Changing Patterns in Health Behaviors and Risk Factors Related to Cardiovascular Disease Among American Indians and Alaska Natives

摘要

Objectives . We assessed changes in cardiovascular disease–related health outcomes and risk factors among American Indians and Alaska Natives by age and gender. Methods . We used cross-sectional data from the 1995 to 1996 and the 2005 to 2006 Behavioral Risk Factor Surveillance System. The respondents were 2548 American Indian and Alaska Native women and men aged 18 years or older in 1995–1996 and 11 104 women and men in 2005–2006. We analyzed the prevalence of type 2 diabetes, obesity, hypertension, cigarette smoking, sedentary behavior, and low vegetable or fruit intake. Results. From 1995–1996 to 2005–2006, the adjusted prevalence of diabetes among American Indians and Alaska Natives increased by 26.9%, from 6.7% to 8.5%, and obesity increased by 25.3%, from 24.9% to 31.2%. Hypertension increased by 5%, from 28.1% to 29.5%. Multiple logistic models showed no meaningful changes in smoking, sedentary behavior, or intake of fruits or vegetables. In 2005–2006, 79% of the population had 1 or more of the 6 risk factors, and 46% had 2 or more. Conclusions. Diabetes, obesity, and hypertension and their associated risk factors should be studied further among urban, rural, and reservation American Indian and Alaska Native populations, and effective primary and secondary prevention efforts are critical. Indigenous peoples of the United States are a diverse population of more than 550 federally recognized tribal nations, all of whom have distinct customs, cultures, and languages and reside in diverse geographical territories. 1 , 2 The demographics of indigenous peoples, whom we refer to here as American Indians and Alaska Natives, have changed significantly over the past 50 years. In 1960, 30% of American Indians and Alaska Natives lived in urban areas. 3 Today, however, approximately 66% reside in urban areas, and the remaining 34% continue to live on reservations or in rural areas. 4 – 6 The population is also growing. Between 1990 and 2008, the US American Indian and Alaska Native population increased by 65% from 2.0 to 3.3 million (American Indian and Alaska Native alone 5 ). This growth was achieved through changing patterns of racial self-identification on the part of people with partial or distant American Indian and Alaska Native ancestry coupled with relatively high fertility and improving mortality rates. 3 The population of American Indian and Alaska Native elders is also increasing; the number of American Indians and Alaska Natives aged 55 years and older was 310 000 in 2000 and is projected to increase to 459 000 by 2010. As the American Indian and Alaska Native population grows and ages, several studies have shown that the burden of cardiovascular disease (CVD) and associated risk factors, such as heart disease, stroke, and diabetes, is increasing. 7 , 8 The Strong Heart Study, a longitudinal study of CVD among American Indians in 3 geographic regions, found that the incidence of heart disease in this group has not only surpassed but doubled that of the general US population. 9 Data from the Racial and Ethnic Approaches to Community Health (REACH) initiative funded by the Centers for Disease Control and Prevention found that American Indians and Alaska Natives have the highest prevalence of CVD at 16.4% [95% confidence interval (CI) = 13.6, 19.7] compared with 9.9% (95% CI = 8.7, 11.3) in Blacks, 7.4% (95% CI = 6.0, 9.1) in Hispanics, and 7.5% (95% CI = 5.6, 10.1) in Asians. 10 Aggregate data from the Indian Health Service (IHS) from 1989 to 1991 and 1996 to 1998 show that the CVD mortality rate among American Indians and Alaska Natives increased by 16%, whereas this rate declined in all other racial/ethnic minorities in the United States and in the US non-Hispanic White population. 11 , 12 The average annual percentage change in CVD mortality rates was 0.4 for American Indian and Alaska Natives compared with –1.8 for all races in the United States, including the US White population. 11 , 12 Whereas prior studies have laid the foundation for our knowledge about CVD in American Indians and Alaska Natives, these studies were limited by some or all of the following factors. Few studies used national samples or assessed the extent to which health behaviors and CVD risk factors have changed among American Indians and Alaska Natives over time. Even fewer studies have examined subgroup differences, specifically between men and women or by age groups, region, or sociodemographic status. IHS data, the source of data for many studies, include mostly rural and reservation American Indians and Alaska Natives. Although limited information is known about differences among urban, rural, and reservation populations, some studies have suggested that there are important differences in lifestyles and health outcomes among these populations. 13 , 14 Examining regional differences of both urb