Relation of insulin resistance to markers of preclinical cardiovascular disease: the Strong Heart Study.

BACKGROUND AND AIMS: To investigate whether insulin-resistance influences echocardiographic markers of preclinical disease, independent of significant confounders. METHODS AND RESULTS: We examined 1,471 (59 +/- 8 years) non-diabetic individuals (WHO criteria) with available echocardiograms from the Strong Heart Study cohort. Among them, 530 subjects had arterial hypertension (62% on medications), 152 had impaired glucose tolerance (GT) and 460 were normotensive, non-obese with normal GT. Insulin resistance was estimated by the Homeostasis Model Assessment (HOMA). LV mass, systolic function measured at the endocardium and the midwall (also correcting for circumferential wall stress) and arterial compliance (stroke volume/pulse pressure as a percent of predicted from body weight, age and heart rate [delta %SV/PP]) were measured by echocardiography, as prognostically validated markers of preclinical disease. HOMA-index was related positively to body mass index (BMI), waist/hip ratio (WHR), blood pressure, left ventricular (LV) mass, and negatively to arterial compliance (all p < 0.005) in the whole population, as well as in separate normotensive or hypertensive groups. In multiple regression models, relation of HOMA-index with the markers of risk was adjusted for age, sex, WHR, body mass index, presence of hypertension and number of antihypertensive medications. In this analysis, neither LV mass nor indices of systolic function were independently related to HOMA-index. In contrast, HOMA-index maintained a significant negative association with delta %SV/PP, independent of demographics, hypertension, treatment and body fat distribution. Also, HOMA-index maintained an independent relation with LV mass, when WHR and BMI were not included in the regression model. CONCLUSIONS: After accounting for relevant biological covariates, including body mass and fat distribution, insulin-resistance measured by HOMA is not an independent correlate of LV mass and function, but negatively influences arterial compliance.

Evidence for joint action of genes on diabetes status and CVD risk factors in American Indians: the strong heart family study.

OBJECTIVES: Previous research among American Indians of the strong heart family study (SHFS) has demonstrated significant heritabilities for CVD risk factors and implicated diabetes as an important predictor of several of the phenotypes. Moreover, we recently demonstrated that genetic effects on CVD risk factors differed in diabetic and nondiabetic individuals. In this paper, we investigated whether a significant genetic influence on diabetes status could be identified, and whether there is evidence for joint action of genes on diabetes status and related CVD risk factors. METHODS AND RESULTS: Approximately 950 men and women, age 18 or older, in 32 extended families, were examined between 1997 and 1999. We estimated the effects of genes and environmental covariates on diabetes status using a threshold model and a maximum likelihood variance component approach. Diabetes status exhibited a residual heritability of 22% (h2=0.22). We also estimated the genetic and environmental correlations between diabetes susceptibility and eight risk factors for CVD. All eight CVD risk factors displayed significant genetic correlations with diabetes status (BMI (rhoG=0.55), fibrinogen (rhoG=0.40), HDL-C (rhoG=-0.37), ln triglycerides (rhoG=0.65), FAT (rhoG=0.38 ), PAI-1 (rhoG=0.67), SBP (rhoG=0.57), and WHR (rhoG=0.58)). Three of eight traits (HDL-C (rhoE=-0.32), ln triglycerides (rhoE=0.33), and fibrinogen (rhoE=0.20)) displayed significant environmental correlations with diabetes status. CONCLUSIONS: These findings suggest that in the context of a high prevalence of diabetes, still unidentified diabetes genes may play an important role in influencing variation in CVD risk factors.

Prevalence and correlates of mitral valve prolapse in a population-based sample of American Indians: the Strong Heart Study.

PURPOSE: Mitral valve prolapse is heritable and occurs frequently in the general population despite associations with mitral regurgitation and infective endocarditis, suggesting that selective advantages might be associated with mitral valve prolapse. SUBJECTS AND METHODS: Clinical examination and 2-dimensional and color Doppler echocardiography were performed in 3340 American Indian participants in the Strong Heart Study. RESULTS: Mitral valve prolapse (clear-cut billowing of one or both mitral leaflets across the mitral anular plane in 2-dimensional parasternal long-axis recordings or >2-mm late systolic posterior displacement of mitral leaflets by M mode) occurred in 37 (1.8%) of 2077 women and 20 (1.6%) of 1263 men (P = 0.88); 32 (3.5%) of 907 patients with normal glucose tolerance, 11 (2.3%) of 486 patients with impaired glucose tolerance, and 13 (0.7%) of 1735 patients with diabetes (P <0.0001). Participants with mitral valve prolapse had lower mean (+/- SD) body mass index (28 +/- 5 kg/m(2) vs. 31 +/- 6 kg/m(2), P = 0.001) and blood pressure (124/71 +/- 19/10 mm Hg vs. 130/75 +/- 21/10 mm Hg, P <0.05), as well as lower levels of fasting glucose, triglycerides, serum creatinine, and log urine albumin/creatinine ratio (all P <0.001), than did those without mitral valve prolapse, although all subjects were similar in age (60 +/- 8 years). Participants with mitral valve prolapse had lower ventricular septal (0.87 +/- 0.08 cm vs. 0.93 +/- 0.13 cm) and posterior wall thicknesses (0.82 +/- 0.08 cm vs. 0.87 +/- 0.10 cm), mass (38 +/- 7 g/m(2.7) vs. 42 +/- 11 g/m(2.7)), and relative wall thickness (0.33 +/- 0.04 vs. 0.35 +/- 0.05), and increased stress-corrected midwall shortening (all P <0.01). Mitral valve prolapse was associated with a higher prevalence of mild (16 of 57 [28%] vs. 614 of 3283 [19%]) and more severe mitral regurgitation (5 of 57 [9%] vs. 48 of 3283 [1%], P <0.0001). Regression analyses showed prolapse was associated with low ventricular relative wall thickness, high midwall function, and low urine albumin/creatinine ratio, independent of age, sex, body mass index, and diabetes. CONCLUSIONS: Mitral valve prolapse is fairly common and is strongly associated with mitral regurgitation in the general population. However, it is also associated with lower body weight, blood pressure, and prevalence of diabetes; a more favorable metabolic profile and ventricular geometry; and better myocardial and renal function.

Hypertension treatment patterns in American Indians: the strong heart study.

Pharmacologic treatment patterns for hypertensive American Indians from 13 communities in Arizona, Oklahoma, South Dakota, and North Dakota were assessed. Participants (2254 women and 1384 men, aged 48 to 79 years) completed a clinical examination between July 1993 and December 1995. The mean of two blood pressure (BP) measurements and detailed medication histories were obtained. The observed prevalence of hypertension was 46.7% (n=1698). In participants taking antihypertensive medications (n=1114), four principal drug classes were evaluated: diuretics, calcium channel blocking agents, beta-blocking agents, and angiotensin-converting enzyme (ACE) inhibitors. Among treated hypertensive participants, 71.4%, 24.6%, and 4.0% received one, two, and three medications, respectively. Among single drug regimens, ACE inhibitors (n=340) were used most often (49.4%), with calcium channel blocking agents and diuretics accounting for 24.2% and 19.9%, respectively. Although multiple drug class therapies varied, the combination of a diuretic and ACE inhibitor (n=120) accounted for 47.4% of dual therapy use. Hypertension control (SBP < 140 mm Hg, DBP < 90 mm Hg) rates were highest for those on dual therapies (65.4%), followed by participants on single (53.8%) and triple (43.6%) therapies. Among monotherapies, diuretics exhibited the best overall hypertension control rate in both diabetics (63.0%) and nondiabetics (68.0%), versus 47% to 61% for other remaining agents. The frequent use of ACE inhibitors, used singly or in combination, reflects the high prevalence of diabetes among American Indians. ACE inhibitors, combined with diuretics, were particularly useful in achieving BP control in this population.

The Aberdeen Indian Health Service infant mortality study: design, methodology, and implementation.

Of all Indian Health Service areas, the Aberdeen Area has consistently had the highest infant mortality rate. Among some tribes in this area the rate has exceeded 30/ 1000 live birth and half the infant deaths have been attributed to Sudden Infant Death Syndrome,a rate four to five times higher than the national average. The Indian Health Service, Centers for Disease Control and Prevention, National Institute of Child Health and Human Development, and the Aberdeen Area Tribal Chairmen's Health Board collaborated to investigate these high rates with the goals of refining the ascertainment of the causes of death, improving cause-specific infant mortality rates and identifying factors contributing to the high rates. Ten of the 19 tribes or tribal communities, representing 66%of the area population, participated in a 4-year prospective case-control study of infants who died after discharge from the hospital. Infant care practices and socio-demographic, economic, medical, health care, and environmental factors were examined. The study included parental interviews, death scene investigations, autopsies, neuropathology studies, medical chart abstractions, blood cotinine assays, and a surveillance system for infant deaths. Controls were the previous and subsequent infants born on the case mother's reservation. From December 1,1992 until November 30,1996,72 infant deaths were investigated. This report describes the study methods and the model employed for involving the community and multiple agencies to study the problem of infant mortality among Northern Plains Indians. Data gathered during the investigations are being analyzed and will be published at a later date.

Spirometry reference values for American Indian adults: results from the Strong Heart Study.

STUDY OBJECTIVE: To derive spirometry normative values from a large population of American Indian adults and compare them to reference values for white adults. DESIGN: Pulmonary function was assessed using spirometry in participants of the Strong Heart Study, a multicenter, community-based, prospective study of cardiovascular risk factors and disease in American Indians, utilizing American Thoracic Society guidelines and a vigorous quality assurance program. SETTING: Central Arizona, southwestern Oklahoma, central South Dakota, and northeastern North Dakota. PARTICIPANTS: Acceptable spirometry results were obtained from 1,619 women and 1,005 men aged 45 to 74 years. RESULTS: Internal reference values and normal ranges for FEV(1), FVC, and the FEV(1)/FVC ratio were derived from a healthy subgroup of 253 women and 190 men, identified by excluding participants with factors associated with a lower FEV(1). Ten percent of the entire cohort (269 of 2,624 subjects) had airways obstruction, as defined by an FEV(1)/FVC below the lower limit of the normal (LLN) using the internal reference equations. After allowing for measurement "noise," 31 participants were below the LLN using reference equations for white adults from the large National Health and Nutrition Examination Study (NHANES) III study but were normal using the internal reference equations (1.3% false-positive), while 27 participants were classified as normal using NHANES III equations but had airways obstruction using the internal reference equations (1.2% false-negative). Similarly low misclassification rates were seen for a low FVC (prevalence, 17.6%). CONCLUSION: For clinical purposes, NHANES III spirometry reference equations for white adults may be used when testing American Indian women and men aged 45 to 74 years.

Reference values for echocardiographic measurements in urban and rural populations of differing ethnicity: the Strong Heart Study.

Discrepancies in reported reference values for left ventricular (LV) dimensions and mass may be due to imaging errors with early echocardiographic methods or effects of subject characteristics and inclusion criteria. To determine whether contemporary echocardiographic methods provide stable normal limits for left ventricular measurements in different populations, M-mode/2-dimensional echocardiography was applied in 176 American Indian participants in the Strong Heart Study and 237 New York City residents who were clinically normal. No consistent difference in any measure of LV size or function existed between populations. Upper normal limits (98th percentile) for LV mass were 96 g/m(2) in women and 116 g/m(2) in men and 3.27 cm/m for LV chamber diameter normalized for height. Thus contemporary M-mode/2D echocardiography provides reference ranges for LV measurements that approximate necropsy measurements and have acceptable stability in apparently normal white, African-American/Caribbean, and American Indian populations.

The impact of diabetes on left ventricular filling pattern in normotensive and hypertensive adults: the Strong Heart Study.

OBJECTIVES: We sought to determine the effect of diabetes mellitus (DM) on left ventricular (LV) filling pattern in normotensive (NT) and hypertensive (HTN) individuals. BACKGROUND: Diastolic abnormalities have been extensively described in HTN but are less well characterized in DM, which frequently coexists with HTN. METHODS: We analyzed the transmitral inflow velocity profile at the mitral annulus in four groups from the Strong Heart Study: NT-non-DM (n = 730), HTN-non-DM (n = 394), NT-DM (n = 616) and HTN-DM (n = 671). The DM subjects were further divided into those with normal filling pattern (n = 107) and those with abnormal relaxation (AbnREL) (n = 447). RESULTS: The peak E velocity was lowest in HTN-DM, intermediate in NT-DM and HT-non-DM and highest in the NT-non-DM group (p < 0.001), with a reverse trend seen for peak A velocity (p < 0.001). In multivariate analysis, E/A ratio was lowest in HTN-DM and highest in NT-non-DM, with no difference between NT-DM and HTN-non DM (p < 0.001). Likewise, mean atrial filling fraction and deceleration time were highest in HTN-DM, followed by HTN-non-DM or NT-DM and lowest in NT-non-DM (both p < 0.05). Among DM subjects, those with AbnREL had higher fasting glucose (p = 0.03) and hemoglobin A1C (p = 0.04). CONCLUSIONS: Diabetes mellitus, especially with worse glycemic control, is independently associated with abnormal LV relaxation. The severity of abnormal LV relaxation is similar to the well-known impaired relaxation associated with HTN. The combination of DM and HTN has more severe abnormal LV relaxation than groups with either condition alone. In addition, AbnREL in DM is associated with worse glycemic control.

Relationship of impaired glucose tolerance to left ventricular structure and function: The Strong Heart Study.

BACKGROUND: We have identified increased left ventricular (LV) mass, wall thickness, relative wall thickness, and reduced systolic function in diabetic individuals after adjusting for blood pressure and body mass index. However, the cardiovascular correlates of impaired glucose tolerance (IGT), a precursor of diabetes, are unknown. METHODS: We compared LV measurements between 457 American Indian participants in the Strong Heart Study with IGT (34% men) by World Health Organization criteria and 888 participants (49% men) with normal glucose tolerance. RESULTS: Participants with IGT were older (60 vs 59 years, P < .01), more overweight (body mass index, 32 +/- 6 vs 29 +/- 5 g/m(2)), and had higher systolic blood pressure (129 +/- 20 vs 124 +/- 18 mm Hg, P < .001) and heart rate (67 +/- 10 vs 66 +/- 11 beats/min, P = .011). In univariate analyses, women but not men with IGT had higher LV mass (mean, 150 vs 138 g, P < .001) and cardiac index (2.6 vs 2.5 L/min/m(2), P < .05). LV wall thicknesses and relative wall thickness were greater in women and men with IGT. Regression analysis, adjusting for multiple covariates in the entire study population, identified independent associations of IGT with higher LV relative wall thicknesses, LV mass/height(2.7), and cardiac output/height(1.83). CONCLUSIONS: IGT is associated with increased LV wall thickness, mass, and cardiac output independent of effects of relevant covariates.

Separate and joint effects of systemic hypertension and diabetes mellitus on left ventricular structure and function in American Indians (the Strong Heart Study).

Although the association of systemic hypertension (SH) with diabetes mellitus (DM) is well established, the cardiac features and hemodynamic profile of patients with SH and DM diagnosed by American Diabetes Association criteria have not been elucidated. To address this issue, echocardiograms were analyzed in 1,025 American Indian participants of the Strong Heart Study with neither DM nor SH, 642 with DM alone, 614 with SH alone, and 874 with SH and DM. In analyses that adjusted for age, gender, body mass index, and heart rate, DM and SH were associated with increased left ventricular (LV) wall thicknesses, with the greatest impact of DM on LV relative wall thickness and of the combination of DM and SH on LV mass (both p <0.001). LV fractional shortening was reduced with SH and SH + DM, midwall shortening was reduced with DM, SH, and their combination, and was reduced in both diabetic groups compared with their nondiabetic counterparts (p <0.001). DM alone was associated with lower measures of LV pump performance (stroke volume, cardiac output, and their indexes) than SH alone. Pulse pressure/stroke index, an indirect measure of arterial stiffness, was elevated in participants with DM or SH alone and most in those with both conditions. There were progressive increases from the reference group to DM alone, SH alone, and DM + SH with regard to prevalences of LV hypertrophy (12% to 19%, 29% and 38%) and subnormal LV myocardial function (7% to 10%, 11% and 18%, both p <0.001). In conclusion, DM and SH each have adverse effects on LV geometry and function, and the combination of SH and DM results in the greatest degree of LV hypertrophy, myocardial dysfunction, and arterial stiffness.

A population-based assessment of left ventricular systolic dysfunction in middle-aged and older adults: the Strong Heart Study.

BACKGROUND: Although clinical congestive heart failure (CHF) is increasingly common, few data document the prevalence and correlates of underlying left ventricular (LV) systolic dysfunction (D) in population-based samples. METHODS: Echocardiography was used in the second Strong Heart Study (SHS) examination to identify mild and severe LVD (LV ejection fraction [EF] 40%-54% and <40%, respectively) in 3184 American Indians. RESULTS: Mild and severe LVD were more common in men than women (17.4% vs 7.2% and 4.7% vs 1.8%) and in diabetic than nondiabetic participants (12.7% vs 9.1% and 3.5% vs 1.6%). Stepwise increases were observed from participants with normal EF to those with mild and severe LVD in age (mean 60 vs 61 and 63 years, P <.001), prevalence of overt CHF (2% vs 6% and 28%) and definite coronary heart disease (3% vs 11% and 32%), systolic pressure (129 vs 135 and 136 mm Hg), serum creatinine level (0.98 vs 1.34 and 2.16 mg/dL), and log urinary albumin/creatinine level (3.2 vs 3.7 and 4.7); a negative relation was seen with body mass index (31.1 vs 31.0 and 28.4 kg/m(2)) (all P <.001). In multivariate analyses lower LVEFs were independently associated with clinical CHF and coronary heart disease, lower myocardial contractility, male sex, hypertension, overweight, arterial stiffening (higher pulse pressure/stroke volume) and renal dysfunction (higher serum creatinine level), higher LV mass, and lower relative wall thickness. CONCLUSIONS: LVD, present in approximately 14% of middle-aged to elderly adults, is independently associated with overt heart failure and coronary heart disease, male sex, hypertension, overweight, arterial stiffening, and renal target organ damage and, less consistently, with older age and diabetes.

Relations of stroke volume and cardiac output to body composition: the strong heart study.

BACKGROUND: Although cardiac output (CO) plays the vital role of delivering nutrients to body tissues, few data are available concerning the relations of stroke volume (SV) and CO to body composition in large population samples. METHODS AND RESULTS: Doppler and 2D echocardiography and bioelectric impedance in 2744 Strong Heart Study participants were used to calculate SV and CO and to relate them to fat-free body mass (FFM), adipose mass, and demographic variables. Both SV and CO were higher in men than women and in overweight than normal-weight individuals, but these differences were diminished or even reversed by normalization for FFM or body surface area. In both sexes, SV and CO were more strongly related to FFM than adipose mass, other body habitus measures, arterial pressure, diabetes, or age. In multivariate analyses using the average of Doppler and left ventricular SV to minimize measurement variability, FFM was the strongest correlate of SV and CO; other independent correlates were adipose mass, systolic pressure, diabetes, age, and use of digoxin and calcium channel and beta-blockers. CONCLUSIONS: In a population-based sample, SV and CO are more strongly related to FFM than other variables; increased FFM may be the primary determinant of increased SV and CO in obesity.

Prevalence and correlates of mitral regurgitation in a population-based sample (the Strong Heart Study).

Evidence suggesting that mitral regurgitation (MR) may be induced by appetite suppressant medications heightens the importance of understanding the prevalence and correlates of MR, especially its relation to obesity, in population-based samples. MR was assessed by color Doppler echocardiography in 3,486 American Indian participants in the Strong Heart Study. Mild (1+) MR was present in 19.2%, moderate (2+) MR in 1.6%, moderately severe (3+) in 0.3%, and severe (4+) in 0.2% of participants. In univariate analyses, MR was unrelated to gender, diabetes, or lipid levels, but was more frequent in North/South Dakota (28.3%) than in Oklahoma (21.6%) or Arizona (14.3%) (p <0.001). MR was related to lower body mass index (BMI) (p <0.001), older age (p <0.001), higher systolic blood pressure (p = 0.003), higher serum creatinine (p <0.001), and higher urine albumin/creatinine ratio (p <0.001). In multivariate analyses, the presence and severity of MR were independently associated with higher serum creatinine, lower BMI, mitral stenosis, prior myocardial infarction, female gender, mitral valve prolapse and, variably, older age. In conclusion, MR, mostly mild, is detected by color Doppler echocardiography in >20% of middle-aged and older adults. MR is independently associated with female gender, lower BMI, older age, and renal dysfunction, as well as with prior myocardial infarction, mitral stenosis, and mitral valve prolapse. It is not related to dyslipidemia or diabetes.

Congestive heart failure despite normal left ventricular systolic function in a population-based sample: the Strong Heart Study.

In selected clinical series, > or = 50% of adults with congestive heart failure (CHF) do not have left ventricular (LV) systolic dysfunction. Little is known of the prevalence of this phenomenon in population samples. Therefore, clinical examination and echocardiography were used in the second examination of the Strong Heart Study (3,184 men and women, 47 to 81 years old) to identify 95 participants with CHF, 50 of whom had normal LV ejection fraction (EF) (> 54%), 19 of whom had mildly reduced EF (40% to 54%), and 26 of whom had EF < or = 40%. Compared with those with no CHF, participants with CHF and no, mild, or severe decrease in EF had higher creatinine levels (2.34 to 2.85 vs 1.01 mg/dl, p < 0.001) and higher prevalences of diabetes (60% to 70% vs 50%) and hypertension (75% to 96% vs 46%, p < 0.05). Compared with those with no CHF, participants with CHF and normal EF had prolonged deceleration time (233 vs 204 ms, p < 0.05) and a reduced E/A, whereas those with CHF and EF < or = 40% had short deceleration time (158 ms, p < 0.05) and high E/A (1.70, p < 0.001); patients with CHF and normal EF had higher LV mass (98 vs 84 g/m2, p < 0.001) and relative wall thickness (0.37 vs 0.35, p < 0.05) than those without CHF. Patients with CHF with normal EF were, compared with those without CHF or with CHF and EF < or = 40%, disproportionately women (mean 84% vs 63% and 42%, p < 0.001), older (mean 64 vs 60 years and 63 years, respectively, p < 0.01), had higher body mass index (mean 33.1 vs 31.0 and 27.7 kg/m2, p < 0.05), and higher systolic blood pressure (mean 137 vs 130 and 128 mm Hg, both p < 0.05). Thus, in a population-based sample, patients with CHF and normal LV EF were older and overweight, more often women, had renal dysfunction, impaired early diastolic LV relaxation, and concentric LV geometry, whereas patients with CHF and severe LV dysfunction were more often men, had lower body mass index, a restrictive pattern of LV filling, and eccentric LV hypertrophy.

Effects of obesity and body fat distribution on lipids and lipoproteins in nondiabetic American Indians: The Strong Heart Study.

OBJECTIVES: To examine the relationship between obesity and lipoprotein profiles and compare the effects of total obesity and central adiposity on lipids/lipoproteins in American Indians. RESEARCH METHODS AND PROCEDURES: Participants were 773 nondiabetic American Indian women and 739 men aged 45 to 74 years participating in the Strong Heart Study. Total obesity was estimated using body mass index (BMI). Central obesity was measured as waist circumference. Lipoprotein measures included triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein AI (apoAI), and apolipoprotein B (apoB). Partial and canonical correlation analyses were used to examine the associations between obesity and lipids/ lipoproteins. RESULTS: Women were more obese than men in Arizona (median BMI 32.1 vs. 29.2 kg/m2) and South Dakota and North Dakota (28.3 vs. 28.0 kg/m2), but there was no sex difference in waist circumference. Men had higher apoB and lower apoAI levels than did women. In women, when adjusted for center, gender, and age, BMI was significantly related to HDL cholesterol (r = -0.24, p < 0.001). There was a significant but weak relation with apoAI (r = -0.14, p < 0.001). Waist circumference was positively related to triglycerides (r = 0.14, p < 0.001) and negatively related to HDL cholesterol (r = -0.23, p < 0.001) and apoAI (r = -0.13, p < 0.001). In men, BMI was positively correlated with triglycerides (r = 0.30, p < 0.001) and negatively correlated with HDL cholesterol (r = -0.35, p < 0.001) and apoAI (r = -0.23, p < 0.001). Triglycerides increased with waist circumference (r = 0.30, p < 0.001) and HDL cholesterol decreased with waist circumference (r = -0.36, p < 0.001). In both women and men there was an inverted U-shaped relationship between obesity and waist with LDL cholesterol and apoB. In canonical correlation analysis, waist circumference received a greater weight (0.86) than did BMI (0.17) in women. However, the canonical weights were similar for waist (0.46) and BMI (0.56) in men. Only HDL cholesterol (-1.02) carried greater weight in women, whereas in men, triglycerides (0.50), and HDL cholesterol (-0.64) carried a large amount of weight. All the correlation coefficients between BMI, waist circumference, and the first canonical variable of lipids/lipoproteins or between the individual lipid/lipoprotein variables and the first canonical variable of obesity were smaller in women than in men. Triglycerides and HDL cholesterol showed clinically meaningful changes with BMI and waist circumference in men. All lipid/lipoprotein changes in women in relation to BMI and waist circumference were minimal. DISCUSSION: The main lipoprotein abnormality related to obesity in American Indians was decreased HDL cholesterol, especially in men. Central adiposity was more associated with abnormal lipid/lipoprotein profiles than general obesity in women; both were equally important in men.

Differences in echocardiographic findings and systemic hemodynamics among non-diabetic American Indians in different regions: The Strong Heart Study.

PURPOSE: This study was undertaken to determine whether differences in left ventricular (LV) and systemic hemodynamic findings exist between American Indians in different regions that might contribute to known differences in cardiovascular morbidity rates among American Indians. METHODS: We compared echocardiography results in 290 non-diabetic Strong Heart Study (SHS) participants in Arizona, 595 in Oklahoma and 572 in North/South Dakota (ND/SD). RESULTS: Participants in the 3 regions were similar in age and gender but those in Arizona had the highest body mass indices and lowest heart rates while those in ND/SD had the lowest diastolic blood pressures (BP). In analyses that adjusted for significant covariates, ND/SD participants had larger aortic (Ao) anular, Ao root, and LV chamber size as well as higher cardiac output and lower peripheral resistance, whereas Arizona participants had increased LV wall thickness and mass and reduced LV myocardial contractility. These findings may contribute to the known high rates of cardiovascular events in ND/SD Indians and to the proportionately higher rate of cardiovascular death than of non-fatal cardiovascular events that has been recently documented in Arizona Indians. CONCLUSIONS: Application of echocardiography to non-diabetic SHS participants reveals that LV chamber and arterial size are larger in ND/SD Indians and that LV wall thicknesses and mass are higher and LV myocardial contractility lower in Arizona Indians, possibly contributing to the higher than expected rates of cardiovascular morbidity and mortality among Indians in Arizona.

Low national breast and cervical cancer-screening rates in American Indian and Alaska Native women with diabetes.

BACKGROUND: The cervical cancer mortality rate for American Indian and Alaska Native women is twice that of all races in the United States. To date the only published national breast and cervical cancer-screening rates for American Indian and Alaska Native women are based on self-reported data. When the Indian Health Service (IHS) conducts an annual audit on patients with diabetes, it includes cancer screening. This observational study presents national breast and cervical cancer-screening rates for American Indian and Alaska Native women with diabetes. METHODS: Cancer-screening rates were extracted from the 1995 diabetic audit for the 12 IHS areas. These rates were compared with rates for women without diabetes of the same age, 50 to 69 years, by chart review, at four IHS hospitals in the Aberdeen IHS area. RESULTS: Screening rates for women with diabetes in the 12 areas varied: mammogram (ever) 35% to 78%; clinical breast examination (last year) 28% to 70%, and Papanicolaou smear (last year) 26% to 69%. The Aberdeen IHS area women with diabetes had 51% more clinic visits per year than women without diabetes, but the groups had similar screening rates. CONCLUSION: Cancer-screening rates for American Indian and Alaska Native women vary by region. In the Aberdeen IHS area, women with diabetes had more visits (missed opportunities) but similar screening rates as women without diabetes. The diabetic audit could be used to monitor national IHS cancer-screening trends for women with diabetes and in the Aberdeen IHS area for all women aged 50 to 69 years.

Prevalence and correlates of aortic regurgitation in American Indians: the Strong Heart Study.

OBJECTIVES: We sought to determine the prevalence and correlates of aortic regurgitation (AR) in a population-based sample group. BACKGROUND: Concern over induction of AR by weight loss medication highlights the importance of assessing the prevalence and correlates of AR in unselected patient groups. METHODS: Aortic regurgitation was assessed by color flow Doppler echocardiography in 3,501 American Indian participants age 47 to 81 years during the second Strong Heart Study. RESULTS: Mild (1+) AR was present in 7.3%, 2+ AR in 2.4% and 3+ to 4+ AR in 0.3% of participants, more frequently in those > or =60 years old than in those <60 years old (14.4% vs. 5.8%, p<0.001); AR was unrelated to gender. Compared with participants without AR, those with mild AR had a lower body mass index (p<0.004) and higher systolic pressure (p<0.003). Participants with AR had larger aortic root diameters (3.6+/-0.4 vs. 3.4+/-0.4 cm, p<0.001), higher creatinine levels (1.3+/-1.3 vs. 1.0+/-1.0 mg/dl, p<0.001) and higher urine albumin/creatinine levels (3.6+/-2.3 vs. 3.3+/-2.0 log, p<0.001), as well as higher prevalences of aortic stenosis (AS) or mitral stenosis (MS) (p<0.001). Regression analysis showed that AR was independently related to older age and larger aortic roots (p<0.0001), AS and absence of diabetes (p = 0.002), MS (p = 0.003) and higher log urine albumin/creatinine (p = 0.005). CONCLUSIONS: Aortic regurgitation occurred in 10% of a sample group of middle-aged to older adults and was related to older age, larger aortic root diameter, aortic and mitral stenosis and albuminuria. There was no association of AR with being overweight and a negative association of AR with diabetes.

Relation of generalized and central obesity to cardiovascular risk factors and prevalent coronary heart disease in a sample of American Indians: the Strong Heart Study.

OBJECTIVE: To examine the hypothesis linking measures of obesity including body mass index (BMI), waist circumference (waist) and percentage body fat to coronary heart disease (CHD) prevalence and its risk factors in American Indians. DESIGN: The Strong Heart Study assesses the prevalence of CHD and its risk factors in American Indians in Arizona, Oklahoma and South/North Dakota. Participants underwent a physical examination and an electrocardiogram; anthropometric and blood pressure measurements were taken, as were measurements of glucose, lipoproteins, fibrinogen, insulin, hemoglobin A1c and urinary albumin. PARTICIPANTS: Data were available for 4549 men and women between 45 and 74 y of age. MEASUREMENTS: Obesity, measured using body mass index, waist circumference and percentage body fat, was correlated with prevalent CHD and its risk factors. RESULTS: More than 75% of participants were overweight (BMI>25 kg/m2). Measures of obesity were greater in women than in men, in younger than in older participants, and in participants with diabetes than in nondiabetic participants. CHD risk factors were associated with measures of obesity but, except for insulin concentration, changes in metabolic variables with increasing obesity were small. Associations were not stronger with waist than with BMI. The prevalence of CHD in those whose BMI and/or waist measurements lay in the lowest and highest quintiles, by gender and diabetic status, was similar. CONCLUSIONS: Although CHD risk factors are associated with obesity in American Indians, distribution of obesity (ie waist) is no more closely related to risk factors than is generalized obesity (ie BMI), and changes in CHD risk factors with obesity were small. Thus, the relations among obesity, body fat distribution and CHD risk may differ in this population.

Prevalence of undiagnosed diabetes in three American Indian populations. A comparison of the 1997 American Diabetes Association diagnostic criteria and the 1985 World Health Organization diagnostic criteria: the Strong Heart Study.

OBJECTIVE: In 1997, the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus of the American Diabetes Association (ADA) recommended three new sets of criteria for the diagnosis of diabetes that were different from those established by the World Health Organization (WHO) in 1985. One of these three methods was based on a fasting plasma glucose value only. This article compares ADA criteria with WHO criteria by applying them to three subgroups of American Indians in the Strong Heart Study who had no known diabetes. RESEARCH DESIGN AND METHODS: The Strong Heart Study is a prospective epidemiological study of vascular disease in three American Indian populations aged 45-74 years. During the baseline examination from 1988 to 1991, participants without diagnosed diabetes underwent a fasting glucose test and a 2-h oral glucose tolerance test. These values were used to compare the ADA and WHO diagnostic criteria. RESULTS: By using fasting and 2-h glucose values, prevalence rates of undiagnosed diabetes were 15.9% according to WHO criteria and 14.4% according to ADA criteria. The overall agreement rate was 65%, and the weighted kappa statistic was 0.474, which indicates moderate agreement. The age-specific analysis showed that, among participants between 45 and 54 years of age, the prevalence rates of undiagnosed diabetes were 13.4% according to WHO criteria and 12.7% according to ADA criteria. Among those aged 55-74 years, the rates were 18.7% according to WHO criteria and 16.3% according to ADA criteria. Thus, the difference in the prevalence rates when using WHO and ADA criteria, although generally small in this population, was three times higher in the older group (2.4%) than the difference in the younger group (0.7%). CONCLUSIONS: The Strong Heart Study found that prevalence rates of undiagnosed diabetes determined by ADA criteria and WHO criteria were similar in its American Indian population. The data suggest that the difference between the two criteria may increase as age increases. Longitudinal data will be needed to evaluate further the utility of the two criteria.