Analysis of ancient DNA from a prehistoric Amerindian cemetery.
(9/2099)
The Norris Farms No. 36 cemetery in central Illinois has been the subject of considerable archaeological and genetic research. Both mitochondrial DNA (mtDNA) and nuclear DNA have been examined in this 700-year-old population. DNA preservation at the site was good, with about 70% of the samples producing mtDNA results and approximately 15% yielding nuclear DNA data. All four of the major Amerindian mtDNA haplogroups were found, in addition to a fifth haplogroup. Sequences of the first hypervariable region of the mtDNA control region revealed a high level of diversity in the Norris Farms population and confirmed that the fifth haplogroup associates with Mongolian sequences and hence is probably authentic. Other than a possible reduction in the number of rare mtDNA lineages in many populations, it does not appear as if European contact significantly altered patterns of Amerindian mtDNA variation, despite the large decrease in population size that occurred. For nuclear DNA analysis, a novel method for DNA-based sex identification that uses nucleotide differences between the X and Y copies of the amelogenin gene was developed and applied successfully in approximately 20 individuals. Despite the well-known problems of poor DNA preservation and the ever-present possibility of contamination with modern DNA, genetic analysis of the Norris Farms No. 36 population demonstrates that ancient DNA can be a fruitful source of new insights into prehistoric populations. (+info)
Plasma leptin concentrations in Pima Indians living in drastically different environments.
(10/2099)
OBJECTIVE: Plasma leptin, an important signal for the regulation of energy stores, is known to be influenced by many hormonal factors, but may also be affected by behavioral and environmental factors. The purpose of this study was to investigate the impact of lifestyle (diet composition, level of physical activity) on plasma leptin concentrations among Pima Indians living in drastically different environments. RESEARCH DESIGN AND METHODS: We studied 224 Mexican Pima Indians (115 women, 109 men) living a traditional lifestyle in a remote, mountainous area of northwest Mexico and 418 U.S. Pima Indians (281 women, 137 men) living a North American lifestyle on the Gila River Indian Reservation in Arizona. We hypothesized that the absolute value of leptin would be lower in Mexican Pima Indians because of their lower percent body fat, but could be further influenced by their lifestyle, independent of body composition. RESULTS: Leptin concentration (enzyme-linked immunosorbent assay [ELISA]) was strongly correlated with percent fat (bioimpedance) in Mexican Pima Indians (r = 0.83, P < 0.0001) and U.S. Pima Indians (r = 0.86, P < 0.0001). Among U.S. Pima Indians, independent of percent fat, subjects with type 2 diabetes had lower leptin than nondiabetic subjects (difference = 6.9 +/- 1.0 ng/ml, P < 0.002). Among nondiabetic subjects, Mexican Pima Indians had lower absolute leptin concentrations than U.S. Pima Indians, but higher after adjustment for percent body fat, waist circumference, age, and sex. In a subset of 70 pairs of subjects matched for sex and percent body fat, leptin concentration was 4.4 +/- 1.0 ng/ml (P < 0.0001) higher in Mexican Pima Indians versus U.S. Pima Indians. CONCLUSIONS: These results suggest that independent of body composition, leptin concentration may be increased by environmental factors, such as a high-carbohydrate diet and a high level of physical activity. (+info)
Prevalence and correlates of the insulin resistance syndrome among Native Americans. The Inter-Tribal Heart Project.
(11/2099)
OBJECTIVE: The clustering of factors characterizing the insulin resistance syndrome has not been assessed among Native Americans, a population at high risk for diabetes and cardiovascular disease. We examined the distribution and correlates of the insulin resistance syndrome among individuals in three Chippewa and Menominee communities in Wisconsin and Minnesota. RESEARCH DESIGN AND METHODS: Cross-sectional data from 488 men and 822 women ages > or = 25 years in the Inter-Tribal Heart Project (1992-1994) were included. The clustering of each individual trait (hypertension, diabetes, high triglycerides, and low HDL cholesterol) with the other traits and the association of the number of traits with measures of adiposity and insulin levels were examined. RESULTS: Among the men, 40.4, 32.6, 17.4, and 9.6% had none, one, two, or at least three of the four traits, respectively; among the women, the respective percentages were 53.2, 25.6, 15.3, and 6.0%. The percentage of individuals with each particular trait significantly increased (P < 0.01) among those with none, one, or at least two other syndrome traits. Having more syndrome traits was significantly related (P < 0.001) to higher BMI, conicity index, waist circumference, and waist-to-hip and waist-to-thigh ratios. Among individuals with normal glucose levels, having more syndrome traits was significantly related (P < or = 0.05) to higher fasting insulin levels after adjusting for age and measures of adiposity, although associations were attenuated with adjustment for either BMI or waist circumference. CONCLUSIONS: Traits characterizing the insulin resistance syndrome were found to be clustered to a significant degree among Native Americans in this study. Comprehensive public health efforts are needed to reduce adverse levels of these risk factors in this high-risk population. (+info)
Effect of glycemia on mortality in Pima Indians with type 2 diabetes.
(12/2099)
The effect of plasma glucose concentration on overall and cause-specific mortality was examined in 1,745 Pima Indians (725 men, 1,020 women) > or = 15 years old with type 2 diabetes. During a median follow-up of 10.6 years (range 0.1-24.8), 533 subjects (275 men, 258 women) died; 113 of the deaths were attributable to cardiovascular disease, 96 to diabetes-related diseases (diabetic nephropathy for 92 of these), 249 to other natural causes, and 75 to external causes. After adjusting for age, sex, duration of diabetes, and BMI in a generalized additive proportional hazards model, higher baseline 2-h postload plasma glucose concentration predicted deaths from cardiovascular disease (P = 0.007) and diabetes-related diseases (P = 0.003), but not from other natural causes (P = 0.73). An increment of 5.6 mmol/l (100 mg/dl) in the 2-h plasma glucose concentration was associated with 1.2 times (95% CI 1.1-1.4) the death rate from cardiovascular disease, 1.3 times (95% CI 1.1-1.5) the death rate from diabetes-related diseases, and almost no change in the death rate from other natural causes (rate ratio = 1.0; 95% CI 0.94-1.1). In Pima Indians with type 2 diabetes, higher plasma glucose concentration predicts deaths from cardiovascular and diabetes-related diseases but has little or no effect on deaths from other natural or external causes. (+info)
A social systems model of hospital utilization.
(13/2099)
A social systems model for the health services system serving the state of New Mexico is presented. Utilization of short-term general hospitals is viewed as a function of sociodemographic characteristics of the population and of the supply of health manpower and facilities available to that population. The model includes a network specifying the causal relationships hypothesized as existing among a set of social, demographic, and economic variables known to be related to the supply of health manpower and facilities and to their utilization. Inclusion of feedback into the model as well as lagged values of physician supply variables permits examination of the dynamic behavior of the social system over time. A method for deriving the reduced form of the structural model is presented along with the reduced-form equations. These equations provide valuable information for policy decisions regarding the likely consequences of changes in the structure of the population and in the supply of health manpower and facilities. The structural and reduced-form equations have been used to predict the consequences for one New Mexico county of state and federal policies that would affect the organization and delivery of health services. (+info)
Formative research in a school-based obesity prevention program for Native American school children (Pathways).
(14/2099)
This paper describes how formative research was developed and implemented to produce obesity prevention interventions among school children in six different Native American nations that are part of the Pathways study. The formative assessment work presented here was unique in several ways: (1) it represents the first time formative research methods have been applied across multiple Native American tribes; (2) it is holistic, including data collection from parents, children, teachers, administrators and community leaders; and (3) it was developed by a multi-disciplinary group, including substantial input from Native American collaborators. The paper describes the process of developing the different units of the protocol, how data collection was implemented and how analyses were structured around the identification of risk behaviors. An emphasis is placed on describing which units of the formative assessment protocol were most effective and which were less effective. (+info)
The epidemic of obesity in American Indian communities and the need for childhood obesity-prevention programs.
(15/2099)
American Indians of all ages and both sexes have a high prevalence of obesity. The high prevalence of diabetes mellitus in American Indians shows the adverse effects that obesity has in these communities. Obesity has become a major health problem in American Indians only in the past 1-2 generations and is believed to be associated with the relative abundance of high-fat foods and the rapid change from active to sedentary lifestyles. Intervention studies are urgently needed in American Indian communities to develop and test effective strategies for weight reduction. The poor success rate of adult obesity treatment programs in the general population points to the need to develop prevention approaches aimed toward children. Because eating and physical activity practices are formed early in life and may be carried into adulthood, prevention programs that encourage increased physical activity and healthful eating habits targeted toward young people need to be developed and tested. To be most effective, interventions must be developed with full participation of the American Indian communities. (+info)
Practicing participatory research in American Indian communities.
(16/2099)
The purpose of this article is to explore the historical issues that affect research in American Indian communities and examine the implications of these issues as they relate to culturally sensitive, respectful, and appropriate research with this population. Methods include review and analysis of the literature and examination of our collective experience and that of our colleagues. Recommendations are given for conducting culturally sensitive, participatory research. We conclude that research efforts must build on the establishment of partnerships between investigators and American Indian communities to ensure accurate findings and analyses and to implement culturally relevant benefits. (+info)