TUESDAY, Oct. 4, 2005 (HealthDay News) -- Death rates from heart disease and stroke among Native Americans in Montana are significantly higher than those for whites.
Even more troubling, disparities between the two groups have widened in the decade between 1991 and 2001, according to a study in the Oct. 4 issue of Circulation.
An increasing prevalence of cardiovascular risk factors seems to be responsible for the figures, the researchers said.
"The prevalence of smoking, overweight and obesity combined, all helped drive it up here in the Plains," said study author Todd S. Harwell, chief of the chronic disease prevention and health promotion bureau at the Montana Department of Public Health and Human Services in Helena. The prevalence of smoking in that region is more than 30 percent, he noted.
"The study confirms what has been observed by others, that American Indians have a high cardiovascular disease burden, specifically heart disease and stroke mortality in Montana," added Dr. Gregory Burke, chairman of the department of public health sciences at Wake Forest University School of Medicine. "The high rates of heart disease and stroke in American Indians are likely mediated by even more adverse levels of cardiovascular risk factors, especially diabetes and smoking."
Findings such as these are shifting public health priorities.
"Indian health services and tribes are getting communities aware of the cardiovascular disease and risk," Harwell said. "It has become the priority over the past decade."
Burke emphasized: "This paper reminds us that we need to increase our efforts at cardiovascular disease prevention in 'Indian Country.' Specifically, tailored efforts to deal with the epidemic of obesity and diabetes, as well as the high rates of cigarette smoking, are needed."
Studies done over the last three to four decades had suggested that Native Americans and Alaska Natives had a lower risk for heart disease, Harwell said. But in the 1980s, the Strong Heart Study, conducted in Arizona, Oklahoma, and North and South Dakota, dispelled that myth, finding that death rates from heart disease between 1984 and 1988 were two times higher in Indians from North and South Dakota compared to the general U.S. population. Mortality rates in Arizona and Oklahoma were similar to the overall U.S. rates.
"The issue is where you look in the United States," Harwell said. "If you look in the Southwest, the cardiovascular mortality rates are generally lower for American Indians, but the prevalence for smoking and cardiovascular risk factors are also lower. It goes hand in hand."
For the new study, Harwell and his colleagues analyzed 75,993 death certificates issued in Montana from 1991 to 1995 and from 1996 to 2000 to determine different causes of death for American Indians and for whites.
Overall mortality rates were "strikingly higher" for American Indians as compared to whites, the authors stated. Between 1996 and 2000, for instance, the mortality rate for American Indians was 1,317 per 100,000 vs. 831 per 100,000 for whites.
While the number of deaths from heart disease declined considerably for whites (237 to 216 per 100,000) in Montana over the past decade, it has declined less in American Indians (326 to 283 per 100,000).
Stroke deaths declined significantly in whites (64 to 60 per 100,000), but rose in American Indians (80 to 81 per 100,000) during the same time period.
Indian men under the age of 65 were much more likely to die of heart disease and stroke: 45 percent of American Indian men and 29 percent of American Indian women who died of heart disease during this time were under 65, compared to 21 percent of white men and 8 percent of white women.
Thirty-six percent of American Indian men and 28 percent of American Indian women who died of stroke were under the age of 65, compared with 11 percent of white men and 7 percent of white women.
At the same time, in 1999, Native Americans in Montana had a higher prevalence of risk factors for cardiovascular disease than did whites. The prevalence of two or more risk factors for heart disease in American Indian adults rose from 34 percent in 1999 to 44 percent in 2003.
The risks for heart disease and stroke among American Indians in Montana were similar to those found in American Indians in the Dakotas.
The study highlights the importance of viewing data from a regional perspective, the researchers said.
"If state health departments and tribal health organizations only look at national data, they could get misleading data about problems in their community," Harwell said. "Going down and looking at the state level or regional level is important so they know how the issue affects them directly."
Given small populations of American Indians, this can sometimes be a challenge. "The Indian population here is about 60,000," Harwell said. "There's a balance between how far down can you go and still have reliable estimates."
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