Invited commentary: Cardiovascular mortality in American Indians: paradox explained?

AKT1 polymorphisms are associated with risk for metabolic syndrome

Converging lines of evidence suggest that AKT1 is a major mediator of the responses to insulin, insulin-like growth factor 1 (IGF1), and glucose. AKT1 also plays a key role in the regulation of both muscle cell hypertrophy and atrophy. We hypothesized that AKT1 variants may play a role in the endophenotypes that make up metabolic syndrome. We studied a 12-kb region including the first exon of the AKT1 gene for association with metabolic syndrome-related phenotypes in four study populations [FAMUSS cohort (n = 574; age 23.7 ± 5.7 years), Strong Heart Study (SHS) (n = 2,134; age 55.5 ± 7.9 years), Dynamics of Health, Aging and Body Composition (Health ABC) (n = 3,075; age 73.6 ± 2.9 years), and Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) (n = 175; age 40–65 years)]. We identified a three SNP haplotype that we call H1, which represents the ancestral alleles at the three loci and H2, which represents the derived alleles at the three loci. In young adult European Americans (FAMUSS), H1 was associated with higher fasting glucose levels in females. In middle age Native Americans (SHS), H1 carriers showed higher fasting insulin and HOMA in males, and higher BMI in females. In older African-American and European American subjects (Health ABC) H1 carriers showed a higher incidence of metabolic syndrome. Homozygotes for the H1 haplotype showed about twice the risk of metabolic syndrome in both males and females (p < 0.001). In middle-aged European Americans with insulin resistance (STRRIDE) studied by intravenous glucose tolerance test (IVGTT), H1 carriers showed increased insulin resistance due to the Sg component (p = 0.021). The 12-kb haplotype is a risk factor for metabolic syndrome and insulin resistance that needs to be explored in further populations.

Smoking cessation and prevention: an urgent public health priority for American Indians in the Northern Plains

OBJECTIVE

The purpose of this study was to compare the prevalence of cigarette smoking and smoking cessation among American Indians living on or near Montana's seven reservations to those of non-Indians living in the same geographic region.

METHODS

Data for Montana Behavioral Risk Factor Surveillance System (BRFSS) respondents (n = 1,722) were compared to data from a BRFSS survey of American Indians living on or near Montana's seven reservations in 1999 (n = 1,000). Respondents were asked about smoking and smoking cessation as well as cardiovascular disease (CVD) and selected risk factors. Quit ratios were calculated for both groups.

RESULTS

American Indians were more likely to report current smoking (38%) than non-Indians (19%; p < 0.001). Thirty-seven percent of Indian respondents with CVD risk factors reported current smoking, compared with 17% of non- Indians with CVD risk factors. However, there was no significant difference in reported smoking rates between Indians (21%) and non-Indians (27%) with a history of CVD. Indian smokers were more likely to report quitting for one or more days in the past year (67%), compared with non-Indians (43%). Quit ratios were significantly lower among Indians (43%) than among non-Indians (65%).

CONCLUSIONS

High smoking rates in Indians, particularly among those with other CVD risk factors, demonstrate an urgent need for culturally sensitive smoking cessation interventions among Northern Plains Indians and highlight the need for the Surgeon General's focus on smoking in minority populations.

Cardiovascular disease and risk factors in Montana American Indians and non-Indians

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death for both American Indian and non-Indian adults. Few published studies have compared the prevalence of CVD and related risk factors in Indians to that in non-Indians in the same geographic area.

OBJECTIVE

To compare CVD and risk factors in American Indian and non-Indian populations in Montana.

METHODS

Adult American Indians (n=1000) living on or near Montana's seven reservations and non-Indian (n=905) Montanans statewide were interviewed through the 1999 Behavioral Risk Factor Surveillance Survey (BRFSS).

RESULTS

Indians aged > or =45 years reported a significantly higher prevalence of CVD compared to non-Indians (18% vs 10%). In persons aged 18-44 years, Indians were more likely to report hypertension (15% vs 10%), obesity (29% vs 12%), and smoking (42% vs 24%) compared to non-Indians. For persons aged > or =45 years, Indians reported higher rates of diabetes (24% vs 9%), obesity (38% vs 16%), and smoking (32% vs 13%) compared to non-Indians. Non-Indians aged > or =45 years reported having been diagnosed with high cholesterol more frequently than did Indians (32% vs 24%).

CONCLUSIONS

Both Indians and non-Indians in Montana reported a substantial burden of CVD. The CVD risk patterns differ in the two populations. Prevention programs should be tailored to the risk burdens in these communities with particular emphasis on smoking cessation and the prevention of obesity.

The public health epidemiology of type 2 diabetes in children and adolescents: a case study of American Indian adolescents in the Southwestern United States

Type 2 diabetes among children and adolescents is a newly recognized disease in the United States. Because obesity and physical inactivity are increasing in children and adolescents, the prevalence of pediatric type 2 diabetes may increase and eventually become an important cause of adult morbidity and mortality. Data on type 2 diabetes in adolescents aged 15-19 years were compared between two sources: systematic population screening of the Gila River Indian Community by the National Institutes of Health (NIH), and reported cases by the Indian Health Service (IHS) from clinics in the Southwestern US. The current NIH estimate of prevalence of type 2 diabetes was much higher than the IHS estimate (5.1% vs. 0.46%). Both data sources, however, suggest a secular increase in prevalence between 1986 and 1996-97. These data are used to discuss the principles, applications, and challenges for accurate epidemiologic assessment of type 2 diabetes in children and adolescents.