Abstract and Introduction
Cancer incidence varies among American Indian and Alaska Native (AI/AN) populations, as well as between AI/AN and White populations. This study examined trends for cancers with elevated incidence among AI/AN compared with non-Hispanic White populations and estimated potentially avoidable incident cases among AI/AN populations. Incident cases diagnosed during 2012–2016 were identified from population-based cancer registries and linked with the Indian Health Service patient registration databases to improve racial classification of AI/AN populations. Age-adjusted rates (per 100,000) and trends were calculated for cancers with elevated incidence among AI/AN compared with non-Hispanic White populations (rate ratio of >1.0) according to region. Trends were estimated using joinpoint regression analyses. Expected cancers were estimated by applying age-specific cancer incidence rates among non-Hispanic White populations to population estimates for AI/AN populations. Excess cancer cases among AI/AN populations were defined as observed minus expected cases. Liver, stomach, kidney, lung, colorectal, and female breast cancers had higher incidence rates among AI/AN populations across most regions. Between 2012 and 2016, nearly 5,200 excess cancers were diagnosed among AI/AN populations, with the largest number of excess cancers (1,925) occurring in the Southern Plains region. Culturally informed efforts could reduce cancer disparities associated with these and other cancers among AI/AN populations.
Previous data have showed that cancer incidence rates among American Indian and Alaska Native (AI/AN) populations varied substantially from those of the general US population. In addition, cancer incidence rates among AI/AN populations varied by geographic region and cancer type. Therefore, cancer incidence data, aggregated at the national level, is likely to mask substantial disparities and variations in cancer incidence rates among AI/AN populations and between AI/AN and non-Hispanic White populations.
The present study provides an overview of the leading cancer types with elevated incidence rates among AI/AN populations compared with the non-Hispanic White population during 2012–2016. We identified cancers with elevated incidence among AI/AN populations overall and according to region and assessed the long-term trends of these cancers during 1999–2016. Prior studies have shown disparities in cancer incidence rates for common cancer types among AI/AN and non-Hispanic White populations; however, these studies did not specifically evaluate the cancers that disproportionately affect AI/AN populations. The purpose of this study was to highlight which cancers contribute to the largest relative disparities among AI/AN populations and to quantify the impact of these disparities (i.e., excess cases) between AI/AN and non-Hispanic White populations according to geographic region. These data provide information that could be used to target public health interventions to reduce health inequities among AI/AN populations.
Am J Epidemiol. 2021;190(4):528-538. © 2021 Oxford University Press