriers related to MI time-to-treatment delays using a qualitative approach. We conducted semi-structured interviews and focus groups with AI key informants and community members in three Indian Health Service regions. Major barriers to care included long travel distance to care and lack of supporting infrastructure; distrust of the health care system; low overall literacy and basic health literacy; priority of family care-giving; and lack of specialized medical facilities and specialists. Findings suggest that improved time-to-treatment facilitators include educating the local community about the causes and consequences of MI and culturally-sensitive health communication, as well as addressing the quality of local systems of care and the community's perception of these systems. Pursuing these strategies may improve quality of care and reduce MI-related morbidity and mortality in rural AI populations.

Homicide Among American Indians/Alaska Natives, 1999-2009: Implications for Public Health Interventions.

We determined estimates of homicide among American Indians/Alaska Natives (AI/ANs) compared with non-Hispanic white people to characterize disparities and improve AI/AN classification in incidence and mortality reporting. We linked 1999-2009 death certificate data with Indian Health Service (IHS) patient registration data to examine death rates from homicide among AI/AN and non-Hispanic white people. Our analysis focused primarily on residents of IHS Contract Health Service Delivery Area counties and excluded Hispanic people to avoid underestimation of incidence and mortality in AI/ANs and for consistency in our comparisons. We used age-adjusted death rates per 100,000 population and stratified our analyses by sex, age, and IHS region. Death rates per 100,000 population from homicide were four times higher among AI/ANs (rate = 12.1) than among white people (rate = 2.8). Homicide rates for AI/ANs were highest in the Southwest (25.6 and 6.9 for males and females, respectively) and in Alaska (17.7 and 10.3 for males and females, respectively). Disparities between AI/ANs and non-Hispanic white people were highest in the Northern Plains region among men (rate ratio [RR] = 9.8, 95% confidence interval [CI] 8.5, 11.3) and among those aged 25-44 years (RR59.0, 95% CI 7.5, 10.7) and 0-24 years (RR57.4, 95% CI 6.1, 8.9). Death rates from homicide among AI/ANs were higher than previously reported and varied by sex, age, and region. Violence prevention efforts involving a range of stakeholders are needed at the community level to address this important public health issue.

Lung Cancer Deaths Among American Indians and Alaska Natives, 1990–2009

We examined regional differences in lung cancer among American Indians/Alaska Natives (AI/ANs) using linked data sets to minimize racial misclassification. On the basis of federal lung cancer incidence data for 1999 to 2009 and deaths for 1990 to 2009 linked with Indian Health Service (IHS) registration records, we calculated age-adjusted incidence and death rates for non-Hispanic AI/AN and White persons by IHS region, focusing on Contract Health Service Delivery Area (CHSDA) counties. We correlated death rates with cigarette smoking prevalence and calculated mortality-to-incidence ratios. Lung cancer death rates among AI/AN persons in CHSDA counties varied across IHS regions, from 94.0 per 100,000 in the Northern Plains to 15.2 in the Southwest, reflecting the strong correlation between smoking and lung cancer. For every 100 lung cancers diagnosed, there were 6 more deaths among AI/AN persons than among White persons. Lung cancer death rates began to decline in 1997 among AI/AN men and are still increasing among AI/AN women. Comparison of regional lung cancer death rates between AI/AN and White populations indicates disparities in tobacco control and prevention interventions. Efforts should be made to ensure that AI/AN persons receive equal benefit from current and emerging lung cancer prevention and control interventions.

Suicide mortality among American Indians and Alaska Natives, 1999-2009.

We assessed national and regional suicide mortality for American Indian and Alaska Native (AI/AN) persons. We used 1999 to 2009 death certificate data linked with Indian Health Service (IHS) patient registration data to examine death rates from suicide in AI/AN and White persons. Analysis focused primarily on residents of IHS Contract Health Service Delivery Area counties; Hispanics were excluded. We used age-adjusted death rates per 100,000 population and stratified our analyses by age and IHS region. Death rates from suicide were approximately 50% higher among AI/AN persons (21.2) than Whites (14.2). By region, rates for AI/AN people were highest in Alaska (rates = 65.4 and 19.3, for males and females, respectively) and in the Northern Plains (rates = 41.6 and 11.9 for males and females, respectively). Disparities between AI/AN and White rates were also highest in these regions. A coordinated, multidisciplinary effort involving federal, state, local, and tribal health officials is needed to address this important public health issue.

Diabetes-Related Mortality Among American Indians and Alaska Natives, 1990–2009

We assessed diabetes-related mortality for American Indians and Alaska Natives (AI/ANs) and Whites. Study populations were non-Hispanic AI/AN and White persons in Indian Health Service (IHS) Contract Health Service Delivery Area counties; Hispanics were excluded. We used 1990 to 2009 death certificate data linked to IHS patient registration records to identify AI/AN decedents aged 20 years or older. We examined disparities and trends in mortality related to diabetes as an underlying cause of death (COD) and as a multiple COD. After increasing between 1990 and 1999, rates of diabetes as an underlying COD and a multiple COD subsequently decreased in both groups. However, between 2000 and 2009, age-adjusted rates of diabetes as an underlying COD and a multiple COD remained 2.5 to 3.5 times higher among AI/AN persons than among Whites for all age groups (20-44, 45-54, 55-64, 65-74, and ≥ 75 years), both sexes, and every IHS region except Alaska. Declining trends in diabetes-related mortality in both AI/AN and White populations are consistent with recent improvements in their health status. Reducing persistent disparities in diabetes mortality will require developing effective approaches to not only control but also prevent diabetes among AI/AN populations.

Racial misclassification of American Indians and Alaska Natives by Indian Health Service Contract Health Service Delivery Area.

We evaluated the racial misclassification of American Indians and Alaska Natives (AI/ANs) in cancer incidence and all-cause mortality data by Indian Health Service (IHS) Contract Health Service Delivery Area (CHSDA). We evaluated data from 3 sources: IHS-National Vital Statistics System (NVSS), IHS-National Program of Cancer Registries (NPCR)/Surveillance, Epidemiology and End Results (SEER) program, and National Longitudinal Mortality Study (NLMS). We calculated, within each data source, the sensitivity and classification ratios by sex, IHS region, and urban-rural classification by CHSDA county. Sensitivity was significantly greater in CHSDA counties (IHS-NVSS: 83.6%; IHS-NPCR/SEER: 77.6%; NLMS: 68.8%) than non-CHSDA counties (IHS-NVSS: 54.8%; IHS-NPCR/SEER: 39.0%; NLMS: 28.3%). Classification ratios indicated less misclassification in CHSDA counties (IHS-NVSS: 1.20%; IHS-NPCR/SEER: 1.29%; NLMS: 1.18%) than non-CHSDA counties (IHS-NVSS: 1.82%; IHS-NPCR/SEER: 2.56%; NLMS: 1.81%). Race misclassification was less in rural counties and in regions with the greatest concentrations of AI/AN persons (Alaska, Southwest, and Northern Plains). Limiting presentation and analysis to CHSDA counties helped mitigate the effects of race misclassification of AI/AN persons, although a portion of the population was excluded.

Lymphocytic Choriomeningitis Virus Infections among American Indians

Lymphocytic Choriomeningitis Virus Infections among American Indians

Prevalence Estimates of Parkinson Disease among American Indian and Alaska Native People (P07.130)

Objective: To determine the prevalence of Parkinson disease (PD) among American Indian and Alaska Native (AI/AN) people. Background Health disparity, related to underfunding and rural living environments, continues to be a major problem for AI/AN people. Neurological diseases, like PD, may be under-recognized and under-treated, which negatively impacts quality of life and health for those living on reservations. Design/Methods: We analyzed records for AI/AN people with PD during 2002-2009 using inpatient and outpatient direct and contract health care data from the Indian Health Service (IHS). The PD case definition included at least one inpatient or two outpatient visits with a PD diagnosis. For prevalence rate calculations, the population was the number of AI/AN patients seen within the IHS health care system for any reason during the study period. Crude and age-adjusted prevalence, using the 2000 projected US population as the standard, were determined overall and by age group, gender, time period and IHS region. Results: Among almost 2 million AI/AN people, 2613 carried the diagnosis of PD (crude prevalence = 143.8/100,000). The prevalence increased with age through 84 years of age. The overall age-adjusted rate for AI/AN people was 355.7; 822.6 for those aged >40 years and 2350.4 for >65 years. Age-adjusted prevalence was higher among men than women (p Conclusions: Parkinson disease is at least as prevalent among AI/AN people as other populations. Similar to other reports, the prevalence of PD increased with age, was higher in men than women and varied by geographic region. Community-based studies are needed to define incidence, examine risk factors, and determine reasons for gender and regional differences in PD among AI/AN people. Disclosure: Dr. Gordon has nothing to disclose. Dr. Mehal has nothing to disclose. Dr. Holman has nothing to disclose. Dr. Rowland has nothing to disclose. Dr. Cheek has nothing to disclose.

Impact of Rotavirus Vaccine on Diarrhea-Associated Disease Burden Among American Indian and Alaska Native Children

Beginning in 2006, the Indian Health Service (IHS) began rotavirus vaccination of American Indian and Alaska Native (AI/AN) infants. To assess vaccine impact, we examined trends in IHS diarrhea-associated hospitalization and outpatient visits among AI/AN children in the pre- and postrotavirus vaccine era. Diarrhea-associated hospitalizations and outpatient visits among AI/AN children <5 years of age during 2001 through 2010 were examined by gender, age group, and region for prevaccine years 2001-2006 and postvaccine years 2008, 2009, and 2010. To account for secular declining trends observed in prevaccine years, expected diarrhea-associated hospitalization and outpatient rates for postvaccine years were generated by using Poisson regression analysis of the 2001-2006 annual rates. Coverage with at least 1 dose of rotavirus vaccine among AI/AN infants aged 3 to 5 months in the first half of 2008, 2009, and 2010 ranged from 48% to 80% in various IHS regions. The prevaccine average annual diarrhea-associated hospitalization rates among AI/AN children <5 years of age was 63 per 10 000 persons (range: 57-75 per 10 000), and declined to 39, 31, and 27 per 10 000 in 2008, 2009, and 2010, respectively. Observed 2008, 2009, and 2010 rates were 24%, 37%, and 44% lower than expected rates, respectively. Decreases in diarrhea-associated hospitalizations and outpatient visits were observed in all IHS regions. Diarrhea-associated hospitalization and outpatient visit rates among AI/AN children have declined after implementation of rotavirus vaccination in AI/AN populations.

Cancer in American Indian and Alaska Native young adults (ages 20-44 years): US, 1999-2004

An examination of cancer incidence patterns in American Indians and Alaska Native (AI/AN) young adults may provide insight into their present and future cancer burden. To reduce racial misclassification, incidence data were linked with the Indian Health Service (IHS) patient services database. Age-adjusted cancer incidence rates per 100,000 (AAR) and corresponding rate ratios (RR) for young adults (ages 20-44 years) were compared across IHS regions and for selected cancers within Contract Health Service Delivery Area counties by race (AI/AN vs non-Hispanic whites [NHW]) and sex. The all-sites cancer incidence rate was lower for AI/ANs (AAR of 83.8) than for NHWs (AAR of 111.2) (RR of 0.75) but varied by IHS regions. Among the leading cancers in AI/AN females the risk was elevated for stomach (RR of 3.22), colorectal (RR of 1.30), uterine (RR of 1.61), and kidney (RR of 1.39) cancers and was lower for breast (RR of 0.70) and thyroid (RR of 0.71) cancers. Among AI/AN young adult males the risk was elevated for stomach (RR of 2.62), liver (RR of 1.89), and kidney (RR of 1.59) cancers and lower for testicular germ cell cancer (RR of 0.64) and lymphoma (RR of 0.60). The risk for these and other cancers varied across IHS regions. Many of the cancer patterns that characterize the AI/AN population overall are apparent among young adults. Compared with NHW young adults, the overall cancer burden among AI/AN young adults was lower but varied for selected cancers and across IHS regions. Cancer control and research strategies are needed to address the unique genetic, social, cultural, and lifestyle aspects of AI/AN young adults.

Gallbladder cancer incidence among American Indians and Alaska Natives, US, 1999-2004

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. 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. 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. 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.

Lung cancer incidence among American Indians and Alaska Natives in the United States, 1999-2004.

Lung cancer incidence rates among American Indians and Alaska Natives (AI/ANs) in the United States have not been described well, primarily because of race misclassification and, until the 1990s, incomplete coverage of their population by cancer registries. Smoking, the predominant cause of lung cancer, is particularly prevalent among this population. Data from the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results Program were combined to estimate age-adjusted incidence rates of lung cancer during 1999 through 2004. Cases were linked to Indian Health Service (IHS) registration databases to identify AI/ANs whose race may have been misclassified. Age-adjusted rates were calculated for Contract Health Service Delivery Area (CHSDA) counties and for all counties by IHS region, and comparisons were made between AI/ANs and non-Hispanic whites (NHWs). Among populations living in CHSDA counties, NHWs overall had higher rates of lung cancer than AI/ANs. However, the rates (per 100,000 population) among AI/ANs varied substantially between IHS regions from 14.9 (Southwest) to 87.1 (Southern Plains), 93.2 (Alaska), and 104.3 (Northern Plains). Approximately 41.6% of AI/AN lung cancer cases were diagnosed before age 65 years compared with approximately 29.8% of NHW lung cancer cases. The overall percentage stage distribution was not different between AI/ANs and NHWs. Squamous cell carcinomas were slightly more common and adenocarcinomas were less common among AI/ANs than among NHWs. Lung cancer rates were not decreasing for AI/ANs as they were for NHWs. Data from this study clarified the need for culturally appropriate tobacco prevention and control policies and resources for AI/ANs in all regions, and especially in the Plains and Alaska.

Regional differences in cervical cancer incidence among American Indians and Alaska Natives, 1999-2004

Reports from limited geographic regions indicate higher rates of cervical cancer incidence in American Indian and Alaska Native (AI/AN) women than in women of other races. However, accurate determinations of cervical cancer incidence in AI/AN women have been hampered by racial misclassification in central cancer registries. The authors linked data from cancer registries participating in the National Program of Cancer Registries (NPCR) and the Surveillance, Epidemiology, and End Results (SEER) Program with Indian Health Service (IHS) enrollment records to improve identification of AI/AN race. NPCR and SEER data were combined to estimate annualized age-adjusted rates (expressed per 100,000 persons) for the diagnosis years 1999 to 2004. Analyses focused on counties known to have less racial misclassification, and results were stratified by IHS Region. Approximately 56% of AI/ANs in the US reside in these counties. The authors examined overall and age-specific incidence rates and stage at diagnosis for AI/AN women compared with non-Hispanic white (NHW) women. Invasive cervical cancer incidence rates among AI/AN women varied nearly 2-fold across IHS regions, with the highest rates reported in the Southern Plains (14.1) and Northern Plains (12.5); the lowest rates were in the Eastern region and the Pacific Coast. Overall, AI/AN women had higher rates of cervical cancer than NHW women and were more likely to be diagnosed with later stage disease. The wide regional variation of invasive cervical cancer incidence indicates an important need for health services research regarding cervical cancer screening and prevention education as well as policy development regarding human papillomavirus vaccine use, particularly in the regions with high incidence rates. Cancer 2008;113(5 suppl):1234-43. Published 2008 by the American Cancer Society.

Cancer among American Indians and Alaska Natives in the United States, 1999-2004

Cancer incidence rates vary among American Indian and Alaska Native (AI/AN) populations and often differ from rates among non-Hispanic whites (NHWs). However, the misclassification of race for AI/AN cancer cases in central cancer registries may have led to underestimates of the AI/AN cancer burden in previous reports. Cases diagnosed during 1999 through 2004 were identified from population-based cancer registries in the United States. Age-adjusted rates were calculated for the 25 most common sites for AI/ANs and NHWs. To minimize the misclassification of race, cancer registry records were linked with patient registration files from the Indian Health Service (IHS). Analyses were restricted to Contract Health Service Delivery Area (CHSDA) counties and were stratified by IHS region. In CHSDA counties, cancer incidence rates among AI/ANs varied widely by region, whereas rates among NHWs did not. For all cancer sites combined, AI/AN rates were higher than NHW rates among both males and females in the Northern and Southern Plains, and among Alaska Native Females; AI/AN rates were lower than NHW rates in the Southwest, the Pacific Coast, and the East. Lung cancer and colorectal cancer rates for AI/ANs exceeded rates for NHWs in Alaska and the Northern Plains. Rates for stomach, gallbladder, kidney, and liver cancer were higher among AI/ANs than among NHWs overall, in Alaska, in the Plains regions, and in the Southwest. Regional differences in cancer incidence rates among AI/AN populations were not obvious from nationwide data and highlighted opportunities for cancer control and prevention. It is unlikely that such differences are explained by race misclassification.