The AI/AN population is culturally diverse and spread among approximately 560 federally recognized tribal communities in 34 states and multiple urban areas (2). Health disparities between the AI/AN population and other racial/ethnic populations are well documented (3). Mortality rates and trends for respiratory diseases indicate that AI/ANs are at increased risk for death resulting from pneumonia and influenza (4,5). Although AI/AN death rates varied among the 12 participating states in this study, the aggregate AI/AN H1N1-related death rate from 12 states was four times higher than that of all other racial/ethnic groups combined.
The higher mortality rate among AI/ANs observed in this investigation is consistent with reports of increased influenza-related morbidity and mortality among indigenous populations in other parts of the world during the current H1N1 pandemic and also is consistent with observations from previous pandemics (1,2). After the influenza pandemic of 1918–19, U.S. government investigators reported that influenza-related mortality rates among AI/ANs were four times higher than the rates observed among persons in general urban populations (2).
The factors that produce a higher influenza mortality rate among AI/ANs are unknown but might include higher prevalence of underlying chronic illness such as diabetes. The age-specific prevalence of diabetes in AI/AN adults is two to three times higher than for all U.S. adults (6). In addition, AI/ANs are twice as likely to have unmet medical needs because of cost (7). AI/ANs also have the highest poverty rate (30%), which is twice the national rate and three times the rate for whites among households with children aged <18 years (8), suggesting that delayed access to medical care and living conditions associated with poverty might contribute to their higher influenza mortality rate.